Metal-terminal adhesive film and manufacturing method for same, metal-terminal equipped with metal-terminal adhesive film, power-storage-device exterior material, kit comprising power-storage-device exterior material and metal-terminal adhesive film, and power storage device and manufacturing method for same

Abstract

This metal-terminal adhesive film is interposed between a metal terminal electrically connected to an electrode of an electronic device element and a power-storage-device exterior material for sealing the power-storage-device element. The power-storage-device exterior material is provided with a heat-fusible resin layer disposed on the outermost surface on the power-storage-device element side. The metal-terminal adhesive film is provided with a resin layer A constituting a one-side surface. The metal-terminal adhesive film and all precious metal terminals are heat-fused at a temperature of 200° C, a pressure of 0.25 MPa, and for a duration of 16 seconds to obtain a metal terminal equipped with the metal-terminal adhesive film which has the resin layer A disposed on the surface thereof. The absolute value |P-Q| of the difference between the degree of orientation P, which is measured for the resin layer A of the metal terminal equipped with the metal-terminal adhesive film, and the degree of orientation Q of the heat-fusible resin layer, which is 0.000−0.100, is less than or equal to 0.200.

Description

Adhesive film for metal terminal and manufacturing method thereof, metal terminal with adhesive film for metal terminal, exterior material for electricity storage device, kit including exterior material for electricity storage device and adhesive film for metal terminal, and electricity storage device and manufacturing method thereof

[0001] The present disclosure relates to an adhesive film for metal terminals and a method for manufacturing the same, a metal terminal with an adhesive film for metal terminals, an exterior material for an electricity storage device, a kit including an exterior material for an electricity storage device and an adhesive film for metal terminals, and an electricity storage device and a method for manufacturing the same.

[0002] Various types of electricity storage devices have been developed to date, and in all electricity storage devices, exterior materials for electricity storage devices have become essential components for sealing electricity storage device elements such as electrodes and electrolytes. Metal exterior materials for electricity storage devices have traditionally been widely used as exterior materials for electricity storage devices. However, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and the like, electricity storage devices are being required to have a variety of shapes, as well as to be thinner and lighter. However, the metal exterior materials for electricity storage devices that have traditionally been widely used have the drawbacks of being difficult to keep up with the diversification of shapes and also having limitations on how much they can be made lighter.

[0003] Therefore, in recent years, a laminate sheet in which a base material layer / an adhesive layer / a barrier layer / a heat-sealable resin layer are laminated in this order has been proposed as an electrical storage device packaging material that can be easily processed into a variety of shapes and can achieve thinning and weight reduction. When such a laminate film-like electrical storage device packaging material is used, the electrical storage device elements are sealed by the electrical storage device packaging material by heat-sealing the peripheral edge of the electrical storage device packaging material with the heat-sealable resin layers positioned in the innermost layers of the electrical storage device packaging material facing each other.

[0004] Metal terminals protrude from the heat-sealed portions of the exterior material for an electricity storage device, and the electricity storage device elements sealed with the exterior material for an electricity storage device are electrically connected to the outside via the metal terminals electrically connected to the electrodes of the electricity storage device elements. That is, the portions of the heat-sealed exterior material for an electricity storage device where the metal terminals are present are heat-sealed in a state where the metal terminals are sandwiched between the heat-sealable resin layers. Because the metal terminals and the heat-sealable resin layer are made of different materials, adhesion is likely to decrease at the interface between the metal terminals and the heat-sealable resin layer.

[0005] For this reason, an adhesive film is sometimes disposed between the metal terminal and the heat-sealable resin layer in order to enhance adhesion therebetween, etc. Examples of such adhesive films include those described in Patent Document 1.

[0006] JP 2015-79638 A

[0007] As described above, the heat-sealable resin layer and the metal terminal of the packaging material for an electricity storage device are made of different materials, and therefore adhesion at the interface between the metal terminal and the heat-sealable resin layer is likely to decrease. For this reason, an adhesive film is sometimes disposed between the metal terminal and the heat-sealable resin layer for the purpose of improving adhesion therebetween.

[0008] Even when an adhesive film is used, if the adhesive strength when the adhesive film and the heat-sealable resin layer of the exterior material for an electricity storage device are heat-sealed can be increased, the sealing property of the electricity storage device can be further improved.

[0009] A primary object of the present disclosure is to provide an adhesive film for metal terminals that is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that encapsulates the electricity storage device element, the adhesive film being capable of exhibiting high adhesive strength when the adhesive film is heat-sealed to a heat-sealable resin layer of the exterior material for an electricity storage device. Further objects of the present disclosure include providing a method for manufacturing the adhesive film for metal terminals, a metal terminal with an adhesive film for metal terminals, an exterior material for an electricity storage device, a kit including an exterior material for an electricity storage device and the adhesive film for metal terminals, an electricity storage device, and a method for manufacturing the electricity storage device.

[0010] The inventors of the present disclosure have conducted extensive research to solve the above problems. As a result, the inventors discovered that in an adhesive film for metal terminals interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element, the exterior material for an electricity storage device comprises a heat-sealable resin layer that is disposed on the outermost surface on the electricity storage device element side, and the adhesive film for metal terminal comprises a resin layer A that constitutes the surface of one side, and the adhesive film for metal terminal and the metal terminal are heat-sealed under conditions of a temperature of 200°C, a pressure of 0.25 MPa, and a time period of 16 seconds to obtain a metal terminal with an adhesive film for metal terminal that is disposed so that the resin layer A is located on the surface, and that when the absolute value |P-Q| of the difference between the degree of orientation P measured for the resin layer A of the metal terminal with the adhesive film for metal terminal and the degree of orientation Q of a heat-sealable resin layer having an orientation degree of 0.000 to 0.100 is a predetermined value or less, high adhesive strength can be exhibited when the adhesive film and the heat-sealable resin layer of the exterior material for an electricity storage device are heat-sealed.

[0011] That is, the present disclosure provides the following aspects of the invention: An adhesive film for metal terminal interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element, wherein the exterior material for an electricity storage device comprises a heat-sealable resin layer disposed on the outermost surface facing the electricity storage device element, and the adhesive film for metal terminal comprises a resin layer A that constitutes one of the surfaces, and the adhesive film for metal terminal and the metal terminal are heat-sealed together under conditions of a temperature of 200°C, a pressure of 0.25 MPa, and a time period of 16 seconds to obtain a metal terminal with an adhesive film for metal terminal disposed so that the resin layer A is located on the surface, and the absolute value |P−Q| of the difference between the degree of orientation P measured for the resin layer A of the metal terminal with the adhesive film for metal terminal and the degree of orientation Q of the heat-sealable resin layer having an orientation degree of 0.000 to 0.100 is 0.200 or less.

[0012] According to the present disclosure, it is possible to provide an adhesive film for metal terminals that is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that encapsulates the electricity storage device element, and that can exhibit high adhesive strength when the adhesive film and the heat-sealable resin layer of the exterior material for an electricity storage device are heat-sealed.Furthermore, it is an object of the present disclosure to provide a method for manufacturing the adhesive film for metal terminals, a metal terminal with an adhesive film for metal terminals, an exterior material for an electricity storage device, a kit including an exterior material for an electricity storage device and an adhesive film for metal terminals, and an electricity storage device and a method for manufacturing the same.

[0013] FIG. 1 is a schematic plan view of an electricity storage device according to the present disclosure. FIG. 2 is a schematic cross-sectional view taken along line A-A' in FIG. 1. FIG. 3 is a schematic cross-sectional view taken along line B-B' in FIG. 1. FIG. 4 is a schematic cross-sectional view of an adhesive film for a metal terminal according to the present disclosure. FIG. 5 is a schematic cross-sectional view of an adhesive film for a metal terminal according to the present disclosure. FIG. 6 is a schematic cross-sectional view of an adhesive film for a metal terminal according to the present disclosure. FIG. 7 is a schematic cross-sectional view of an outer casing material for an electricity storage device according to the present disclosure. FIG. 8 is a schematic view illustrating a method for measuring the adhesive strength between an adhesive film and an outer casing material. FIG. 9 is a schematic view illustrating a method for measuring the adhesive strength between an adhesive film and an outer casing material.

[0014] The adhesive film for metal terminals of the present disclosure is an adhesive film for metal terminals interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that encapsulates the electricity storage device element. The exterior material for an electricity storage device includes a heat-sealable resin layer disposed on the outermost surface facing the electricity storage device element. The adhesive film for metal terminals includes a resin layer A constituting one surface, and the adhesive film for metal terminals and the metal terminal are heat-sealed together at a temperature of 200°C and a pressure of 0.25 MPa for 16 seconds to obtain a metal terminal with the adhesive film for metal terminals disposed so that the resin layer A is positioned on the surface. The absolute value |P−Q| of the difference between the degree of orientation P measured for the resin layer A of the metal terminal with the adhesive film for metal terminals and the degree of orientation Q of the heat-sealable resin layer, which has an orientation degree of 0.000 to 0.100, is 0.200 or less.

[0015] Because the adhesive film for metal terminals of the present disclosure has these characteristics, it can exhibit high adhesive strength when the adhesive film and the heat-sealable resin layer of the exterior material for an electricity storage device are heat-sealed.

[0016] The electricity storage device of the present disclosure is also an electricity storage device comprising at least an electricity storage device element having a positive electrode, a negative electrode, and an electrolyte, an exterior material for an electricity storage device that seals the electricity storage device element, and metal terminals that are electrically connected to the positive electrode and the negative electrode, respectively, and protrude outside the exterior material for an electricity storage device, and is characterized in that an adhesive film for metal terminals of the present disclosure is interposed between the metal terminals and the exterior material for an electricity storage device.

[0017] The adhesive film for metal terminal and its manufacturing method, and the electricity storage device and its manufacturing method according to the present disclosure will be described in detail below.

[0018] In this specification, when referring to a numerical range, a numerical range indicated with "to" means "greater than or equal to" or "less than or equal to." For example, the notation 2 to 15 mm means 2 mm or greater and 15 mm or less. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, separately described upper and lower limits, upper and lower limits, or lower and lower limits may each be combined to form a numerical range. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0019] Another method for confirming the MD of an adhesive film for metal terminals is to observe a cross section of the adhesive film for metal terminals (e.g., a cross section of an acid-modified polyolefin layer or a polyolefin layer) using an electron microscope to confirm the sea-island structure. In this method, the direction parallel to the cross section in which the average diameter of the island shapes in the direction perpendicular to the thickness direction of the adhesive film for metal terminals is largest can be determined as the MD. Specifically, the sea-island structure is confirmed by observing, using an electron microscope, a cross section of the adhesive film for metal terminals in the longitudinal direction and each cross section at an angle of 10 degrees from the direction parallel to the longitudinal cross section to the direction perpendicular to the longitudinal cross section (a total of 10 cross sections). Next, the shape of each individual island is observed in each cross section. For each island shape, the linear distance connecting the leftmost end perpendicular to the thickness direction of the adhesive film for metal terminals to the rightmost end in the vertical direction is defined as the diameter y. For each cross section, the average of the diameters y of the top 20 island shapes in order of largest diameter y is calculated. The direction parallel to the cross section in which the average diameter y of the island shape is the largest is determined to be the MD. Alternatively, for example, the adhesive film for metal terminals can be left in an environment of 150°C for 2 minutes, and the thermal shrinkage rate measured, and the direction with the larger shrinkage rate determined to be the MD.

[0020] 1. Adhesive Film for Metal Terminal The adhesive film for metal terminal of the present disclosure is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that encapsulates the electricity storage device element. Specifically, as shown in Figures 1 to 3, for example, an adhesive film for metal terminal 1 of the present disclosure is interposed between a metal terminal 2 electrically connected to an electrode of an electricity storage device element 4 and an exterior material for an electricity storage device 3 that encapsulates the electricity storage device element 4. The metal terminal 2 protrudes outside the exterior material for an electricity storage device 3 and is sandwiched between the exterior material for an electricity storage device 3, via the adhesive film for metal terminal 1, at a peripheral portion 3a of the heat-sealed exterior material for an electricity storage device 3.

[0021] In the present disclosure, the temporary bonding step of the adhesive film for metal terminal to the metal terminal is carried out, for example, under conditions of a temperature of about 140 to 160°C, a pressure of about 0.01 to 1.0 MPa, a time of about 3 to 15 seconds, and a number of times of about 3 to 6, while the main bonding step is carried out, for example, under conditions of a temperature of about 160 to 240°C, a pressure of about 0.01 to 1.0 MPa, a time of about 3 to 15 seconds, and a number of times of about 1 to 3. Furthermore, when heat-sealing the metal terminal with the adhesive film for metal terminal interposed between the exterior material for an electricity storage device, the heating temperature is typically in the range of about 180 to 210°C, the pressure is typically about 1.0 to 5.0 MPa, the time is about 1 to 5 seconds, and a number of times of about 1.

[0022] The adhesive film 1 for metal terminals of the present disclosure is provided to improve adhesion between the metal terminal 2 and the electricity storage device exterior material 3. By improving adhesion between the metal terminal 2 and the electricity storage device exterior material 3, the sealing performance of the electricity storage device element 4 is improved. As described above, when the electricity storage device element 4 is heat-sealed, the electricity storage device element is sealed such that the metal terminal 2 electrically connected to the electrode of the electricity storage device element 4 protrudes outside the electricity storage device exterior material 3. At this time, the metal terminal 2 made of metal and the heat-sealable resin layer 35 (a layer made of a heat-sealable resin such as polyolefin) located in the innermost layer of the electricity storage device exterior material 3 are made of different materials. Therefore, without using such an adhesive film, the sealing performance of the electricity storage device element is likely to be reduced at the interface between the metal terminal 2 and the heat-sealable resin layer 35.

[0023] [Resin Layer A] The adhesive film 1 for metal terminal of the present disclosure includes at least a resin layer A. The resin layer A forms at least one surface of the adhesive film 1 for metal terminal and is the outermost layer. That is, the adhesive film 1 for metal terminal of the present disclosure includes at least one resin layer A, and at least one surface of the adhesive film 1 for metal terminal is formed by the resin layer A. As long as the effects of the present disclosure are achieved, the adhesive film 1 for metal terminal of the present disclosure may be a single layer as shown in FIG. 4 or may have a multilayer structure (multilayer) as shown in FIGS. 5 to 7.

[0024] When the adhesive film for metal terminal 1 of the present disclosure is a single layer, the adhesive film for metal terminal 1 is constituted by a resin layer A, and the surface on the metal terminal side and the surface of the exterior material for an electrical storage device are formed by this resin layer A. In this case, the resin forming the surface on the exterior material for an electrical storage device side of the adhesive film for metal terminal 1 and the resin forming the surface on the metal terminal side are the same resin (i.e., the resin constituting resin layer A). Note that the resin forming the surface on the exterior material for an electrical storage device side of the adhesive film for metal terminal 1 and the resin forming the surface on the metal terminal side being common means that, for example, 80% by mass or more of the components in these resins are the same, more preferably 90% by mass or more are the same, even more preferably 95% by mass or more are the same, and even more preferably 100% by mass are the same.

[0025] When the adhesive film for metal terminal 1 of the present disclosure has a multilayer structure (multilayer), at least one layer needs to be composed of resin layer A. For example, as shown in FIG. 5, when the adhesive film for metal terminal 1 of the present disclosure has a two-layer structure, the adhesive film for metal terminal 1 is a laminate of a first resin layer 12a and a second resin layer 12b. As described below, in the present disclosure, of these layers, the second resin layer 12b is composed of resin layer A. Furthermore, by forming the surface of the outer layer material for an electrical storage device, in the state of the metal terminal with the adhesive film for metal terminal, the second resin layer 12b (resin layer A) faces the heat-sealable resin layer of the outer layer material for an electrical storage device and becomes heat-sealable. Even when the adhesive film for metal terminal 1 of the present disclosure has a multilayer structure (multilayer), the resin forming the surface of the outer layer material for an electrical storage device and the resin forming the surface of the metal terminal may be the same resin.

[0026] 6, when the adhesive film for metal terminal 1 of the present disclosure has a three-layer structure, the adhesive film for metal terminal 1 is a laminate in which a first resin layer 12a, an intermediate layer 11, and a second resin layer 12b are laminated in this order. In the present disclosure, the first resin layer 12a forms the surface on the metal terminal side, and the second resin layer 12b forms the surface on the exterior material side for an electricity storage device.

[0027] The surface of the adhesive film for metal terminal 1 of the present disclosure facing the exterior packaging material for an electricity storage device (i.e., the surface of the second resin layer 12b (resin layer A)) has thermal adhesion to a thermally adhesive resin layer described below. In the present disclosure, of the first resin layer 12a and the second resin layer 12b, at least the second resin layer 12b is formed by the resin layer A.

[0028] The first resin layer 12a constituting the surface on the metal terminal side of the adhesive film for metal terminal 1 of the present disclosure has thermal adhesion to metal (the metal constituting the metal terminal). Therefore, when using the adhesive film for metal terminal 1 of the present disclosure, it is preferable to place the first resin layer 12a on the metal terminal side.

[0029] The resin layer A is preferably a layer containing a polyolefin skeleton such as polyolefin, and more preferably a layer containing polyolefin. From the viewpoint of more suitably exhibiting the effects of the present disclosure, the resin layer A is preferably formed from polyolefin. That is, the resin layer A can be suitably constituted by a polyolefin film.

[0030] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred, and polypropylene is particularly preferred.

[0031] The polyolefin may be a cyclic polyolefin. Cyclic polyolefins are copolymers of olefins and cyclic monomers, and examples of olefins constituting the cyclic polyolefins include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of cyclic monomers constituting the cyclic polyolefins include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkenes are preferred, and norbornene is more preferred. Styrene is also an example of a constituting monomer.

[0032] 4, the adhesive film 1 for a metal terminal must have thermal adhesion to the surface of the metal terminal and the surface of the exterior material for an electrical storage device, and in particular, taking into consideration thermal adhesion to metal, the polyolefin may be an acid-modified polyolefin (i.e., an acid-modified polyolefin). The acid-modified polyolefin is not particularly limited as long as it is an acid-modified polyolefin, but preferably includes a polyolefin graft-modified with an unsaturated carboxylic acid or an anhydride thereof.

[0033] Specific examples of polyolefins to be acid-modified include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred, and polypropylene is particularly preferred.

[0034] The acid-modified polyolefin may be a cyclic polyolefin. For example, a carboxylic acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a cyclic polyolefin by substituting an α,β-unsaturated carboxylic acid or an anhydride thereof for some of the monomers constituting the cyclic polyolefin, or by block polymerizing or graft polymerizing an α,β-unsaturated carboxylic acid or an anhydride thereof with a cyclic polyolefin.

[0035] The acid-modified cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomer constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, preferred are cyclic alkenes, and more preferred are norbornene. Another example of the constituting monomer is styrene.

[0036] Examples of carboxylic acids or anhydrides thereof used for acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride, etc. When the resin layer A is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is preferably detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wave number of 1760 cm. -1 Nearby and wave number 1780 cm -1 A peak derived from maleic anhydride is detected around . When resin layer A is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected when measured by infrared spectroscopy. However, if the degree of acid modification is low, the peak becomes small and may not be detected. In such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

[0037] Furthermore, when the adhesive film 1 for metal terminals has a multilayer structure (multilayer) as shown in Figures 5 to 7, it is sufficient that the surface on the metal terminal side is provided with a resin layer that has heat-sealing properties with the metal, while the surface of the electrical storage device exterior material is provided with a resin layer A that has heat-sealing properties only with the heat-sealing resin layer of the electrical storage device exterior material. Therefore, considering that the resin used in the heat-sealing resin layer of the electrical storage device exterior material is an acid-unmodified polyolefin, particularly an acid-unmodified polypropylene, and that resins of the same type have excellent heat-sealing properties, the resin layer A can be suitably constituted by an acid-unmodified polyolefin film, and in particular, can be suitably constituted by an acid-unmodified polypropylene film.

[0038] In the present disclosure, an adhesive film and a metal terminal are heat-sealed under conditions of a temperature of 200°C, a pressure of 0.25 MPa, and a time of 16 seconds to obtain a metal terminal with an adhesive film in which resin layer A is positioned on the surface, and the absolute value |P-Q| of the difference between the orientation degree P measured for resin layer A of the metal terminal with adhesive film and the orientation degree Q of the heat-sealable resin layer having an orientation degree of 0.000 to 0.100 is 0.200 or less.

[0039] From the viewpoint of more suitably exerting the effects of the present disclosure, the absolute value of the difference between the degrees of orientation P and Q, |P-Q|, is preferably 0.190 or less, more preferably 0.180 or less, and even more preferably 0.110 or less. The lower limit of the difference may be, for example, 0.000 or 0.001. Preferred ranges include 0.000 to 0.190, 0.000 to 0.180, 0.000 to 0.110, 0.001 to 0.190, 0.001 to 0.180, and 0.001 to 0.110.

[0040] The degree of orientation P of the resin layer A of the adhesive film is preferably 0.300 or less, more preferably 0.250 or less, and even more preferably 0.245 or less. The lower limit may be, for example, 0.000 or 0.001. Preferred ranges include 0.000 to 0.300, 0.000 to 0.250, 0.000 to 0.245, 0.001 to 0.300, 0.001 to 0.250, and 0.001 to 0.245.

[0041] The orientation degree Q of the heat-fusible resin layer of the exterior packaging material for an electricity storage device is preferably 0.100 or less, more preferably 0.090 or less, even more preferably 0.060 or less, and even more preferably 0.050 or less. The lower limit is, for example, 0.000 or 0.001. Preferred ranges include about 0.000 to 0.100, about 0.000 to 0.090, about 0.000 to 0.060, about 0.000 to 0.050, about 0.001 to 0.100, about 0.001 to 0.090, about 0.001 to 0.060, and about 0.001 to 0.050.

[0042] <Measurement of the orientation degree P of the resin layer A of the adhesive film and the orientation degree Q of the heat-sealable resin layer of the packaging material> The other surface of an adhesive film (MD 40 mm, TD 10 mm) having a resin layer A constituting one surface was heat-sealed to a metal terminal (length 22.5 mm, width 30 mm, thickness 0.4 mm) at a temperature of 200°C, a pressure of 0.25 MPa, and for 16 seconds (one time) to obtain a metal terminal with an adhesive film arranged so that the resin layer A was located on the surface, and this was used as a measurement sample. At this time, the MD of the adhesive film and the longitudinal direction of the metal terminal were aligned. Furthermore, in the state of a metal terminal with an adhesive film for a metal terminal, the resin layer A was located on the outermost surface. Pole measurements were performed on the resin layer A of the metal terminal with an adhesive film and the heat-sealable resin layer of the packaging material for an electricity storage device, respectively, under the following measurement conditions. Next, from the obtained diffraction intensity spectrum, the degree of orientation P of the resin layer A of the metal terminal with adhesive film and the degree of orientation Q of the heat-sealable resin layer of the exterior material for a storage battery device (each heat-sealable resin layer has an orientation Q in the range of 0.000 to 0.100) are measured under the following analysis conditions.

[0043] (Measurement Conditions) After performing pole measurement under the following measurement conditions, the degrees of orientation P and Q of the resin layer A and the heat-fusible resin layer, and the absolute value of their difference |P−Q| are determined from the obtained diffraction intensity spectrum under the following analysis conditions.

[0044] X-rays: CuKα rays (1.548 Å) Tube voltage: 45 kV Tube current: 200 mA Optical system: Inplane pole measurement Entrance slit: 5 mm 2θ angle: 16.8° (PP 040 plane) Detector: Scintillation counter Sample form: The film was cut into a circle with a diameter of 2 cm and placed with the fused surface facing upwards. In the sample of the exterior material for an electricity storage device, the fused surface is the surface made up of the heat-sealable resin layer, and in the sample of the metal terminal with adhesive film, it is the surface made up of resin layer A.

[0045] <Analysis Conditions> After integrating the spectral intensity for an α angle of 0° to 30° (the horizontal direction of the sample is taken as 0°), the average spectral intensity for a β angle of 70° to 110° and 250° to 290° (the MD direction of the sample is taken as 0°) and the average spectral intensity for a β angle of 0° to 20°, 160° to 200°, and 340° to 360° are calculated, and these are designated as S1 and S2, respectively. From the obtained average spectral intensities S1 and S2, a quantity defined as |(S1-S2) / (S1+S2)| is calculated, and this is taken as the degree of orientation. The degree of orientation of resin layer A is designated as P, the degree of orientation of the heat-fusible resin layer is designated as Q, and the absolute value of the difference between the two, |P-Q|, is calculated.

[0046] Methods for adjusting the degree of orientation P of the resin layer A of the adhesive film include, for example, the molding method used to form the resin layer A (e.g., the type of molding method, such as extrusion or inflation, the cooling temperature, cooling time, line speed, and clearance), the resin blend, and the selection of resin type. For example, slowing the extrusion speed during film formation tends to increase the degree of orientation P, while increasing the extrusion speed during film formation tends to decrease the degree of orientation P. In addition, in the molding of the resin layer A, the film formation temperature, film formation speed, and cooling conditions (chill roll temperature) are conditions that have a significant impact on adjusting the degree of orientation P of the resin layer A. For example, when the film formation temperature and film formation speed are high and the chill roll temperature is low, the extruded resin is rapidly cooled. This reduces the degree of orientation P. On the other hand, when the film formation temperature and film formation speed are low and the chill roll temperature is high, the extruded resin is slowly cooled, and the degree of orientation P increases. The thickness of the resin layer A also affects the degree of orientation P. An exterior packaging material for an electricity storage device is prepared, which includes a heat-fusible resin layer having an orientation degree Q of 0.000 to 0.100, and a measurement sample is prepared as described above to measure the orientation degree P. From these measurement results, a resin film for forming the resin layer A is selected (for example, it may be selected from commercially available products), and a resin film for which the difference |P−Q| between the orientation degrees P and Q is 0.200 or less is used as the resin layer A of the present disclosure.

[0047] In the adhesive film 1 for metal terminals of the present disclosure, the difference |P-Q| between the degrees of orientation P and Q is 0.200 or less, so that high adhesive strength can be exhibited when the adhesive film and the heat-sealable resin layer of the electrical storage device packaging material are heat-sealed. The reason for this can be considered as follows. That is, because the difference (absolute value) between the degree of orientation P of the resin layer A of the adhesive film after heat-sealing to the metal terminal and the degree of orientation Q of the heat-sealable resin layer of the electrical storage device packaging material is a very small value of 0.200 or less, the crystal orientation directions of these resins are aligned at the interface between the resin layer A and the heat-sealable resin layer, making these layers more easily intermixed and facilitating integration. As a result, it can be considered that these layers are firmly bonded together, resulting in high adhesive strength.

[0048] Furthermore, the degree of orientation of the resin layer A of the adhesive film before the adhesive film is heat-sealed to the metal terminal is preferably 0.300 or less, more preferably 0.200 or less, and even more preferably 0.100 or less. The lower limit is, for example, 0.000 or 0.001. Preferred ranges include 0.000 to 0.300, 0.000 to 0.200, 0.000 to 0.100, 0.001 to 0.300, 0.001 to 0.200, and 0.001 to 0.100.

[0049] <Orientation degree of resin layer A of adhesive film before heat fusion> The orientation degree of resin layer A of adhesive film before heat fusion is measured in the same manner as the orientation degree P of resin layer A of adhesive film described above, except that the measurement object is the surface of resin layer A of adhesive film before heat fusion.

[0050] The adhesive film of the present disclosure has a temperature at 90% by volume melting (the melting temperature (°C) when the adhesive film of the present disclosure is heated by the method described below and the melting rate is 90% by volume) of preferably 105°C or higher, more preferably 108°C or higher, and even more preferably 110°C or higher, and preferably 125°C or lower, more preferably 122°C or lower, and even more preferably 120°C or lower. Preferred ranges are about 105 to 125°C, about 105 to 122°C, about 105 to 120°C, about 108 to 125°C, about 108 to 122°C, about 108 to 120°C, about 110 to 125°C, about 110 to 122°C, or about 110 to 120°C. Furthermore, the temperature of resin layer A at 75% by volume melting is preferably 100°C or higher, more preferably 105°C or higher, even more preferably 107°C or higher, and is preferably 125°C or lower, more preferably 120°C or lower, even more preferably 118°C or lower, with preferred ranges being about 100 to 125°C, about 100 to 120°C, about 100 to 118°C, about 105 to 125°C, about 105 to 120°C, about 105 to 118°C, about 107 to 125°C, about 107 to 120°C, or about 107 to 118°C. Furthermore, the temperature of resin layer A at 50% by volume melting is preferably 90°C or higher, more preferably 95°C or higher, and even more preferably 98°C or higher, and is preferably 120°C or lower, more preferably 116°C or lower, and even more preferably 114°C or lower, with preferred ranges being approximately 90 to 120°C, approximately 90 to 116°C, approximately 90 to 114°C, approximately 95 to 120°C, approximately 95 to 116°C, approximately 95 to 114°C, approximately 98 to 120°C, approximately 98 to 116°C, and approximately 98 to 114°C. Furthermore, the temperature of resin layer A at 25% by volume melting is preferably 90°C or higher, more preferably 92°C or higher, even more preferably 94°C or higher, and even more preferably 100°C or higher, and is preferably 115°C or lower, more preferably 110°C or lower, and even more preferably 102°C or lower. Preferred ranges are about 90 to 115°C, about 90 to 110°C, about 90 to 102°C, about 92 to 115°C, about 92 to 110°C, about 92 to 102°C, about 94 to 115°C, about 94 to 110°C, about 94 to 102°C, about 100 to 115°C, about 100 to 110°C, and about 100 to 102°C.Furthermore, the temperature of the resin layer A at 10% by volume melting is preferably 80 ° C. or higher, more preferably 85 ° C. or higher, and even more preferably 87 ° C. or higher, and preferably 110 ° C. or lower, more preferably 105 ° C. or lower, even more preferably 103 ° C. or lower, and even more preferably 93 ° C. or lower, and preferred ranges are about 80 to 110 ° C., about 80 to 105 ° C., about 80 to 103 ° C., about 80 to 93 ° C., about 85 to 110 ° C., about 85 to 105 ° C., about 85 to 103 ° C., about 85 to 93 ° C., about 87 to 110 ° C., about 87 to 105 ° C., about 87 to 103 ° C., about 87 to 93 ° C. For example, if the temperature at 25% by volume melting is 90 to 100 ° C., it is advantageous when heat-sealing the heat-sealable resin layer of the packaging material and the adhesive film in a low-temperature environment.

[0051] <Melting ratio (volume %) and melting temperature (°C) of adhesive film> According to the following procedure, an adhesive film is heated to 210°C to melt it, and then cooled from 210°C at a temperature decrease rate of 10°C / min, and the temperatures when the adhesive film is 90% by volume melted, 75% by volume melted, 50% by volume melted, 25% by volume melted, and 10% by volume melted are measured.

[0052] The heat of fusion of each measurement sample is measured in accordance with the provisions of JIS K 7122:2012. Measurements are performed using a differential scanning calorimeter. The measurement sample is held at -50°C for 15 minutes, then heated from -50°C to 210°C at a heating rate of 10°C / min, and the first heat of fusion ΔH (J / g) is measured, and then held at 210°C for 10 minutes. Next, the temperature is lowered from 210°C to -50°C at a heating rate of 10°C / min and held for 15 minutes. Furthermore, the temperature is raised from -50°C to 210°C at a heating rate of 10°C / min, and the second heat of fusion ΔH (J / g) is measured. The flow rate of nitrogen gas is 50 ml / min. The value of the heat of fusion ΔH (J / g) measured the first time using the above procedure is adopted. The heat of fusion is the melting peak area surrounded by the peak and the baseline (the straight line connecting the 80°C point on the DSC curve to the 170°C point). On the other hand, the crystalline heat of fusion in a temperature range below X°C is calculated from the area of ​​the temperature range below X°C in the melting peak area when calculating the total crystalline heat of fusion. In other words, the "melting fraction at temperature X°C" is a value calculated from the following formula: Melting fraction at temperature X°C (%) = {(area of ​​the melting peak area in the temperature range below temperature X) / (melting peak area)} × 100 ... formula Therefore, the temperature at 25% melting is the temperature X°C at which the melting fraction at temperature X (melting fraction (volume %)) = 25.

[0053] The resin layer A may be formed of one type of resin component alone, or may be formed of a blend polymer combining two or more types of resin components. From the viewpoint of film formability, the resin layer A is preferably formed of a blend polymer combining two or more types of resin components. When using a blend polymer, the resin layer A preferably contains, for example, polypropylene as the main component (50% by mass or more of a component) and 50% by mass or less of another resin (preferably polyethylene from the viewpoint of improving flexibility). On the other hand, from the viewpoint of the electrolyte resistance of the resin layer A, it is preferable that the resin layer A contains polypropylene alone as a resin.

[0054] The resin layer A may contain known additives as needed, as long as the effects of the present disclosure are not impaired.

[0055] For example, the resin layer A may contain a filler as needed. When the resin layer A contains a filler, the filler functions as a spacer, making it possible to effectively suppress short circuits between the metal terminal 2 and the barrier layer 33 of the electrical storage device packaging material 3. The particle size of the filler can be in the range of about 0.1 to 35 μm, preferably about 5.0 to 30 μm, and more preferably about 10 to 25 μm. The content of the filler can be in the range of about 5 to 30 parts by mass, more preferably about 10 to 20 parts by mass, relative to 100 parts by mass of the resin component forming the resin layer A.

[0056] The filler can be either inorganic or organic. Examples of inorganic fillers include carbon (carbon, graphite), silica, aluminum oxide, barium titanate, iron oxide, silicon carbide, zirconium oxide, zirconium silicate, magnesium oxide, titanium oxide, calcium aluminate, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, and calcium carbonate. Examples of organic fillers include fluororesins, phenolic resins, urea resins, epoxy resins, acrylic resins, benzoguanamine-formaldehyde condensates, melamine-formaldehyde condensates, cross-linked polymethyl methacrylates, and cross-linked polyethylenes. From the viewpoints of shape stability, rigidity, and content resistance, aluminum oxide, silica, fluororesins, acrylic resins, and benzoguanamine-formaldehyde condensates are preferred, with spherical aluminum oxide and silica being particularly preferred. As a method for mixing the filler into the resin component that forms the resin layer A, a method in which the two are melt-blended in advance using a Banbury mixer or the like to form a masterbatch and then mixed in a predetermined mixing ratio, or a method in which the filler is directly mixed with the resin component can be used.

[0057] Furthermore, the resin layer A may contain a pigment as needed. Various inorganic pigments can be used as the pigment. A specific example of the pigment is preferably carbon (carbon, graphite), which is exemplified as the filler above. Carbon (carbon, graphite) is a material generally used inside an electricity storage device and is not likely to leach into the electrolyte solution. Furthermore, the coloring effect is significant, and a sufficient coloring effect can be obtained with an amount added that does not impair adhesion. Furthermore, the coloring effect does not melt due to heat, and the apparent melt viscosity of the added resin can be increased. Furthermore, the pressed portion can be prevented from becoming thin during thermal bonding (heat sealing), thereby providing excellent sealing between the electricity storage device exterior material and the metal terminal.

[0058] When a pigment is added to the resin layer A, for example, when carbon black with a particle size of approximately 0.03 μm is used, the amount of pigment added is approximately 0.05 to 0.3 parts by mass, preferably approximately 0.1 to 0.2 parts by mass, per 100 parts by mass of the resin components forming the resin layer A. By adding a pigment to the resin layer A, the presence or absence of the adhesive film 1 for metal terminals can be detected by a sensor or visually inspected. When a filler and a pigment are added to the resin layer A, the filler and the pigment may be added to the same resin layer A. However, from the viewpoint of not impairing the thermal fusion properties of the adhesive film 1 for metal terminals, it is preferable to add the filler and the pigment separately to different layers (e.g., the first resin layer 12a, the second resin layer 12b, the intermediate layer 11, etc., described below).

[0059] From the viewpoint of more suitably achieving the effects of the present disclosure, the melting peak temperature of the resin layer A is preferably 125° C. or higher, more preferably about 130° C. or higher, and even more preferably about 135° C. or higher. From the same viewpoint, the melting peak temperature is, for example, 180° C. or lower, preferably 175° C. or lower, more preferably 170° C. or lower, even more preferably about 165° C. or lower, and even more preferably about 160° C. or lower. Preferred ranges of the melting peak temperature include about 125 to 180°C, about 125 to 175°C, about 125 to 170°C, about 125 to 165°C, about 125 to 160°C, about 130 to 180°C, about 130 to 175°C, about 130 to 170°C, about 130 to 165°C, about 130 to 160°C, about 135 to 180°C, about 135 to 175°C, about 135 to 170°C, about 135 to 165°C, and about 135 to 160°C. In the present disclosure, the method for measuring the melting peak temperature is as follows.

[0060] <Measurement of Melting Peak Temperature> The melting peak temperature of each measurement sample is measured in accordance with the provisions of JIS K7121:2012 (Method for measuring transition temperatures of plastics (JIS K7121:1987 Supplement 1)). The measurement is carried out using a differential scanning calorimeter (DSC). The measurement sample is held at -50°C for 15 minutes, then heated from -50°C to 210°C at a heating rate of 10°C / min, and the first melting peak temperature P (°C) is measured, and then held at 210°C for 10 minutes. Next, the temperature is lowered from 210°C to -50°C at a heating rate of 10°C / min and held for 15 minutes. Furthermore, the temperature is raised from -50°C to 210°C at a heating rate of 10°C / min, and the second melting peak temperature Q (°C) is measured. The flow rate of nitrogen gas is 50 ml / min. By the above procedure, the melting peak temperature P (°C) measured the first time and the melting peak temperature Q (°C) measured the second time are determined. The value of the melting peak temperature P (°C) measured the first time by the above procedure is adopted.

[0061] When the adhesive film 1 for a metal terminal of the present disclosure is constituted by a single layer of resin layer A, the total thickness of the adhesive film 1 for a metal terminal, which will be described later, corresponds to the thickness of resin layer A.

[0062] Furthermore, when the adhesive film 1 for metal terminals of the present disclosure is constructed with a multilayer structure (multiple layers), from the viewpoint of more suitably achieving the effects of the present disclosure, the thickness of the resin layer A is preferably about 10 μm or more, more preferably about 15 μm or more, even more preferably about 20 μm or more, even more preferably about 30 μm or more, even more preferably about 40 μm or more, even more preferably about 50 μm or more, and is preferably about 120 μm or less, more preferably about 100 μm or less, even more preferably 80 μm or less. Preferred ranges of the thickness of the resin layer A include about 10 to 120 μm, about 10 to 100 μm, about 10 to 80 μm, about 15 to 120 μm, about 15 to 100 μm, about 15 to 80 μm, about 20 to 120 μm, about 20 to 100 μm, about 20 to 80 μm, about 30 to 120 μm, about 30 to 100 μm, about 30 to 80 μm, about 40 to 120 μm, about 40 to 100 μm, about 40 to 80 μm, about 50 to 120 μm, about 50 to 100 μm, and about 50 to 80 μm. From the viewpoint of improving the insulating properties of the adhesive film for metal terminals, the thickness of the resin layer A is preferably about 55 μm or more, more preferably about 60 μm or more, and is preferably about 100 μm or less, more preferably about 90 μm or less, with preferred ranges including about 55 to 100 μm, about 55 to 90 μm, about 60 to 100 μm, and about 60 to 90 μm. Note that when the adhesive film for metal terminals 1 of the present disclosure contains multiple resin layers A, it is preferable that the thickness of each resin layer A be within the above-mentioned range.

[0063] As described above, the adhesive film for metal terminal 1 of the present disclosure can have a configuration in which at least a first resin layer 12a, an intermediate layer 11, and a second resin layer 12b are laminated in this order, as shown in Fig. 6, for example. In this configuration, the first resin layer 12a is disposed on the metal terminal 2 side. In this configuration, the first resin layer 12a and the second resin layer 12b are located on the surfaces of both sides, respectively. Furthermore, since the second resin layer 12b constitutes the surface on the electricity storage device exterior material 3 side, at least the second resin layer 12b is referred to as resin layer A.

[0064] The first resin layer 12a is a layer made of resin. The first resin layer 12a may be formed of a resin layer A, or may be formed of a resin layer B different from the resin layer A. Since the first resin layer 12a is disposed on the metal terminal 2 side, it preferably contains the acid-modified polyolefin described above, and is preferably formed of the acid-modified polyolefin. That is, the first resin layer 12a can be suitably formed of an acid-modified polyolefin film. The acid-modified polyolefin is as described for the resin layer A.

[0065] The intermediate layer 11 may also be formed from the resin layer A, or may be formed from a resin layer B different from the resin layer A.

[0066] [Resin Layer B] Examples of resins constituting the resin layer B include polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicone resins, phenolic resins, polyetherimides, polyimides, polycarbonates, and mixtures or copolymers thereof, among which polyolefin resins are particularly preferred. Examples of polyolefin resins include polyolefins and acid-modified polyolefins.

[0067] As described below, the first resin layer 12a preferably contains a polyolefin-based resin (i.e., has a polyolefin skeleton), preferably contains a polyolefin, and more preferably is a layer formed of a polyolefin. Among polyolefin-based resins, the first resin layer 12a preferably contains a polyolefin or an acid-modified polyolefin, more preferably contains an acid-modified polyolefin, and more preferably is a layer formed of an acid-modified polyolefin.

[0068] The intermediate layer 11 preferably contains a polyolefin resin (i.e., has a polyolefin skeleton), preferably contains a polyolefin, and more preferably is a layer formed of a polyolefin.

[0069] In the resin layer B used in the first resin layer 12a and the intermediate layer 11, the polyolefin resin is preferably a polypropylene resin. The polyolefin is preferably polypropylene, and the acid-modified polyolefin is preferably acid-modified polypropylene.

[0070] The resin layer B may be formed of one type of resin component alone, or may be formed of a blend polymer combining two or more resin components. From the viewpoint of film formability, the resin layer B is preferably formed of a blend polymer combining two or more resin components. When using a blend polymer, the resin layer B preferably contains acid-modified polypropylene as the main component (50% by mass or more of a component) and 50% by mass or less of another resin (preferably polyethylene from the viewpoint of improving flexibility). Furthermore, the resin layer B containing acid-modified polypropylene preferably contains acid-modified polypropylene as the main component (50% by mass or more of a component) and 50% by mass or less of another resin (preferably polyethylene from the viewpoint of improving flexibility). On the other hand, from the viewpoint of the electrolyte resistance of the resin layer B, it is preferable that the resin layer B contains acid-modified polypropylene alone as a resin.

[0071] The polyester resin constituting the resin layer B is, for example, one that includes a polyester structure such as polyethylene terephthalate or polybutylene terephthalate. Furthermore, in addition to the polyethylene terephthalate structure or polybutylene terephthalate structure, the polyester may further include a polyether structure, which may have a polycondensation structure of at least one of polytetramethylene ether glycol and neopentyl glycol with terephthalic acid of a polybutylene terephthalate structure. Furthermore, in addition to the polyethylene terephthalate structure or polybutylene terephthalate structure, the polyester may further include another polyester structure, which may have a polycondensation structure of at least one selected from the group consisting of isophthalic acid, dodecanedioic acid, and sebacic acid with 1,4-butanediol of a polybutylene terephthalate structure.

[0072] The melting peak temperature of resin layer B is preferably 125° C. or higher, more preferably about 130° C. or higher, and even more preferably about 135° C. or higher. The melting peak temperature is, for example, 180° C. or lower, preferably 175° C. or lower, more preferably 170° C. or lower, even more preferably about 165° C. or lower, and even more preferably about 160° C. or lower. Preferred ranges of the melting peak temperature include about 125 to 180°C, about 125 to 175°C, about 125 to 170°C, about 125 to 165°C, about 125 to 160°C, about 130 to 180°C, about 130 to 175°C, about 130 to 170°C, about 130 to 165°C, about 130 to 160°C, about 135 to 180°C, about 135 to 175°C, about 135 to 170°C, about 135 to 165°C, and about 135 to 160°C.

[0073] Furthermore, when the adhesive film 1 for metal terminals of the present disclosure has a resin layer B as the first resin layer 12a, from the viewpoint of more suitably achieving the effects of the present disclosure, the thickness of the resin layer B is preferably about 10 μm or more, more preferably about 15 μm or more, even more preferably about 20 μm or more, even more preferably about 30 μm or more, even more preferably about 40 μm or more, even more preferably about 50 μm or more, even more preferably more than about 50 μm, even more preferably about 60 μm or more, and also preferably about 120 μm or less, more preferably about 100 μm or less, even more preferably 80 μm or less, even more preferably 50 μm or less. Preferred ranges of the thickness of the resin layer B are about 10 to 120 μm, about 10 to 100 μm, about 10 to 80 μm, about 10 to 50 μm, about 15 to 120 μm, about 15 to 100 μm, about 15 to 80 μm, about 15 to 50 μm, about 20 to 120 μm, about 20 to 100 μm, about 20 to 80 μm, about 20 to 50 μm, and about 30 to 120 μm. degrees, about 30 to 100 μm, about 30 to 80 μm, about 30 to 50 μm, about 40 to 120 μm, about 40 to 100 μm, about 40 to 80 μm, about 40 to 50 μm, about 50 to 120 μm, about 50 to 100 μm, about 50 to 80 μm, more than 50 μm and up to about 120 μm, more than 50 μm and up to about 100 μm, and more than 50 μm and up to about 80 μm.

[0074] Furthermore, when the adhesive film for metal terminal 1 of the present disclosure has a resin layer B as the intermediate layer 11, from the viewpoint of more suitably achieving the effects of the present disclosure, the thickness of the resin layer B is preferably about 10 μm or more, more preferably about 20 μm or more, and even more preferably about 30 μm or more. When the adhesive film for metal terminal 1 of the present disclosure is used in a relatively large power storage device such as a power storage device for a power storage system or an in-vehicle power storage device, the thickness of the resin layer B is preferably about 50 μm or more, even more preferably more than about 50 μm. Furthermore, from the viewpoint of more suitably achieving the effects of the present disclosure, the thickness of the resin layer B is preferably about 120 μm or less, more preferably about 110 μm or less, and even more preferably 100 μm or less. When the adhesive film for metal terminal 1 of the present disclosure is used in a relatively small power storage device such as a power storage device for a mobile phone, a smartphone power storage device, or a tablet terminal power storage device, the thickness of the resin layer B is preferably about 50 μm or less, even more preferably about 30 μm or less. Preferred ranges of the thickness of the resin layer B include about 10 to 120 μm, about 10 to 110 μm, about 10 to 100 μm, about 10 to 50 μm, about 10 to 30 μm, about 20 to 120 μm, about 20 to 110 μm, about 20 to 100 μm, about 20 to 50 μm, about 20 to 30 μm, about 30 to 120 μm, about 30 to 110 μm, about 30 to 100 μm, about 30 to 50 μm, about 50 to 120 μm, about 50 to 110 μm, about 50 to 100 μm, more than 50 μm and not more than 120 μm, more than 50 μm and not more than 110 μm, and more than 50 μm and not more than 100 μm.

[0075] The resin layer B may contain known additives (such as the above-mentioned fillers and pigments) in the same manner as the resin layer A. The types and amounts of fillers and pigments to be added are the same as those of the resin layer A.

[0076] From the viewpoint of more suitably achieving the effects of the present disclosure, the adhesive film 1 for a metal terminal has a total thickness of, for example, about 50 μm or more, preferably about 80 μm or more, more preferably about 90 μm or more, and even more preferably about 100 μm or more. The adhesive film 1 for a metal terminal of the present disclosure has a total thickness of about 500 μm or less, preferably about 300 μm or less, more preferably about 250 μm or less, even more preferably 200 μm or less, and even more preferably 180 μm or less. Preferred ranges of the total thickness of the adhesive film 1 for metal terminals of the present disclosure include about 50 to 500 μm, about 50 to 300 μm, about 50 to 250 μm, about 50 to 200 μm, about 50 to 180 μm, about 80 to 500 μm, about 80 to 300 μm, about 80 to 250 μm, about 80 to 200 μm, about 80 to 180 μm, about 90 to 500 μm, about 90 to 300 μm, about 90 to 250 μm, about 90 to 200 μm, about 90 to 180 μm, about 100 to 500 μm, about 100 to 300 μm, about 100 to 250 μm, about 100 to 200 μm, and about 100 to 180 μm. As a more specific example, when the adhesive film 1 for metal terminals of the present disclosure is used in a relatively small power storage device for a mobile phone, smartphone, or tablet, the total thickness is preferably about 60 to 100 μm, and when it is used in a relatively large power storage device for a power storage system or an in-vehicle power storage device, the total thickness is preferably about 100 to 200 μm.

[0077] From the viewpoint of more suitably achieving the effects of the present disclosure, the adhesive film 1 for metal terminals of the present disclosure has an adhesive strength (peel strength in a 25°C environment) to the heat-sealable resin layer of the exterior material, measured by the following method, of preferably about 60 N / 15 mm or more, more preferably about 70 N / 15 mm or more, and even more preferably about 80 N / 15 mm or more, and the upper limit of the adhesive strength (in a 25°C environment) is usually about 150 N / 15 mm or less, and preferred ranges include about 60 to 150 N / 15 mm, about 70 to 150 N / 15 mm, and about 80 to 150 N / 15 mm.

[0078] <Measurement of Adhesion Strength Between Adhesive Film and Sheathing Material (25°C Environment)> The adhesion strength (peel strength) between the adhesive film sheathing material and the metal terminal is measured according to the following procedure. (Preparation of Sheathing Material) First, a sheathing material for an electrical storage device (hereinafter sometimes simply referred to as "sheathing material") is prepared according to the following procedure. A substrate layer (30 μm thick) consisting of a polyethylene terephthalate film (12 μm thick), an adhesive layer (3 μm thick), and a nylon film (15 μm thick) is laminated on an aluminum alloy foil (40 μm thick) by dry lamination, and a heat-sealable resin layer is laminated on the other surface by coextrusion. Specifically, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to the nylon film to form an adhesive layer (3 μm thick) on the nylon film. Next, the adhesive layer and polyethylene terephthalate film are laminated on the nylon film to prepare a substrate layer. Next, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to one side of the barrier layer made of aluminum alloy foil, forming an adhesive layer (3 μm thick) on the aluminum alloy foil. Next, the adhesive layer and a substrate layer, with the nylon film side facing the adhesive surface, are laminated on the aluminum alloy foil, and then aging treatment is performed to produce a substrate layer / adhesive layer / barrier layer laminate. Next, an adhesive layer (40 μm thick, arranged on the metal layer side) made of maleic anhydride-modified polypropylene resin and a heat-sealable resin layer (40 μm thick, innermost layer) made of random polypropylene resin are co-extruded onto the barrier layer of the laminate, thereby laminating the adhesive layer / heat-sealable resin layer on the barrier layer, thereby obtaining an electrical storage device packaging material in which the substrate layer, adhesive layer, barrier layer, adhesive layer, and heat-sealable resin layer are laminated in this order. The degree of orientation of the heat-sealable resin layer of the resulting electrical storage device packaging material is 0.0 to 0.1.

[0079] Next, a 400 μm thick aluminum foil (JIS H4160:1994 A8079H-O) measuring 40 mm in MD, 22.5 mm in TD, and 400 μm in thickness is prepared as the metal terminal 2. The adhesive film 1 is cut to a length of 45 mm and a width of 20 mm. Next, as shown in the schematic diagram of FIG. 9 , the metal terminal is sandwiched between two adhesive films to obtain an adhesive film / metal terminal / adhesive film laminate. The MD and TD of the metal terminal are aligned with the length and width directions of the adhesive film, respectively, and the centers of the metal terminal and adhesive film are aligned (see FIG. 9( a)). The first resin layer of the adhesive film is positioned on the metal terminal side, and a second resin layer (resin layer A) is positioned on the outermost surface of the adhesive film sandwiching the metal terminal. Next, the laminate was sandwiched between two polytetrafluoroethylene films (PTFE films, 100 μm thick) and heated at 200 ° C, a surface pressure of 0.25 MPa, and for 16 seconds (one time) to heat-seal the first resin layer of the adhesive film to the metal terminal, producing a metal terminal with an adhesive film (see FIG. 9( b)). As shown in the schematic diagram of FIG. 9, the metal terminal was sandwiched between the adhesive films, so that the periphery of the metal terminal was covered with the adhesive film and a portion where the two adhesive films were heat-sealed to each other was formed. Next, the exterior material was cut to a size of 60 mm in TD and 200 mm in MD. As shown in the schematic diagram of FIG. 10, the exterior material was placed facing each other with the heat-sealable resin layers of the exterior material facing inward, and the resulting laminate was sandwiched between the opposing heat-sealable resin layers (see FIG. 10( a)). The exterior material was laminated so that the MD and TD of the exterior material coincided with the width and length directions of the laminate, respectively. In this state, a heat seal tester was used to heat seal the laminate at a width of 7 mm (7 mm in the y-axis direction in FIG. 10(b)), 200°C, a surface pressure of 1.0 MPa, and a duration of 1.5 seconds (see the hatched area S in FIG. 10(b)). The laminate was then naturally cooled to 25°C to obtain a laminate in which the exterior material and the adhesive film were heat-sealed (see FIG. 10(b)). Next, the central portion of the short side of the resulting laminate was cut to a width of 15 mm (see the two-dot dash line in FIG. 10(b) for the cutting position). Next, in a 25°C environment, the adhesive film and the heat-sealable resin layer of the exterior material were peeled off using a Tensilon universal testing machine.The maximum strength during peeling is defined as the peel strength (N / 15 mm) from the exterior material. The peeling speed is 20 mm / min, the peeling angle is 180°, and the chuck distance is 30 mm, and the average value is obtained by measuring three times.

[0080] The adhesive film for metal terminals of the present disclosure preferably has fine irregularities on at least one surface of the outermost layer. This can further improve adhesion to the heat-sealable resin layer 35 of the electrical storage device exterior material or the metal terminal. Methods for forming fine irregularities on the surface of the outermost layer of the adhesive film for metal terminals include adding additives such as fine particles to the outermost layer and shaping the film by contacting it with a cooling roll having an irregular surface. The fine irregularities preferably have a ten-point average roughness of the surface of the outermost layer of at least about 0.1 μm, more preferably at least about 0.2 μm, and are preferably at most about 35 μm, more preferably at most about 10 μm. Preferred ranges include about 0.1 to 35 μm, about 0.1 to 10 μm, about 0.2 to 35 μm, and about 0.2 to 10 μm. The ten-point average roughness is measured according to the method specified in JIS B0601:1994.

[0081] The adhesive film 1 for metal terminal of the present disclosure is preferably formed from a polyolefin resin. For example, the resin components contained in the adhesive film 1 for metal terminal of the present disclosure are preferably only an acid-modified polyolefin or only an acid-modified polyolefin and a polyolefin. The preferred acid-modified polyolefin and polyolefin are as described for the resin layer A and the resin layer B.

[0082] The adhesive film for metal terminal 1 of the present disclosure is preferably composed of a laminate including, in this order, a first resin layer 12 a, an intermediate layer 11, and a second resin layer 12 b. Hereinafter, a preferred embodiment of the adhesive film for metal terminal 1 of the present disclosure will be described in detail, taking as an example a case where the adhesive film for metal terminal 1 of the present disclosure is composed of a laminate including, in this order, at least a first resin layer 12 a, an intermediate layer 11, and a second resin layer 12 b, and the second resin layer 12 b is resin layer A.

[0083] When the adhesive film for metal terminal 1 of the present disclosure is disposed between the metal terminal 2 of the electricity storage device 10 and the exterior material for electricity storage devices 3, the surface of the metal terminal 2 made of metal and the heat-sealable resin layer 35 (a layer formed of a heat-sealable resin such as polyolefin) of the exterior material for electricity storage devices 3 are bonded via the adhesive film for metal terminal 1. The first resin layer 12a of the adhesive film for metal terminal 1 is disposed on the metal terminal 2 side, and the second resin layer 12b is disposed on the exterior material for electricity storage devices 3 side, with the first resin layer 12a in close contact with the metal terminal 2 and the second resin layer 12b in close contact with the heat-sealable resin layer 35 of the exterior material for electricity storage devices 3. The first resin layer 12a may be a single layer or a multilayer structure (multilayer). The second resin layer 12b may be a single layer or a multilayer structure (multilayer).

[0084] [First resin layer 12a and second resin layer 12b] As shown in Fig. 6, the adhesive film 1 for a metal terminal according to a preferred embodiment of the present disclosure comprises a first resin layer 12a on one side of the intermediate layer 11 and a second resin layer 12b on the other side. The first resin layer 12a is disposed on the metal terminal 2 side. The second resin layer 12b is disposed on the exterior material 3 for an electrical storage device. In the adhesive film 1 for a metal terminal according to the present disclosure, the first resin layer 12a and the second resin layer 12b are located on the surfaces of both sides, respectively.

[0085] In the present disclosure, the second resin layer 12b is formed of the aforementioned resin layer A. The first resin layer 12a may be formed of the aforementioned resin layer A or the aforementioned resin layer B.

[0086] The first resin layer 12a and the second resin layer 12b can each be formed, for example, from a resin film. When the first resin layer 12a and the second resin layer 12b are each formed from a resin film, when the first resin layer 12a and the second resin layer 12b are laminated with the intermediate layer 11 or the like to produce the adhesive film for a metal terminal 1 of the present disclosure, preformed resin films may be used as the first resin layer 12a and the second resin layer 12b, respectively. Alternatively, the resins forming the first resin layer 12a and the second resin layer 12b may be formed into films on the surface of the intermediate layer 11 or the like by extrusion molding, coating, or the like, to form the first resin layer 12a and the second resin layer 12b formed from resin films.

[0087] The first resin layer 12a disposed on the metal terminal 2 side preferably contains an acid-modified polyolefin as a primary component, and even more preferably an acid-modified polypropylene as a primary component. Here, "primary component" refers to a resin component contained in the first resin layer 12a whose content is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, "the first resin layer 12a contains an acid-modified polypropylene as a primary component" means that the acid-modified polypropylene content of the resin component contained in the first resin layer 12a is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0088] As described above, the second resin layer 12b preferably contains a polyolefin-based resin (i.e., has a polyolefin skeleton), preferably contains a polyolefin, and more preferably is a layer formed of a polyolefin. Among polyolefin-based resins, the second resin layer 12b preferably contains a polyolefin or an acid-modified polyolefin, more preferably contains a polyolefin (non-acid-modified polyolefin), and more preferably is a layer formed of a polyolefin (non-acid-modified polyolefin). The polyolefin-based resin is preferably a polypropylene-based resin. The polyolefin is preferably polypropylene, and the acid-modified polyolefin is preferably polypropylene.

[0089] The second resin layer 12b (resin layer A) disposed on the side of the electrical storage device sheathing material 3 preferably contains a polyolefin as a primary component, and even more preferably contains polypropylene as a primary component. Here, "primary component" refers to a resin component contained in the second resin layer 12b whose content is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, "the second resin layer 12b contains polypropylene as a primary component" refers to a resin component contained in the second resin layer 12b whose content is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0090] The melting peak temperature of the second resin layer 12b is preferably 110° C. or higher, more preferably about 120° C. or higher, and even more preferably about 130° C. or higher. From the same viewpoint, the melting peak temperature is, for example, 200° C. or lower, preferably 190° C. or lower, more preferably 180° C. or lower, even more preferably about 170° C. or lower, and even more preferably about 160° C. or lower. Preferred ranges of the melting peak temperature include about 110 to 200°C, about 110 to 190°C, about 110 to 180°C, about 110 to 170°C, about 110 to 160°C, about 120 to 200°C, about 120 to 190°C, about 120 to 180°C, about 120 to 170°C, about 120 to 160°C, about 130 to 200°C, about 130 to 190°C, about 130 to 180°C, about 130 to 170°C, and about 130 to 160°C.

[0091] To more effectively achieve the effects of the present disclosure, the thickness of the first resin layer 12a is preferably about 10 μm or more, more preferably about 15 μm or more, and even more preferably about 20 μm or more, and is preferably about 120 μm or less, more preferably about 100 μm or less, and even more preferably about 80 μm or less. Preferred ranges for the thickness of the first resin layer 12a include about 10 to 120 μm, about 10 to 100 μm, about 10 to 80 μm, about 15 to 120 μm, about 15 to 100 μm, about 15 to 80 μm, about 20 to 120 μm, about 20 to 100 μm, and about 20 to 80 μm.

[0092] Furthermore, from the viewpoint of more suitably achieving the effects of the present disclosure, the thickness of the second resin layer 12b is preferably about 10 μm or more, more preferably about 15 μm or more, and even more preferably about 20 μm or more, and is preferably about 120 μm or less, more preferably about 100 μm or less, and even more preferably about 80 μm or less. Preferred ranges for the thickness of the second resin layer 12b include about 10 to 120 μm, about 10 to 100 μm, about 10 to 80 μm, about 15 to 120 μm, about 15 to 100 μm, about 15 to 80 μm, about 20 to 120 μm, about 20 to 100 μm, and about 20 to 80 μm.

[0093] [Intermediate Layer 11 ] In the adhesive film for a metal terminal 1 , the intermediate layer 11 is a layer that functions as a support for the adhesive film for a metal terminal 1 .

[0094] The intermediate layer 11 may be formed from the resin layer A described above, or may be formed from the resin layer B described above.

[0095] The intermediate layer 11 can be formed, for example, from a resin film. When the intermediate layer 11 is formed from a resin film, a pre-formed resin film may be used as the intermediate layer 11 when the adhesive film for a metal terminal 1 of the present disclosure is manufactured by laminating the intermediate layer 11 with the first resin layer 12a or the like. Alternatively, the resin forming the intermediate layer 11 may be formed into a film on the surface of the first resin layer 12a or the like by extrusion molding, coating, or the like, to form the intermediate layer 11 formed from a resin film.

[0096] The material forming the intermediate layer 11 is not particularly limited. Examples of materials that can be used to form the intermediate layer 11 include polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicone resins, phenolic resins, polyetherimides, polyimides, polycarbonates, and mixtures or copolymers thereof. Among these, polyolefin resins are particularly preferred. That is, the material forming the intermediate layer 11 is preferably a resin containing a polyolefin skeleton, such as polyolefin or acid-modified polyolefin. The presence of a polyolefin skeleton in the resin constituting the intermediate layer 11 can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like.

[0097] As described above, the intermediate layer 11 preferably contains a polyolefin-based resin, preferably contains a polyolefin, and is more preferably a layer formed from a polyolefin. The polyolefin layer may be a stretched polyolefin film or an unstretched polyolefin film, but is preferably an unstretched polyolefin film. Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, polypropylene block copolymers (e.g., propylene and ethylene block copolymers), and polypropylene random copolymers (e.g., propylene and ethylene random copolymers); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred, and polypropylene is more preferred. Furthermore, due to its excellent electrolyte resistance, the intermediate layer 11 preferably contains homopolypropylene, is more preferably formed from homopolypropylene, and is even more preferably an unstretched homopolypropylene film.

[0098] Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (where I represents isophthalic acid and T represents terephthalic acid) containing structural units derived from terephthalic acid and / or isophthalic acid; and aromatic polyamides such as polymetaxylylene adipamide (MXD6); alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); polyamides copolymerized with a lactam component or an isocyanate component such as 4,4'-diphenylmethane-diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers, which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and copolymers thereof. These polyamides may be used alone or in combination of two or more.

[0099] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymer polyesters whose repeating units are primarily ethylene terephthalate, copolymer polyesters whose repeating units are primarily butylene terephthalate, etc. Specific examples of copolymer polyesters whose repeating units are primarily ethylene terephthalate include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decanedicarboxylate), etc. Specific examples of copolymer polyesters containing butylene terephthalate as the main repeating unit include copolymer polyesters in which butylene terephthalate is the main repeating unit and is polymerized with butylene isophthalate (hereinafter abbreviated as polybutylene (terephthalate / isophthalate)), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate, etc. These polyesters may be used alone or in combination of two or more.

[0100] Alternatively, the intermediate layer 11 may be formed of a nonwoven fabric made of the above-mentioned resin. When the intermediate layer 11 is a nonwoven fabric, it is preferable that the intermediate layer 11 is made of the above-mentioned polyolefin resin, polyamide resin, or the like.

[0101] The melting peak temperature of the intermediate layer 11 is preferably 120° C. or higher, more preferably about 130° C. or higher, and even more preferably about 140° C. or higher. From the same viewpoint, the melting peak temperature is, for example, 210° C. or lower, preferably 200° C. or lower, more preferably 190° C. or lower, even more preferably about 180° C. or lower, and even more preferably about 170° C. or lower. Preferred ranges of the melting peak temperature include about 120 to 210°C, about 120 to 200°C, about 120 to 190°C, about 120 to 180°C, about 120 to 170°C, about 130 to 210°C, about 130 to 200°C, about 130 to 190°C, about 130 to 180°C, about 130 to 170°C, about 140 to 210°C, about 140 to 200°C, about 140 to 190°C, about 140 to 180°C, and about 140 to 170°C.

[0102] The intermediate layer 11 may be a single layer or may have a multi-layer structure (multi-layer).

[0103] Furthermore, by blending a colorant into the intermediate layer 11, the intermediate layer 11 can be made a layer containing a colorant. Furthermore, light transmittance can be adjusted by selecting a resin with low transparency. When the intermediate layer 11 is a film, a colored film or a film with low transparency can be used. When the intermediate layer 11 is a nonwoven fabric, a nonwoven fabric using fibers or a binder containing a colorant, or a nonwoven fabric with low transparency can be used.

[0104] The colorant is not particularly limited, and a colorant capable of coloring the intermediate layer 11 can be suitably used. Specific examples of colorants include pigments. Various inorganic or organic pigments can be used as the pigment. Specific examples of pigments include the carbon (carbon, graphite), silica, titanium oxide, iron oxide, zinc oxide, magnesium oxide, and calcium oxide exemplified as fillers above, as well as inorganic oxides such as titanium nitride, zirconia black, copper oxide, cobalt oxide, and barium sulfate, and organic pigments such as quinacridone pigments, polyazo pigments, and isoindolinone pigments. Carbon (carbon, graphite) is a material commonly used inside electricity storage devices and is not likely to leach into the electrolyte solution. Furthermore, it has a strong coloring effect, and a sufficient coloring effect can be obtained even with an amount added that does not impair adhesion. Furthermore, it does not melt due to heat, and can increase the apparent melt viscosity of the added resin. Furthermore, it is possible to prevent the pressure-applied portion from becoming thin during heat fusion (heat sealing), thereby providing excellent sealing between the exterior packaging material for an electricity storage device and the metal terminal. The color of the colorant is preferably black, gray, or white.

[0105] When the intermediate layer 11 is made of a resin film, the surface of the intermediate layer 11 may be subjected to a known adhesion-facilitating treatment such as corona discharge treatment, ozone treatment, or plasma treatment, if necessary.

[0106] Furthermore, from the viewpoint of more suitably achieving the effects of the present disclosure, the thickness of the intermediate layer 11 is preferably about 20 μm or more, more preferably about 30 μm or more, even more preferably about 40 μm or more, and is preferably about 120 μm or less, more preferably about 110 μm or less, and even more preferably 100 μm or less. Preferred ranges for the thickness of the intermediate layer 11 include about 20 to 120 μm, about 20 to 110 μm, about 20 to 100 μm, about 30 to 120 μm, about 30 to 110 μm, about 30 to 100 μm, about 40 to 120 μm, about 40 to 110 μm, and about 40 to 100 μm.

[0107] From the same viewpoint, the ratio of the thickness of the intermediate layer 11 to the total thickness of the first resin layer 12a and the second resin layer 12b is preferably about 0.3 or more, more preferably about 0.4 or more, and preferably about 1.0 or less, more preferably about 0.8 or less, with preferred ranges being about 0.3 to 1.0, about 0.3 to 0.8, about 0.4 to 1.0, and about 0.4 to 0.8. Furthermore, from the viewpoint of improving the insulating properties of the adhesive film for metal terminal 1, the ratio is preferably about 0.55 or more, more preferably about 0.60 or more, and preferably about 1.0 or less, more preferably about 0.9 or less, with preferred ranges being about 0.55 to 1.0, about 0.55 to 0.9, about 0.60 to 1.0, and about 0.60 to 0.9.

[0108] Furthermore, if the total thickness of the adhesive film 1 for metal terminals is 100%, the proportion of the total thickness of the first resin layer 12a and the second resin layer 12b is preferably approximately 30 to 80%, and more preferably approximately 50 to 70%.

[0109] The adhesive film for metal terminal 1 of the present disclosure can be produced, for example, by laminating a first resin layer 12a and a second resin layer 12b, respectively, on both surfaces of an intermediate layer 11. The intermediate layer 11 can be laminated with the first resin layer 12a and the second resin layer 12b by a known method such as extrusion lamination, T-die lamination, inflation lamination, or thermal lamination.

[0110] The method for interposing the adhesive film 1 for a metal terminal between the metal terminal 2 and the exterior material 3 for an electricity storage device is not particularly limited, and for example, as shown in Figures 1 to 3, the adhesive film 1 for a metal terminal may be wrapped around the metal terminal 2 in the portion where the metal terminal 2 is sandwiched by the exterior material 3 for an electricity storage device. Furthermore, although not shown, in the portion where the metal terminal 2 is sandwiched by the exterior material 3 for an electricity storage device, the adhesive film 1 for a metal terminal may be arranged on both sides of the metal terminal 2 so as to cross the two metal terminals 2.

[0111] The adhesion promoter layer 13 is a layer provided as needed for the purpose of firmly adhering the intermediate layer 11 to the first resin layer 12a and the intermediate layer 11 to the second resin layer 12b (see FIG. 7). The adhesion promoter layer 13 may be provided on only one side between the intermediate layer 11 and the first resin layer 12a and between the intermediate layer 11 and the second resin layer 12b, or on both sides.

[0112] The adhesion promoter layer 13 can be formed using known adhesion promoters such as isocyanate-based, polyethyleneimine-based, polyester-based, polyurethane-based, and polybutadiene-based. From the viewpoint of obtaining strong adhesive strength, it is preferable to form the layer using an isocyanate-based adhesion promoter. Among these, isocyanate-based adhesion promoters, those containing an isocyanate component selected from triisocyanate monomer and polymeric MDI, have excellent laminate strength and show little deterioration in laminate strength at high temperatures. It is particularly preferable to form the adhesive layer using an adhesion promoter made of triphenylmethane-4,4',4"-triisocyanate, which is a triisocyanate monomer, or polymethylene polyphenyl polyisocyanate, which is a polymeric MDI (NCO content of about 30%, viscosity of 200 to 700 mPa·s). It is also preferable to form the adhesive layer using tris(p-isocyanatephenyl)thiophosphate, which is a triisocyanate monomer, or a two-component curing adhesion promoter that uses a polyethyleneimine-based compound as the main component and polycarbodiimide as the crosslinking agent.

[0113] The adhesion promoter layer 13 can be formed by coating and drying using a known coating method such as bar coating, roll coating, or gravure coating. The amount of the adhesion promoter to be applied is 20 to 100 mg / m when the adhesion promoter is made of triisocyanate. 2 about 40 to 60 mg / m 2 In the case of an adhesion promoter made of polymeric MDI, the concentration is 40 to 150 mg / m 2 about 60 to 100 mg / m 2 In the case of a two-component curing adhesion promoter that uses polyethyleneimine as the main component and polycarbodiimide as the crosslinking agent, the adhesive strength is about 5 to 50 mg / m 2about 10 to 30 mg / m 2 The triisocyanate monomer is a monomer having three isocyanate groups in one molecule, and polymeric MDI is a mixture of MDI and MDI oligomers formed by polymerizing MDI, and is represented by the following formula:

[0114]

[0115] In order to more suitably achieve the effects of the present invention, it is preferable that the first resin layer 12a and the intermediate layer 11 are in contact with each other, and that the second resin layer 12b and the intermediate layer 11 are in contact with each other.

[0116] Specific examples of preferred laminated structures for the adhesive film 1 for metal terminals of the present disclosure include a three-layer structure in which a first resin layer formed from acid-modified polypropylene / a base material formed from polypropylene / a second resin layer formed from acid-modified polypropylene are laminated in this order; and a three-layer structure in which a first resin layer formed from acid-modified polypropylene / a base material formed from polypropylene / a second resin layer formed from polypropylene are laminated in this order. Of these, the latter three-layer structure is particularly preferred in terms of adhesion between the heat-sealable resin layer 35 of the exterior material 3 for an electrical storage device and the second resin layer 12b.

[0117] [Metal Terminal 2] The adhesive film 1 for metal terminals of the present disclosure is used by being interposed between the metal terminal 2 and the exterior material 3 for an electricity storage device. The metal terminal 2 (tab) is a conductive member electrically connected to an electrode (positive electrode or negative electrode) of the electricity storage device element 4, and is made of a metal material. The metal material constituting the metal terminal 2 is not particularly limited, and examples include aluminum, nickel, copper, etc. For example, the metal terminal 2 connected to the positive electrode of a lithium ion electricity storage device is usually made of aluminum, etc. Furthermore, the metal terminal 2 connected to the negative electrode of a lithium ion electricity storage device is usually made of copper, nickel, etc.

[0118] From the viewpoint of enhancing electrolyte resistance, it is preferable that the surface of the metal terminal 2 is subjected to a chemical conversion treatment. For example, when the metal terminal 2 is formed of aluminum, specific examples of the chemical conversion treatment include known methods for forming a corrosion-resistant film using phosphates, chromates, fluorides, triazine thiol compounds, etc. Among the methods for forming a corrosion-resistant film, a chromate phosphate treatment using a compound consisting of three components: a phenolic resin, a chromium (III) fluoride compound, and phosphoric acid is preferred.

[0119] The size of the metal terminal 2 may be set appropriately depending on the size of the electricity storage device to be used. The thickness of the metal terminal 2 is preferably about 50 to 1000 μm, more preferably about 70 to 800 μm. The length of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm. The width of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm.

[0120] [Electricity Storage Device Exterior Material 3] The electricity storage device exterior material 3 may have a laminate structure made of a laminate having at least a base material layer 31, a barrier layer 33, and a heat-sealable resin layer 35 in this order. Fig. 8 shows an example of the cross-sectional structure of the electricity storage device exterior material 3, in which the base material layer 31, an optional adhesive layer 32, a barrier layer 33, an optional adhesive layer 34, and a heat-sealable resin layer 35 are laminated in this order. In the electricity storage device exterior material 3, the base material layer 31 is the outer layer side, and the heat-sealable resin layer 35 is the innermost layer. When assembling the electricity storage device, the heat-sealable resin layers 35 located on the peripheries of the electricity storage device elements 4 are brought into contact with each other and heat-sealed to seal the electricity storage device elements 4. 1 to 3 show an electricity storage device 10 using an embossed-type electricity storage device exterior material 3 formed by embossing or the like, but the electricity storage device exterior material 3 may also be an unformed pouch-type. Pouch types include three-sided seal, four-sided seal, and pillow type, and any of these types may be used.

[0121] The thickness of the laminate constituting the electrical storage device packaging material 3 is not particularly limited, but the upper limit, from the viewpoint of cost reduction, energy density improvement, etc., is, for example, about 190 μm or less, preferably about 180 μm or less, about 160 μm or less, about 155 μm or less, about 140 μm or less, about 130 μm or less, or about 120 μm or less; and the lower limit, from the viewpoint of maintaining the function of the electrical storage device packaging material 3 to protect the electrical storage device elements 4, is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, or about 80 μm or more; preferred ranges are, for example, about 35 to 190 μm, about 35 to 180 μm, or about 35 to 160 μm. degree, about 35 to 155 μm, about 35 to 140 μm, about 35 to 130 μm, about 35 to 120 μm, about 45 to 190 μm, about 45 to 180 μm, 45 ~160μm, 45-155μm, 45-140μm, 45-130μm, 45-120μm, 60-190μm, 60-180μm Examples include about 60 to 160 μm, about 60 to 155 μm, about 60 to 140 μm, about 60 to 130 μm, about 60 to 120 μm, about 80 to 190 μm, about 80 to 180 μm, about 80 to 160 μm, about 80 to 155 μm, about 80 to 140 μm, about 80 to 130 μm, and about 80 to 120 μm.

[0122] (Substrate Layer 31) In the packaging material for an electricity storage device 3, the substrate layer 31 is a layer that functions as a substrate of the packaging material for an electricity storage device, and is a layer that forms the outermost layer side.

[0123] The material for forming the substrate layer 31 is not particularly limited, as long as it has insulating properties. Examples of materials for forming the substrate layer 31 include polyester, polyamide, epoxy, acrylic resin, fluororesin, polyurethane, silicone resin, phenol, polyetherimide, polyimide, and mixtures or copolymers thereof. Polyesters such as polyethylene terephthalate and polybutylene terephthalate have the advantage of being highly resistant to electrolyte and being less susceptible to whitening due to adhesion of electrolyte, and are therefore preferably used as materials for forming the substrate layer 31. Furthermore, polyamide film has excellent stretchability and can prevent whitening due to resin cracking of the substrate layer 31 during molding, and is therefore preferably used as materials for forming the substrate layer 31.

[0124] The base layer 31 may be formed of a uniaxially or biaxially stretched resin film or an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, especially a biaxially stretched resin film, is preferably used as the base layer 31 because its heat resistance is improved by oriented crystallization.

[0125] Among these, the resin film forming the base layer 31 is preferably nylon or polyester, and more preferably biaxially oriented nylon or biaxially oriented polyester.

[0126] The base material layer 31 may be formed by laminating resin films made of different materials to improve pinhole resistance and insulation when used as a package for an electricity storage device. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated together, or a multilayer structure in which a biaxially oriented polyester film and a biaxially oriented nylon film are laminated together. When the base material layer 31 has a multilayer structure, the resin films may be bonded together via an adhesive, or may be laminated together directly without an adhesive. When the resin films are bonded together without an adhesive, examples of the methods that can be used include a coextrusion method, a sand lamination method, a thermal lamination method, and the like, in which the resin films are bonded together in a hot-melt state.

[0127] The base layer 31 may be made low-friction to improve formability. When making the base layer 31 low-friction, the coefficient of friction of the surface is not particularly limited, but may be, for example, 1.0 or less. To make the base layer 31 low-friction, for example, matte treatment, formation of a thin film layer of a slip agent, or a combination thereof may be used.

[0128] The thickness of the base layer 31 is, for example, about 10 to 50 μm, and preferably about 15 to 30 μm.

[0129] (Adhesive Layer 32) In the packaging material 3 for an electricity storage device, the adhesive layer 32 is a layer that is disposed on the base material layer 31 as necessary in order to impart adhesion to the base material layer 31. That is, the adhesive layer 32 is provided between the base material layer 31 and the barrier layer 33.

[0130] The adhesive layer 32 is formed of an adhesive capable of bonding the base material layer 31 and the barrier layer 33. The adhesive used to form the adhesive layer 32 may be a two-component curing adhesive or a one-component curing adhesive. The bonding mechanism of the adhesive used to form the adhesive layer 32 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, or the like.

[0131] The resin component of the adhesive that can be used to form the adhesive layer 32 is preferably a polyurethane-based two-component curing adhesive; polyamide, polyester, or a blend resin of these with modified polyolefin, from the viewpoint of having excellent ductility, durability under high humidity conditions, yellowing prevention, and thermal degradation prevention during heat sealing, and of effectively suppressing a decrease in the laminate strength between the base material layer 31 and the barrier layer 33 and preventing delamination.

[0132] Furthermore, the adhesive layer 32 may be multi-layered with different adhesive components. When the adhesive layer 32 is multi-layered with different adhesive components, it is preferable to select a resin that has excellent adhesion to the base material layer 31 as the adhesive component disposed on the base material layer 31 side, and an adhesive component that has excellent adhesion to the barrier layer 33 as the adhesive component disposed on the barrier layer 33 side, from the viewpoint of improving the laminate strength between the base material layer 31 and the barrier layer 33. When the adhesive layer 32 is multi-layered with different adhesive components, specifically, the adhesive component disposed on the barrier layer 33 side is preferably an acid-modified polyolefin, a metal-modified polyolefin, a mixed resin of polyester and acid-modified polyolefin, a resin containing a copolymer polyester, or the like.

[0133] The thickness of the adhesive layer 32 is, for example, about 2 to 50 μm, and preferably about 3 to 25 μm.

[0134] (Barrier Layer 33) In the electrical storage device packaging material 3, the barrier layer 33 is a layer that not only improves the strength of the electrical storage device packaging material but also has the function of preventing water vapor, oxygen, light, and the like from penetrating into the electrical storage device. The barrier layer 33 is preferably a metal layer, i.e., a layer formed of a metal. Specific examples of metals constituting the barrier layer 33 include aluminum, stainless steel, and titanium, and aluminum is preferred. The barrier layer 33 can be formed, for example, from a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, or a film provided with any of these vapor deposition films. It is preferably formed from a metal foil, and more preferably from an aluminum foil. From the viewpoint of preventing the occurrence of wrinkles or pinholes in the barrier layer 33 during the production of the exterior material for an electricity storage device, it is more preferable that the barrier layer be formed from a soft aluminum foil such as annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O).

[0135] The thickness of the barrier layer 33 is preferably about 10 to 200 μm, more preferably about 20 to 100 μm, about 20 to 45 μm, about 45 to 65 μm, or about 65 to 85 μm, from the viewpoint of making the exterior material for an electricity storage device thinner while making it less likely to produce pinholes during molding.

[0136] Furthermore, it is preferable that at least one surface, and preferably both surfaces, of the barrier layer 33 be chemically treated in order to stabilize adhesion, prevent dissolution and corrosion, etc. Here, chemical treatment refers to a treatment for forming a corrosion-resistant film on the surface of the barrier layer.

[0137] (Adhesive Layer 34) In the packaging material 3 for an electricity storage device, the adhesive layer 34 is a layer that is provided as needed between the barrier layer 33 and the heat-sealable resin layer 35 in order to firmly bond the heat-sealable resin layer 35.

[0138] The adhesive layer 34 is formed of an adhesive capable of bonding the barrier layer 33 and the heat-sealable resin layer 35. The composition of the adhesive used to form the adhesive layer is not particularly limited, but examples thereof include a resin composition containing an acid-modified polyolefin. Examples of acid-modified polyolefins include the same as those exemplified for the first resin layer 12 a and the second resin layer 12 b.

[0139] The thickness of the adhesive layer 34 is, for example, about 1 to 40 μm, and preferably about 2 to 30 μm.

[0140] (Heat-sealable resin layer 35) In the electrical storage device packaging material 3, the heat-sealable resin layer 35 corresponds to the innermost layer, and is a layer that seals the electrical storage device elements by heat-sealing the heat-sealable resin layers together when assembling the electrical storage device. The heat-sealable resin layer 35 is disposed on the outermost surface on the electrical storage device element side.

[0141] The resin component used in the heat-fusible resin layer 35 is not particularly limited as long as it is heat-fusible, and examples thereof include polyolefins and cyclic polyolefins.

[0142] Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred.

[0143] The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomer constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, preferred are cyclic alkenes, and more preferred are norbornene. Another example of the constituting monomer is styrene.

[0144] Among these resin components, preferred are crystalline or amorphous polyolefins, cyclic polyolefins, and blend polymers thereof; more preferred are polyethylene, polypropylene, copolymers of ethylene and norbornene, and blend polymers of two or more of these.

[0145] The heat-sealable resin layer 35 may be formed of a single resin component alone, or may be formed of a blend polymer of two or more resin components. The heat-sealable resin layer 35 may be formed of only one layer, or may be formed of two or more layers of the same or different resin components. It is particularly preferable that the second resin layer 12b and the heat-sealable resin layer 35 use the same resin, since this improves the adhesion between these layers.

[0146] The degree of orientation Q of the heat-fusible resin layer 35 is preferably in the range of 0.0 to 0.1.

[0147] The thickness of the heat-sealable resin layer 35 is not particularly limited, but may be about 2 to 2000 μm, preferably about 5 to 1000 μm, and more preferably about 10 to 500 μm. The thickness of the heat-sealable resin layer 35 is, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 34 described below is 10 μm or more, the thickness of the heat-sealable resin layer 35 is preferably about 85 μm or less, and more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 34 described below is less than 10 μm or when the adhesive layer 34 is not provided, the thickness of the heat-sealable resin layer 35 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[0148] The electrical storage device exterior material of the present disclosure can also be in the form of a kit including an electrical storage device exterior material for use in an electrical storage device and the adhesive film for a metal terminal of the present disclosure. In this case, the applicable electrical storage device also includes at least an electrical storage device element including a positive electrode, a negative electrode, and an electrolyte, an electrical storage device exterior material that encapsulates the electrical storage device element, and metal terminals electrically connected to the positive electrode and the negative electrode and protruding outside the electrical storage device exterior material. When used, the kit of the present disclosure is used such that the adhesive film for a metal terminal of the present disclosure is interposed between the metal terminal and the electrical storage device exterior material.

[0149] 2. Electricity Storage Device The electricity storage device 10 of the present disclosure comprises at least an electricity storage device element 4 including a positive electrode, a negative electrode, and an electrolyte, an exterior material for an electricity storage device 3 that seals the electricity storage device element 4, and metal terminals 2 that are electrically connected to the positive electrode and the negative electrode, respectively, and protrude to the outside of the exterior material for an electricity storage device 3. The electricity storage device 10 of the present disclosure is characterized in that an adhesive film for a metal terminal 1 of the present disclosure is interposed between the metal terminal 2 and the exterior material for an electricity storage device 3. In other words, the electricity storage device 10 of the present disclosure can be manufactured by a method that includes a step of interposing an adhesive film for a metal terminal 1 of the present disclosure between the metal terminal 2 and the exterior material for an electricity storage device 3.

[0150] Specifically, an electricity storage device element 4 including at least a positive electrode, a negative electrode, and an electrolyte is enclosed in an electricity storage device exterior material 3, with metal terminals 2 connected to the positive and negative electrodes protruding outward, and the adhesive film 1 for metal terminals of the present disclosure is interposed between the metal terminals 2 and the heat-sealable resin layer 35, and the electricity storage device element 4 is covered around its periphery so as to form a flange portion (a region where the heat-sealable resin layers 35 contact each other, i.e., the peripheral portion 3a of the electricity storage device exterior material 3), and the heat-sealable resin layers 35 of the flange portion are heat-sealed to provide an electricity storage device 10 using the electricity storage device exterior material 3. When the electricity storage device element 4 is housed using the electricity storage device exterior material 3, the heat-sealable resin layer 35 of the electricity storage device exterior material 3 is used so that it faces inside (the surface in contact with the electricity storage device element 4).

[0151] The electricity storage device element may be sealed with a lid in addition to the electricity storage device exterior material. That is, the electricity storage device exterior material and the lid constitute an exterior (an exterior for an electricity storage device) that seals the electricity storage device element. For example, the electricity storage device element may be housed inside a cylindrically configured electricity storage device exterior material, and the opening may be closed with the lid. In another example, the electricity storage device element connected to the lid may be housed inside a cylindrically configured electricity storage device exterior material that has an opening, and the opening may be closed with the lid. The lid and the electricity storage device exterior material are preferably joined by any means. From the viewpoint of reducing dead space between the electricity storage device element and the electricity storage device exterior material to improve the volumetric energy density of the electricity storage device, the electricity storage device exterior material is preferably wrapped around the electricity storage device element and the lid.

[0152] The lid body can be formed, for example, from a resin molded product, a metal molded product, an exterior material for an electricity storage device, or a combination thereof. In this disclosure, when the lid body is referred to as a resin molded product, this does not include an embodiment in which the lid body is formed solely from a film defined by JIS K6900-1994 [Plastics - Terminology]. When the lid body is a metal molded product, the lid body also functions as a metal terminal, so the metal terminal can be omitted. The lid body may be formed from a resin material and a conductive material.

[0153] The exterior material for an electricity storage device of the present disclosure can be suitably used in electricity storage devices such as batteries (including condensers, capacitors, etc.). The exterior material for an electricity storage device of the present disclosure may be used in either primary or secondary batteries, but is preferably used in secondary batteries. The type of secondary battery to which the exterior material for an electricity storage device of the present disclosure is applied is not particularly limited, and examples include lithium ion batteries, lithium ion polymer batteries, all-solid-state batteries, semi-solid batteries, quasi-solid batteries, polymer batteries, all-resin batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for the exterior material for an electricity storage device of the present disclosure.

[0154] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the examples.

[0155] <Production of adhesive film> Examples 1 and 3 Using an extruder and a T-die casting machine, polypropylene (PP layer, melting peak temperature 140°C) was extruded to a thickness of 40 μm onto one side of a carbon black-containing polypropylene (PP layer, homopolypropylene, melting peak temperature 160°C, thickness 60 μm) as an intermediate layer, as a second resin layer (resin layer A) on the exterior material side, and maleic anhydride-modified polypropylene (PP layer, melting peak temperature 140°C) was extruded to a thickness of 50 μm onto the other side as a first resin layer on the metal terminal side, to obtain an adhesive film (total thickness 150 μm) in which the first resin layer (PP layer, melting peak temperature 140°C, thickness 50 μm) / substrate (PP layer, melting peak temperature 160°C, thickness 60 μm) / second resin layer (resin layer A, PP layer, melting peak temperature 140°C, thickness 40 μm) were laminated in this order. In Examples 1 and 3, the resin layer A was extruded under standard film-forming temperature conditions, standard film-forming speed conditions, and standard cooling conditions, thereby adjusting the degree of orientation.

[0156] Examples 5 and 6 Using an extruder and a T-die casting machine, a polypropylene film (PP layer (polypropylene layer), polypropylene, melting peak temperature 160 ° C., thickness 70 μm) as a polypropylene layer containing titanium oxide as a gray colored layer, and a maleic anhydride-modified polypropylene (r-PPA layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 ° C.) as a first resin layer on the metal terminal side were extruded to a thickness of 70 μm, and on the other side, a polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 ° C.) was extruded to a thickness of 60 μm as a second resin layer (resin layer A) on the exterior material side, and an adhesive film (total thickness 200 μm) in which the second resin layer (resin layer A, r-PP layer (random polypropylene layer), thickness 60 μm) / polypropylene layer (PP layer, thickness 70 μm) / first resin layer (r-PPA layer, thickness 70 μm) was laminated in this order was obtained. In Example 5, in the extrusion molding of the resin layer A, the film formation temperature was lowered and the film formation rate and chill roll temperature were increased based on the standard film formation temperature conditions, film formation rate conditions, and cooling rate conditions of Examples 1 and 3. On the other hand, in Example 6, in the extrusion molding of the resin layer A, the film formation temperature and film formation rate were lowered and the chill roll temperature was increased based on the standard film formation temperature conditions, film formation rate conditions, and cooling rate conditions of Examples 1 and 3.

[0157] Examples 2, 4, and 7 Using an extruder and a T-die casting machine, polypropylene (PP layer, homopolypropylene, melting peak temperature 163 ° C., thickness 50 μm) was extruded onto one side of the intermediate layer of polypropylene (PP layer, homopolypropylene, melting peak temperature 163 ° C., thickness 50 μm) as the second resin layer (resin layer A) on the exterior material side, and carbon black-containing maleic anhydride-modified polypropylene (PPa layer, melting peak temperature 140 ° C.) was extruded onto the other side as the first resin layer on the metal terminal side, each to a thickness of 50 μm, to obtain an adhesive film (total thickness 150 μm) in which the first resin layer (PP layer, melting peak temperature 140 ° C., thickness 50 μm) / substrate (PP layer, melting peak temperature 163 ° C., thickness 50 μm) / second resin layer (resin layer A, PP layer, melting peak temperature 140 ° C., thickness 50 μm) was laminated in this order. In Examples 2, 4, and 7, the film-forming temperature and film-forming rate were increased and the chill roll temperature was decreased in the extrusion molding of resin layer A, based on the standard film-forming temperature conditions, film-forming rate conditions, and cooling rate conditions of Examples 1 and 3, respectively.

[0158] Example 8-11 Using an extruder and a T-die casting machine, on one side of a carbon black-containing polypropylene (PP layer, homopolypropylene, melting peak temperature 160 ° C., thickness 60 μm) as an intermediate layer, polypropylene (resin layer A, PP layer, melting peak temperature 140 ° C.) was extruded to a thickness of 40 μm as a second resin layer on the exterior material side, and on the other side, maleic anhydride-modified polypropylene (PPa layer, melting peak temperature 140 ° C.) was extruded to a thickness of 50 μm as a first resin layer on the metal terminal side, and an adhesive film (total thickness 150 μm) in which the first resin layer (PPa layer, melting peak temperature 140 ° C., thickness 50 μm) / substrate (PP layer, melting peak temperature 160 ° C., thickness 60 μm) / second resin layer (resin layer A, PP layer, melting peak temperature 140 ° C., thickness 40 μm) was laminated in order was obtained. The second resin layer, which was used as resin layer A, was produced under conditions of a lower film-forming temperature than the standard, a faster film-forming speed than the standard, and a slower cooling rate than the standard cooling rate, thereby adjusting the degree of orientation.

[0159] Examples 12, 14, 16, 18, Comparative Example 1-2 Using an inflation extrusion device, on one side of the polypropylene (PP layer, homopolypropylene, melting peak temperature 160 ° C., thickness 80 μm) as an intermediate layer, maleic anhydride-modified polypropylene (PPa layer, melting peak temperature 140 ° C.) as the second resin layer (resin layer A) on the exterior material side, and on the other side, maleic anhydride-modified polypropylene (PPa layer, melting peak temperature 140 ° C.) as the first resin layer on the metal terminal side, each with a thickness of 35 μm, and an adhesive film (total thickness 150 μm) in which the first resin layer (PPa layer, melting peak temperature 140 ° C., thickness 35 μm) / substrate (PP layer, melting peak temperature 160 ° C., thickness 80 μm) / second resin layer (resin layer A, PPa layer, melting peak temperature 140 ° C., thickness 35 μm) was extruded in that order. The second resin layer, which was designated as resin layer A, was produced under conditions of a lower film-forming temperature than the standard, a film-forming speed that was significantly slower than the standard, and cooling that was significantly slower than the standard cooling, thereby adjusting the degree of orientation.

[0160] Examples 13, 15, and 17 Using an inflation extrusion device, a polypropylene (PP layer, homopolypropylene, melting peak temperature 160°C, thickness 30µm) intermediate layer was formed on one side thereof with a random polypropylene (PP layer, random polypropylene, melting peak temperature 140°C, thickness 25µm) and a maleic anhydride-modified polypropylene (PP layer, random polypropylene, melting peak temperature 140°C, thickness 35µm) as a second resin layer (resin layer A) on the exterior material side, and a random polypropylene (PP layer, random polypropylene) was formed on the other side thereof. A first resin layer (PP layer, peak melting temperature 140°C, thickness 25 μm) on the metal terminal side was extruded, and a maleic anhydride-modified polypropylene (PP layer, peak melting temperature 140°C, thickness 35 μm) on the metal terminal side was extruded to obtain an adhesive film (total thickness 150 μm) in which the first resin layer (PP layer, peak melting temperature 140°C, thickness 35 μm) / connecting layer (PP layer, peak melting temperature 140°C, thickness 25 μm) / base material (PP layer, peak melting temperature 160°C, thickness 30 μm) / connecting layer (PP layer, peak melting temperature 140°C, thickness 25 μm) / second resin layer (resin layer A, PPa layer, peak melting temperature 140°C, thickness 35 μm) were laminated in this order. The second resin layer, which was designated as resin layer A, was produced under conditions of a lower film-forming temperature than the standard, a film-forming speed that was significantly slower than the standard, and cooling that was significantly slower than the standard cooling, thereby adjusting the degree of orientation.

[0161] Example 19 Using an extruder and a T-die casting machine, polypropylene (PP layer, homopolypropylene, melting peak temperature 163 ° C., thickness 50 μm) as an intermediate layer was extruded on one side as a second resin layer (resin layer A) on the exterior material side (PP layer, melting peak temperature 140 ° C.), and carbon black-containing maleic anhydride-modified polypropylene (PP layer, melting peak temperature 140 ° C.) was extruded on the other side as a first resin layer (resin layer A) on the metal terminal side, each to a thickness of 75 μm, to obtain an adhesive film (total thickness 200 μm) in which the first resin layer (PP layer, melting peak temperature 140 ° C., thickness 75 μm) / substrate (PP layer, melting peak temperature 163 ° C., thickness 50 μm) / second resin layer (resin layer A, PP layer, melting peak temperature 140 ° C., thickness 75 μm) was laminated in this order.

[0162] <Measurement of the orientation degree P of the resin layer A of the adhesive film and the orientation degree Q of the heat-sealable resin layer of the packaging material> The other surface of an adhesive film (MD 25 mm, TD 20 mm) having a resin layer A constituting one surface was heat-sealed to a metal terminal (length 22.5 mm, width 30 mm, thickness 0.4 mm) at a temperature of 200 ° C., a pressure of 0.25 MPa, and for 16 seconds (one time). A metal terminal with an adhesive film arranged so that the resin layer A was located on the surface was obtained and used as a measurement sample. At this time, the MD of the adhesive film and the longitudinal direction of the metal terminal were aligned. Furthermore, in the state of the metal terminal with an adhesive film for a metal terminal, the resin layer A was arranged on the outermost surface. Pole measurements were performed on the resin layer A of the metal terminal with an adhesive film and the heat-sealable resin layer of the packaging material for an electric storage device described below using a Rigaku X-ray diffraction measurement device SmartLab under the following measurement conditions. Next, from the obtained diffraction intensity spectrum, the orientation degree P of the resin layer A of the metal terminal with adhesive film and the orientation degree Q of the heat-sealable resin layer of the exterior material for an electricity storage device (each heat-sealable resin layer had an orientation degree Q in the range of 0.000 to 0.100) were measured under the following analysis conditions. Note that in Examples 1, 2, 8, 12, 13, 18, and 19, the same heat-sealable resin layer (orientation degree before heat-sealing with the adhesive film was 0.043), in Examples 3 to 6, 9, 14, and 15, the same heat-sealable resin layer (orientation degree before heat-sealing with the adhesive film was 0.033), in Examples 7, 11, 16, and 17, the same heat-sealable resin layer (orientation degree before heat-sealing with the adhesive film was 0.019), and in Example 10 and Comparative Examples 1 and 2, the same heat-sealable resin layer (orientation degree before heat-sealing with the adhesive film was 0.026) was used.

[0163] <Orientation degree of resin layer A of adhesive film before heat fusion> The orientation degree of resin layer A of adhesive film before heat fusion was measured in the same manner as the orientation degree P of resin layer A of adhesive film described above, except that the measurement object was the surface of resin layer A of adhesive film before heat fusion.

[0164] (Measurement Conditions) After performing pole measurement under the following measurement conditions, the degrees of orientation P and Q of the resin layer A and the heat-fusible resin layer, and the absolute value of their difference |P−Q| are determined from the obtained diffraction intensity spectrum under the following analysis conditions.

[0165] X-rays: CuKα rays (1.548 Å) Tube voltage: 45 kV Tube current: 200 mA Optical system: Inplane pole measurement Entrance slit: 5 mm 2θ angle: 16.8° (PP 040 plane) Detector: Scintillation counter Sample form: The film was cut into a circle with a diameter of 2 cm and placed with the fused surface facing upwards. In the sample of the exterior material for an electricity storage device, the fused surface is the surface made up of the heat-sealable resin layer, and in the sample of the metal terminal with adhesive film, it is the surface made up of resin layer A.

[0166] <Analysis Conditions> After integrating the spectral intensity for an α angle of 0° to 30° (the horizontal direction of the sample is taken as 0°), the average spectral intensity for a β angle of 70° to 110° and 250° to 290° (the MD direction of the sample is taken as 0°) and the average spectral intensity for a β angle of 0° to 20°, 160° to 200°, and 340° to 360° are calculated, and these are designated as S1 and S2, respectively. From the obtained average spectral intensities S1 and S2, a quantity defined as |(S1-S2) / (S1+S2)| is calculated, and this is taken as the degree of orientation. The degree of orientation of resin layer A is designated as P, the degree of orientation of the heat-fusible resin layer is designated as Q, and the absolute value of the difference between the two, |P-Q|, is calculated.

[0167] <Melting ratio (volume %) and melting temperature (°C) of adhesive film> According to the following procedure, the adhesive film was heated to 210°C to melt, and cooled from 210°C at a temperature decrease rate of 10°C / min, and the temperatures when the adhesive film was 90% by volume melted, 75% by volume melted, 50% by volume melted, 25% by volume melted, and 10% by volume melted were measured. The results are shown in Table 1.

[0168] The heat of fusion of each measurement sample is measured in accordance with the provisions of JIS K 7122:2012. Measurements are performed using a differential scanning calorimeter (DSC, TA Instruments Q200 differential scanning calorimeter). The measurement sample is held at -50°C for 15 minutes, then heated from -50°C to 210°C at a heating rate of 10°C / min, and the first heat of fusion ΔH (J / g) is measured, and then held at 210°C for 10 minutes. Next, the temperature is lowered from 210°C to -50°C at a heating rate of 10°C / min and held for 15 minutes. Furthermore, the temperature is raised from -50°C to 210°C at a heating rate of 10°C / min, and the second heat of fusion ΔH (J / g) is measured. The flow rate of nitrogen gas is 50 ml / min. The value of the heat of fusion ΔH (J / g) measured the first time using the above procedure is adopted. The heat of fusion is the melting peak area surrounded by the peak and the baseline (the straight line connecting the 80°C point on the DSC curve to the 170°C point). On the other hand, the heat of fusion of crystals in a temperature range below X°C is calculated from the area of ​​the temperature range below X°C in the melting peak area when calculating the total heat of fusion of crystals. In other words, the "melting fraction at temperature X°C" is a value calculated from the following formula: Melting fraction at temperature X°C (%) = {(area of ​​the melting peak area in the temperature range below temperature X) / (melting peak area)} × 100 ... formula Therefore, the temperature at 25% by volume melting is the temperature X°C at which the melting fraction at temperature X (melting fraction (volume %)) = 25.

[0169] <Measurement of Adhesion Strength Between Adhesive Film and Exterior Material (25°C Environment)> The adhesion strength (peel strength) between the adhesive film exterior material and the metal terminal was measured using the following procedure. The results are shown in Table 1. (Preparation of Exterior Material) First, an exterior material for an electricity storage device (hereinafter sometimes simply referred to as "exterior material") was prepared using the following procedure. A substrate layer (30 μm thick) consisting of a polyethylene terephthalate film (12 μm thick), an adhesive layer (3 μm thick), and a nylon film (15 μm thick) was laminated on an aluminum alloy foil (40 μm thick) using a dry lamination method, and a heat-sealable resin layer was laminated on the other surface by coextrusion. Specifically, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to the nylon film to form an adhesive layer (3 μm thick) on the nylon film. Next, the adhesive layer and a polyethylene terephthalate film were laminated on the nylon film to prepare a substrate layer. Next, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one side of a barrier layer made of aluminum alloy foil to form an adhesive layer (3 μm thick) on the aluminum alloy foil. Next, the adhesive layer and a substrate layer, with the nylon film side facing the adhesive surface, were laminated on the aluminum alloy foil, and then aging treatment was performed to produce a substrate layer / adhesive layer / barrier layer laminate. Next, an adhesive layer (40 μm thick, arranged on the metal layer side) made of maleic anhydride-modified polypropylene resin and a heat-sealable resin layer (40 μm thick, innermost layer) made of random polypropylene resin were co-extruded on the barrier layer of the laminate to laminate the adhesive layer / heat-sealable resin layer on the barrier layer, thereby obtaining an exterior packaging material for an electricity storage device in which the substrate layer, adhesive layer, barrier layer, adhesive layer, and heat-sealable resin layer were laminated in this order. In addition, in Examples 1, 2, 8, 12, 13, 18, and 19, the same heat-sealable resin layer (with an orientation degree of 0.043 before heat-sealing with the adhesive film) was used, in Examples 3 to 6, 9, 14, and 15, the same heat-sealable resin layer (with an orientation degree of 0.033 before heat-sealing with the adhesive film) was used, in Examples 7, 11, 16, and 17, the same heat-sealable resin layer (with an orientation degree of 0.019 before heat-sealing with the adhesive film) was used, and in Example 10 and Comparative Examples 1 and 2, the same heat-sealable resin layer (with an orientation degree of 0.026 before heat-sealing with the adhesive film) was used.

[0170] Next, aluminum foil (JIS H4160:1994 A8079H-O) with an MD of 40 mm, TD of 22.5 mm, and thickness of 400 μm was prepared as the metal terminal 2. Each adhesive film 1 obtained in the Examples and Comparative Examples was cut to a length of 45 mm and a width of 20 mm. Next, as shown in the schematic diagram of Figure 9, a metal terminal was sandwiched between two adhesive films to obtain an adhesive film / metal terminal / adhesive film laminate. The metal terminal was laminated so that the MD and TD of the metal terminal were aligned with the length and width directions of the adhesive film, respectively, and the centers of the metal terminal and adhesive film were aligned (see Figure 9(a)). The first resin layer of the adhesive film for metal terminals was positioned on the metal terminal side. Next, the laminate was sandwiched between two polytetrafluoroethylene films (PTFE films, 100 μm thick) and heated at 200 °C, a surface pressure of 0.25 MPa, and a duration of 16 seconds (one cycle). The first resin layer of the adhesive film was heat-sealed to the metal terminal to produce a metal terminal with an adhesive film (see FIG. 9(b)). As shown in the schematic diagram of FIG. 9, the metal terminal was sandwiched between the adhesive films, resulting in the metal terminal being covered with the adhesive film and the two adhesive films being heat-sealed to each other. Next, the exterior material was cut to a size of 60 mm in TD and 200 mm in MD. As shown in the schematic diagram of FIG. 10, the exterior material was placed facing each other with the heat-sealable resin layers of the exterior material facing inward, and the resulting laminate was sandwiched between the opposing heat-sealable resin layers (see FIG. 10(a)). The exterior material was laminated so that the MD and TD of the exterior material coincided with the width and length directions of the laminate, respectively. In this state, a heat seal tester was used to perform heat sealing at a width of 7 mm (7 mm in the y-axis direction in FIG. 10(b)), 200°C, a surface pressure of 1.0 MPa, and a time of 1.5 seconds (see the hatched area S in FIG. 10(b)), and the laminate was naturally cooled to 25°C to obtain a laminate in which the packaging material and the adhesive film were heat-sealed (see FIG. 10(b)). Next, the central portion of the short side of the obtained laminate was cut to a width of 15 mm (see the two-dot dash line in FIG. 10(b) for the cutting position).Next, in an environment of 25°C, one end of each exterior material was chucked on top, and the metal terminal with the adhesive film for the metal terminal was chucked on the bottom, and the adhesive film and the heat-sealable resin layer of the exterior material were peeled off using a Tensilon universal material testing machine (RTG-1210 manufactured by A&D Co., Ltd.). The maximum strength at the time of peeling was taken as the peel strength (N / 15 mm) to the exterior material. The peel speed was 20 mm / min, the peel angle was 180°, and the chuck distance was 30 mm, and the average value was taken from three measurements. The evaluation indices A, B, and C are as follows: A: 80 N / 15 mm or more B: 60 N / 15 mm or more but less than 80 N / 15 mm C: Less than 60 N / 15 mm.

[0171]

[0172] As described above, the present disclosure provides the following aspects of the invention. Item 1. An adhesive film for metal terminals that is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element, wherein the exterior material for an electricity storage device comprises a heat-sealable resin layer that is arranged on the outermost surface facing the electricity storage device element, and the adhesive film for metal terminal comprises a resin layer A that constitutes one of the surfaces, and the adhesive film for metal terminals and the metal terminal are heat-sealed together under conditions of a temperature of 200°C, a pressure of 0.25 MPa, and a time period of 16 seconds to obtain a metal terminal with an adhesive film for metal terminal that is arranged so that the resin layer A is located on the surface, and the absolute value |P-Q| of the difference between the degree of orientation P measured for the resin layer A of the metal terminal with the adhesive film for metal terminal and the degree of orientation Q of the heat-sealable resin layer having an orientation degree of 0.000 to 0.100 is 0.200 or less. Item 1. The adhesive film for metal terminal according to Item 1, which contains a polyolefin skeleton. Item 3. The adhesive film for metal terminal according to Item 1 or 2, which has a multilayer structure. Item 4. The adhesive film for metal terminal according to any one of Items 1 to 3, which is composed of a laminate including, in this order, a first resin layer disposed on the metal terminal side, an intermediate layer, and a second resin layer disposed on the electrical storage device sheathing material side. Item 5. The adhesive film for metal terminal according to Item 4, wherein the second resin layer disposed on the electrical storage device sheathing material side is resin layer A. Item 6. The adhesive film for metal terminal according to any one of Items 1 to 5, wherein the 25% by volume melting temperature of resin layer A is 102°C or less. Item 7. The adhesive film for metal terminal according to any one of Items 1 to 6, which has a thickness of 100 μm or more.Item 8. A method for producing an adhesive film for a metal terminal, the adhesive film being interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element, wherein the exterior material for an electricity storage device comprises a heat-sealable resin layer that is disposed on the outermost surface on the electricity storage device element side, and a resin layer A that constitutes one surface of the adhesive film for a metal terminal and the metal terminal are heat-sealed under conditions of a temperature of 200°C, a pressure of 0.25 MPa, and a time period of 16 seconds to obtain a metal terminal with an adhesive film for a metal terminal that is disposed so that the resin layer A is located on the surface, and the absolute value |P-Q| of the difference between the degree of orientation P measured for the resin layer A of the metal terminal with the adhesive film for a metal terminal and the degree of orientation Q of a heat-sealable resin layer having an orientation degree of 0.000 to 0.100 is 0.200 or less. a metal terminal with an adhesive film for a metal terminal, the metal terminal having an adhesive film for a metal terminal attached to it, wherein the metal terminal is used so as to be electrically connected to an electrode of an electricity storage device element, the adhesive film for a metal terminal is used so as to be interposed between the metal terminal and an exterior material for an electricity storage device that seals the electricity storage device element, the exterior material for an electricity storage device having a heat-sealable resin layer that is disposed on the outermost surface on the electricity storage device element side, and the metal terminal with an adhesive film for a metal terminal, wherein the absolute value |P-Q| of the difference between the degree of orientation P measured for resin layer A that constitutes the surface of the adhesive film for a metal terminal of the metal terminal with an adhesive film for a metal terminal and the degree of orientation Q of a heat-sealable resin layer having an orientation degree of 0.000 to 0.100 is 0.200 or less.Item 10. An electricity storage device comprising: an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an exterior material for an electricity storage device that seals the electricity storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding to the outside of the exterior material for an electricity storage device, wherein the exterior material for an electricity storage device is composed of a laminate comprising at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, the heat-sealable resin layer having a degree of orientation Q; an adhesive film for metal terminal is interposed between the metal terminal and the heat-sealable resin layer of the exterior material for an electricity storage device, and the absolute value |P-Q| of the difference between the degree of orientation P measured for resin layer A that constitutes one surface of the adhesive film for metal terminal and the degree of orientation Q of the heat-sealable resin layer is 0.200 or less. Item 11. An electrical storage device packaging material for use in an electrical storage device, wherein the electrical storage device comprises: an electrical storage device element having at least a positive electrode, a negative electrode, and an electrolyte; the electrical storage device packaging material sealing the electrical storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding to the outside of the electrical storage device packaging material, wherein an adhesive film for metal terminal is interposed between the metal terminal and the electrical storage device packaging material, wherein the adhesive film for metal terminal is the adhesive film for metal terminal according to any one of items 1 to 7, and the electrical storage device packaging material is composed of a laminate including at least a base layer, a barrier layer, and a heat-sealable resin layer in this order. Item 8. A kit comprising an exterior material for an electricity storage device for use in an electricity storage device and the adhesive film for a metal terminal according to any one of Items 1 to 7, wherein the electricity storage device comprises an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte, the exterior material for an electricity storage device that seals the electricity storage device element, and the metal terminals that are electrically connected to the positive electrode and the negative electrode, respectively, and protrude outside the exterior material for an electricity storage device, and the kit is used such that the adhesive film for a metal terminal is interposed between the metal terminal and the exterior material for an electricity storage device during use.Item 13. A kit comprising an exterior material for an electricity storage device for use in an electricity storage device and the metal terminal with an adhesive film for a metal terminal according to Item 9, wherein the electricity storage device comprises an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte, the exterior material for an electricity storage device sealing the electricity storage device element, and metal terminals with the adhesive film for a metal terminal electrically connected to each of the positive electrode and the negative electrode and protruding to the outside of the exterior material for an electricity storage device, the exterior material for an electricity storage device being composed of a laminate comprising at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, and the kit is used such that, during use, the metal terminal with the adhesive film for a metal terminal is interposed between the heat-sealable resin layers of the exterior material for an electricity storage device.

[0173] REFERENCE SIGNS LIST 1 adhesive film for metal terminal 2 metal terminal 3 packaging material for electricity storage device 3a peripheral portion of packaging material for electricity storage device 4 electricity storage device element 10 electricity storage device 11 intermediate layer 12a first resin layer 12b second resin layer 31 substrate layer 32 adhesive layer 33 barrier layer 34 adhesive layer 35 heat-sealable resin layer

Claims

1. An adhesive film for metal terminal interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element, wherein the exterior material for an electricity storage device comprises a heat-sealable resin layer disposed on the outermost surface on the electricity storage device element side, and the adhesive film for metal terminal comprises a resin layer A that constitutes the surface of one side, and the adhesive film for metal terminal and the metal terminal are heat-sealed under conditions of a temperature of 200°C, a pressure of 0.25 MPa, and a time period of 16 seconds to obtain a metal terminal with an adhesive film for metal terminal disposed so that the resin layer A is located on the surface, and the absolute value |P-Q| of the difference between the degree of orientation P measured for the resin layer A of the metal terminal with the adhesive film for metal terminal and the degree of orientation Q of the heat-sealable resin layer having an orientation degree of 0.000 to 0.100 is 0.200 or less.

2. The adhesive film for metal terminals according to claim 1, which comprises a polyolefin skeleton.

3. An adhesive film for metal terminals according to claim 1 or 2, which has a multi-layer structure.

4. An adhesive film for metal terminals as described in claim 1 or 2, wherein the adhesive film for metal terminals is composed of a laminate having, in this order, a first resin layer arranged on the metal terminal side, an intermediate layer, and a second resin layer arranged on the exterior material side for the storage battery device.

5. An adhesive film for metal terminals as described in claim 4, wherein the second resin layer arranged on the side of the exterior material for the storage battery device is resin layer A.

6. An adhesive film for metal terminals according to claim 1 or 2, wherein the 25 volume % melting temperature of the resin layer A is 102°C or lower.

7. An adhesive film for metal terminals according to claim 1 or 2, having a thickness of 100 μm or more.

8. A method for producing an adhesive film for metal terminal, which is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element, wherein the exterior material for an electricity storage device has a heat-sealable resin layer arranged on the outermost surface on the electricity storage device element side, and a resin layer A constituting one surface of the adhesive film for metal terminal and the metal terminal are heat-sealed under conditions of a temperature of 200°C, a pressure of 0.25 MPa, and a time of 16 seconds to obtain a metal terminal with an adhesive film for metal terminal arranged so that the resin layer A is located on the surface, and the absolute value |P-Q| of the difference between the orientation degree P measured for the resin layer A of the metal terminal with the adhesive film for metal terminal and the orientation degree Q of the heat-sealable resin layer having an orientation degree of 0.000 to 0.100 is 0.200 or less.

9. A metal terminal with an adhesive film for a metal terminal, comprising an adhesive film for a metal terminal attached to a metal terminal, wherein the metal terminal is used so as to be electrically connected to an electrode of an electricity storage device element, the adhesive film for a metal terminal is used so as to be interposed between the metal terminal and an exterior material for an electricity storage device that encapsulates the electricity storage device element, and the exterior material for an electricity storage device has a heat-sealable resin layer disposed on the outermost surface on the electricity storage device element side, and the absolute value |P-Q| of the difference between the degree of orientation P measured for resin layer A constituting the surface of the adhesive film for a metal terminal of the metal terminal with an adhesive film for a metal terminal and the degree of orientation Q of a heat-sealable resin layer having an orientation degree of 0.000 to 0.100 is 0.200 or less.

10. An electricity storage device comprising: an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an exterior material for an electricity storage device that encapsulates the electricity storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding to the outside of the exterior material for an electricity storage device, wherein the exterior material for an electricity storage device is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order, the heat-sealable resin layer has a degree of orientation Q; and an adhesive film for a metal terminal is interposed between the metal terminal and the heat-sealable resin layer of the exterior material for an electricity storage device, and the absolute value |P-Q| of the difference between the degree of orientation P measured for resin layer A constituting one surface of the adhesive film for a metal terminal and the degree of orientation Q of the heat-sealable resin layer is 0.200 or less.

11. An exterior material for an electricity storage device for use in an electricity storage device, wherein the electricity storage device comprises at least an electricity storage device element having a positive electrode, a negative electrode, and an electrolyte, the exterior material for an electricity storage device sealing the electricity storage device element, and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding to the outside of the exterior material for an electricity storage device, and an adhesive film for metal terminal is interposed between the metal terminal and the exterior material for an electricity storage device, the adhesive film for metal terminal being the adhesive film for metal terminal according to claim 1 or 2, and the exterior material for an electricity storage device is composed of a laminate having at least a base layer, a barrier layer, and a heat-sealable resin layer in this order.

12. A kit comprising an exterior material for an electricity storage device for use in an electricity storage device and the adhesive film for metal terminals according to claim 1 or 2, wherein the electricity storage device comprises at least an electricity storage device element having a positive electrode, a negative electrode, and an electrolyte, the exterior material for an electricity storage device sealing the electricity storage device element, and the metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding outside the exterior material for an electricity storage device, the kit being used such that, during use, the adhesive film for metal terminals is interposed between the metal terminals and the exterior material for an electricity storage device.

13. A kit comprising an exterior material for an electricity storage device for use in an electricity storage device and a metal terminal with an adhesive film for a metal terminal as described in claim 9, wherein the electricity storage device comprises at least an electricity storage device element having a positive electrode, a negative electrode, and an electrolyte, the exterior material for an electricity storage device sealing the electricity storage device element, and a metal terminal with an adhesive film for a metal terminal electrically connected to each of the positive electrode and the negative electrode and protruding to the outside of the exterior material for an electricity storage device, the exterior material for an electricity storage device being composed of a laminate comprising at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order, and the kit is used such that, when in use, the metal terminal with an adhesive film for a metal terminal is interposed between the heat-sealable resin layers of the exterior material for an electricity storage device.

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