Adhesive film for metal terminal and method for producing same, metal terminal equipped with adhesive film for metal terminal, exterior material for electric storage device, kit comprising exterior material for electric storage device and adhesive film for metal terminal, and electric storage device and

Abstract

Disclosed is an adhesive film for a metal terminal, which is interposed between a metal terminal that is 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 for the metal terminal is configured from a laminate comprising at least a first layer disposed on the exterior material side for the electricity storage device, a colored layer, and a second layer disposed on the metal terminal side in this order, and the colored layer has a thickness of 50 [mu] m or less.

Description

Technical Field

[0001] The present invention relates to an adhesive film for metal terminals, a method for manufacturing the same, a metal terminal with an adhesive film for metal terminals, an outer packaging material for electrical storage devices, a kit including the outer packaging material for electrical storage devices and the adhesive film for metal terminals, and an electrical storage device and a method for manufacturing the same. Background Art

[0002] At present, various types of electrical storage devices have been developed. In all electrical storage devices, an outer packaging material for electrical storage devices has become an indispensable component for encapsulating electrical storage device elements such as electrodes and electrolytes. Conventionally, as the outer packaging material for electrical storage devices, a metal outer packaging material for electrical storage devices has been mostly used. However, in recent years, with the high-performance of electric vehicles, hybrid electric vehicles, computers, cameras, mobile phones, etc., various shapes have been required for electrical storage devices, and at the same time, thinning and lightening have also been required. However, in the case of the currently mostly used metal outer packaging material for electrical storage devices, there are disadvantages that it is difficult to follow the diversification of shapes, and there are also limitations in terms of lightening.

[0003] Therefore, in recent years, as an outer packaging material for electrical storage devices that can be easily processed into various shapes and can achieve thinning and lightening, a laminated sheet in which a base material layer / an adhesive layer / a barrier layer / a heat-sealable resin layer are laminated in sequence has been proposed. In the case of using such a laminated film-like outer packaging material for electrical storage devices, by heat-sealing the peripheral portion of the outer packaging material for electrical storage devices in a state where the heat-sealable resin layers located in the innermost layer of the outer packaging material for electrical storage devices face each other, the electrical storage device elements are encapsulated with the outer packaging material for electrical storage devices.

[0004] The metal terminal protrudes from the heat-sealed portion of the outer packaging material for electrical storage devices, and the electrical storage device elements encapsulated by the outer packaging material for electrical storage devices are electrically connected to the outside through the metal terminal electrically connected to the electrodes of the electrical storage device elements. That is, in the heat-sealed portion of the outer packaging material for electrical storage devices, the portion where the metal terminal is located is heat-sealed in a state where the metal terminal is sandwiched by the heat-sealable resin layer. Since the metal terminal and the heat-sealable resin layer are made of materials with different types, the adhesion at the interface between the metal terminal and the heat-sealable resin layer is likely to decrease.

[0005] Therefore, an adhesive film is sometimes disposed between the metal terminal and the heat-sealable resin layer for the purpose of improving their adhesion and the like. As such an adhesive film, for example, the film described in Patent Document 1 can be cited.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-79638 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] In recent years, with the increase in the capacity of electrical storage devices, the thickness of the adhesive film disposed between the metal terminal and the exterior material for the electrical storage device has a tendency to increase. As the thickness of the adhesive film increases, when heat-sealing the metal terminal and the exterior material for the electrical storage device via the adhesive film, there is a tendency to use higher temperature, higher pressure, and longer sealing conditions.

[0011] In addition, in order to dispose the adhesive film at a high positional accuracy between the metal terminal and the exterior material for the electrical storage device, a colored layer is sometimes provided on the adhesive film.

[0012] The inventors of the present invention conducted research and found that if a large amount of heat is applied during the sealing of the adhesive film, the colored layer of the adhesive film sometimes flows out, making it difficult to dispose the adhesive film at a high positional accuracy by means of a sensor or the like.

[0013] The main object of the present invention is to provide an adhesive film for a metal terminal, which is an adhesive film for a metal terminal that exists between a metal terminal electrically connected to an electrode of an electrical storage device element and an exterior material for an electrical storage device that encapsulates the electrical storage device element and has a colored layer, and can suppress the outflow of the colored layer caused by heating during sealing. In addition, the object of the present invention is also to provide a method for manufacturing the adhesive film for a metal terminal, a metal terminal with the adhesive film for a metal terminal, an exterior material for an electrical storage device, a kit including the exterior material for an electrical storage device and the adhesive film for a metal terminal, an electrical storage device, and a method for manufacturing the electrical storage device.

[0014] Technical Solution for Solving the Problem

[0015] The inventors of the present invention and the like conducted in-depth research to solve the above technical problems. As a result, it was found that the following adhesive film for a metal terminal can suppress the outflow of the colored layer caused by heating during sealing. The adhesive film for a metal terminal exists between a metal terminal electrically connected to an electrode of an electrical storage device element and an exterior material for an electrical storage device that encapsulates the electrical storage device element, and is composed of a laminate including at least a first layer disposed on the side of the exterior material for the electrical storage device, a colored layer, and a second layer disposed on the side of the metal terminal in this order, and the thickness of the colored layer is 50 μm or less. The present invention was completed by further repeated research based on this finding.

[0016] That is, the present invention provides an invention in the following manner.

[0017] An adhesive film for a metal terminal, which exists between a metal terminal electrically connected to an electrode of an electrical storage device element and an exterior material for an electrical storage device that encapsulates the electrical storage device element,

[0018] The adhesive film for metal terminals is composed of a laminate including at least a first layer disposed on the side of the exterior material for the electrical storage device, a coloring layer, and a second layer disposed on the side of the metal terminals in this order.

[0019] The thickness of the coloring layer is 50 μm or less.

[0020] Advantages of the Invention

[0021] According to the present invention, there is provided an adhesive film for metal terminals which is disposed between a metal terminal electrically connected to an electrode of an electrical storage device element and an exterior material for the electrical storage device encapsulating the electrical storage device element, and which has a coloring layer. The adhesive film for metal terminals can suppress the outflow of the coloring layer caused by heating during sealing. By suppressing the outflow of the coloring layer caused by heating during sealing of the adhesive film for metal terminals, for example, the adhesive film for metal terminals can be disposed with high positional accuracy between the metal terminal and the exterior material for the electrical storage device. In addition, the present invention also aims to provide a method for manufacturing the adhesive film for metal terminals, a metal terminal with the adhesive film for metal terminals, an exterior material for the electrical storage device, a kit including the exterior material for the electrical storage device and the adhesive film for metal terminals, and an electrical storage device and a method for manufacturing the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a plan view of a schematic diagram of an electrical storage device of the present invention.

[0023] Figure 2 is Figure 1 a cross-sectional view of a schematic diagram of line A - A' of

[0024] Figure 3 is Figure 1 a cross-sectional view of a schematic diagram of line B - B' of

[0025] Figure 4 is a cross-sectional view of a schematic diagram of the adhesive film for metal terminals of the present invention.

[0026] Figure 5 is a cross-sectional view of a schematic diagram of the adhesive film for metal terminals of the present invention.

[0027] Figure 6 is a cross-sectional view of a schematic diagram of the adhesive film for metal terminals of the present invention.

[0028] Figure 7 is a cross-sectional view of a schematic diagram of the adhesive film for metal terminals of the present invention.

[0029] Figure 8 is a cross-sectional view of a schematic diagram of the exterior material for the electrical storage device of the present invention.

[0030] Figure 9It is a schematic diagram for explaining a method for measuring the water vapor transmission rate of the adhesive film for metal terminals of the present invention.

[0031] Figure 10 It is a schematic diagram (plan view) for explaining a method for measuring the flow amount of the colored layer after sealing.

[0032] Figure 11 It is a schematic diagram (cross-sectional view) for explaining a method for measuring the flow amount of the colored layer after sealing. Detailed Description of the Invention

[0033] The adhesive film for metal terminals of the present invention is an adhesive film for metal terminals existing between a metal terminal electrically connected to an electrode of an electric storage device element and an outer package material for an electric storage device that encapsulates the electric storage device element. The adhesive film for metal terminals is characterized in that it is composed of a laminate including at least a first layer disposed on the side of the outer package material for an electric storage device, a colored layer, and a second layer disposed on the side of the metal terminal in this order, and the thickness of the colored layer is 50 μm or less.

[0034] Since the adhesive film for metal terminals of the present invention has such a feature, it is possible to suppress the outflow of the colored layer caused by heating during sealing. By suppressing the outflow of the colored layer caused by heating during sealing of the adhesive film for metal terminals, for example, the adhesive film for metal terminals can be disposed with high positional accuracy between the metal terminal and the outer package material for an electric storage device.

[0035] In addition, the electric storage device of the present invention is characterized in that it includes: an electric storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an outer package material for an electric storage device that encapsulates the electric storage device element; and metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the outer package material for an electric storage device, and the adhesive film for metal terminals of the present invention exists between the metal terminals and the outer package material for an electric storage device.

[0036] Hereinafter, the adhesive film for metal terminals of the present invention, its manufacturing method, the electric storage device, and its manufacturing method will be described in detail.

[0037] In addition, in this specification, regarding the numerical range, the numerical range indicated by "~" means "above" and "below". For example, the expression of 2~15 mm means 2 mm or more and 15 mm or less. In the numerical ranges described stepwise in the present invention, the upper limit value or the lower limit value described in a certain numerical range can be replaced with the upper limit value or the lower limit value of other stepwise described numerical ranges. In addition, the upper limit values described separately can be combined with each other, the upper limit value and the lower limit value, or the lower limit values and the lower limit values respectively as numerical ranges. In addition, in the numerical ranges described in the present invention, the upper limit value or the lower limit value described in a certain numerical range can be replaced with the value shown in the examples.

[0038] In addition, as a method for confirming the MD of the adhesive film for metal terminals, there is a method for confirming the sea island structure by observing the cross section of the adhesive film for metal terminals through an electron microscope. In this method, the direction parallel to the cross section with the largest average diameter of the shape of the island in the direction perpendicular to the thickness direction of the adhesive film for metal terminals can be judged as MD. Specifically, for the cross section in the length direction of the adhesive film for metal terminals, and each cross section (a total of 10 cross sections) in which the angle is changed by 10 degrees each time from the direction parallel to the cross section in the length direction to the direction perpendicular to the cross section in the length direction, the sea island structure is confirmed by electron microscope observation. Then, in each cross section, the shape of each island is observed separately. Regarding the shape of each island, the straight line distance connecting the leftmost end of the direction perpendicular to the thickness direction of the adhesive film for metal terminals and the rightmost end of the perpendicular direction is set as the diameter y. Calculate the average of the first 20 diameters y of the diameter y of the shape of the island in each cross section from large to small. The direction parallel to the cross section with the largest average diameter y of the shape of the island is judged as MD. Alternatively, for example, the adhesive film for a metal terminal may be left in an environment at 150° C. for 2 minutes and then the heat shrinkage rate may be measured, and the larger shrinkage rate may be determined as the MD.

[0039] 1. Adhesive Film for Metal Terminals

[0040] The adhesive film for metal terminals of the present invention is present between a metal terminal electrically connected to an electrode of an electric storage device element and an outer packaging material for an electric storage device that seals the electric storage device element. Figures 1 to 3 As shown, the adhesive film 1 for metal terminals of the present invention is present between the metal terminal 2 electrically connected to the electrode of the storage device element 4 and the storage device outer packaging material 3 that encapsulates the storage device element 4. In addition, the metal terminal 2 protrudes to the outside of the storage device outer packaging material 3, and is sandwiched by the storage device outer packaging material 3 via the adhesive film 1 for metal terminals in the peripheral portion 3a of the storage device outer packaging material 3 that is heat-sealed.

[0041] In addition, in the present invention, the preliminary bonding process of the adhesive film for metal terminal to the metal terminal is carried out under the conditions of, for example, 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 times, and the main bonding process is carried out under the conditions of, for example, 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 times. In addition, the heating temperature when heat-sealing the metal terminal with the adhesive film for metal terminal through the outer packaging material for the storage device is usually in the range of about 180 to 210° C., and the pressure is usually about 1.0 to 5.0 MPa, and the time is about 1 to 5 seconds and the number of times is about 1.

[0042] The adhesive film 1 for metal terminals of the present invention (hereinafter, sometimes simply referred to as "adhesive film") is provided to improve the adhesion between the metal terminal 2 and the exterior material 3 for electrical storage devices. By improving the adhesion between the metal terminal 2 and the exterior material 3 for electrical storage devices, the sealing performance of the electrical storage device element 4 is improved. As described above, when heat-sealing the electrical storage device element 4, the metal terminal 2 electrically connected to the electrode of the electrical storage device element 4 protrudes outside the exterior material 3 for electrical storage devices to encapsulate the electrical storage device element. At this time, the metal terminal 2 formed of metal and the heat-sealing resin layer 35 (a layer formed of a heat-sealing resin such as polyolefin) located in the innermost layer of the exterior material 3 for electrical storage devices are made of different materials. Therefore, in the case of not using such an adhesive film, the sealing performance of the electrical storage device element is likely to be reduced at the interface between the metal terminal 2 and the heat-sealing resin layer 35.

[0043] [Coloring layer 11]

[0044] The adhesive film 1 for metal terminals of the present invention has at least a first layer, a coloring layer, and a second layer arranged in this order on the side of the exterior material for electrical storage devices. The thickness of the coloring layer is 50 μm or less.

[0045] More specifically, as Figures 4 to 7 shown, the adhesive film 1 for metal terminals of the present invention includes at least 1 coloring layer 11 between the first layer 12a and the second layer 12b. That is, the coloring layer 11 is not a layer constituting the surface of the adhesive film 1 for metal terminals. The adhesive film 1 for metal terminals preferably has a 3 - 6 layer structure. Figure 4 shows the laminated structure of the adhesive film 1 for metal terminals having a 3 - layer structure in which the first layer 12a on the side of the exterior material 3 for electrical storage devices, the coloring layer 11, and the second layer 12b on the side of the metal terminal 2 are laminated in this order. In addition, Figure 6 shows the laminated structure of the adhesive film 1 for metal terminals having a 5 - layer structure in which the first layer 12a on the side of the exterior material 3 for electrical storage devices, the third layer 12c, the coloring layer 11, the fourth layer 12d, and the second layer 12b on the side of the metal terminal 2 are laminated in this order. Figure 7 shows the laminated structure of the adhesive film 1 for metal terminals having a 4 - layer structure in which the first layer 12a on the side of the exterior material 3 for electrical storage devices, the coloring layer 11, the base material 14, and the second layer 12b on the side of the metal terminal 2 are laminated in this order. In Figure 4 and Figure 5 shown for the adhesive film 1 for metal terminals, the manner in which the coloring layer 11 constitutes the base material 14 is shown. In addition, Figure 7 shows the manner in which the base material 14 is laminated in addition to the coloring layer 11. In addition, Figure 5In this case, as described later, a laminated structure is shown in which an adhesion promoter layer 13 is provided for the purpose of firmly bonding the coloring layer 11 to the first layer 12a and the coloring layer 11 to the second layer 12b.

[0046] From the viewpoint of more suitably exhibiting the effects of the present invention, the ratio of the thickness of the coloring layer 11 of the adhesive film 1 for metal terminals to the thickness of the adhesive film for metal terminals is preferably about 0.30 or less, more preferably about 0.25 or less, and further preferably about 0.20 or less. In addition, it is preferably about 0.01 or more, more preferably about 0.03 or more, and further preferably about 0.05 or more. In addition, as a preferable range, about 0.01 to 0.30, about 0.01 to 0.25, about 0.01 to 0.20, about 0.03 to 0.30, about 0.03 to 0.25, about 0.03 to 0.20, about 0.05 to 0.30, about 0.05 to 0.25, and about 0.05 to 0.20 can be cited.

[0047] The coloring layer 11 is preferably a layer formed of a polyolefin resin containing a colorant. As the polyolefin resin, polyolefins, acid-modified polyolefins, etc. can be cited. As polyolefins, specifically, polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, etc.; crystalline or amorphous polypropylene such as homopolypropylene, block copolymers of polypropylene (for example, block copolymers of propylene and ethylene), random copolymers of polypropylene (for example, random copolymers of propylene and ethylene), etc.; ethylene-butene-propylene terpolymers, etc. Among these polyolefins, polyethylene and polypropylene are preferably cited, and polypropylene is more preferably cited. The coloring layer 11 is preferably a layer formed of polypropylene containing a colorant. Among polypropylenes, homopolypropylene and block copolymers of polypropylene are preferred.

[0048] In addition, the polyolefin of the coloring layer 11 may contain a modified olefin or may be a modified olefin. As the acid-modified polyolefin, acid-modified polyolefins can be cited. As the acid-modified polypropylene, as long as it is a polyolefin after acid modification, there is no particular limitation, and polyolefins graft-modified with an unsaturated carboxylic acid or its acid anhydride are preferably cited. As the polyolefins that can be acid-modified, specifically, polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, etc.; crystalline or amorphous polypropylene such as homopolypropylene, block copolymers of polypropylene (for example, block copolymers of propylene and ethylene), random copolymers of polypropylene (for example, random copolymers of propylene and ethylene), etc.; ethylene-butene-propylene terpolymers, etc. Among these polyolefins, polyethylene and polypropylene are preferably cited, and polypropylene is more preferably cited.

[0049] The colored layer 11 can be formed of a single resin component or a blended polymer formed of two or more resin components combined.

[0050] Examples of the carboxylic acid or its anhydride used for acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride, etc. In the case of a resin layer containing maleic anhydride, when analyzed by infrared spectroscopy, a peak derived from maleic anhydride can preferably be detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride can be detected around a wave number of 1760 cm -1 and around a wave number of 1780 cm -1 . In the case where the colored layer 11 is a layer composed of maleic anhydride-modified polyolefin, when measured by infrared spectroscopy, a peak derived from maleic anhydride can be detected. However, if the degree of acid modification is low, the peak is small and sometimes cannot be detected. In such a case, nuclear magnetic resonance spectroscopy can be used for analysis.

[0051] The colored layer 11 is the layer to be colored. The colored layer 11 can be colored, for example, by containing a colorant. The colorant is not particularly limited, and a colorant capable of coloring the resin layer can be suitably used. The colored layer 11 is preferably black.

[0052] The colorant is not particularly limited, and a colorant capable of coloring the resin layer can be suitably used. Specific examples of the colorant include pigments. As the pigments, various inorganic or organic pigments can be used. Specific examples of the pigments include, in addition to carbon (charcoal, graphite), silica, titanium oxide, iron oxide, zinc oxide, magnesium oxide, and calcium oxide exemplified in the above fillers, inorganic oxides such as titanium nitride, zirconium black oxide, copper oxide, cobalt oxide, and barium sulfate. Additionally, organic pigments such as quinacridone-based pigments, polyazo-based pigments, and isoindolinone-based pigments can be preferably exemplified. Carbon (charcoal, graphite) is usually a material used inside the electrical storage device, and there is no concern about elution into the electrolyte. In addition, a sufficient coloring effect can be obtained with an addition amount that provides a large coloring effect without impairing the adhesiveness, and it does not melt due to heat, and can increase the apparent melt viscosity of the added resin. Furthermore, it can prevent the pressure portion from thinning during thermal bonding (heat sealing), and can impart excellent sealing performance between the exterior material for the electrical storage device and the metal terminal.

[0053] The color of the colored layer 11 is not particularly limited and can be selected according to the purpose. The colored layer 11 is preferably black, gray, or white, for example.

[0054] When adding a pigment to the coloring layer 11, as the addition amount, for example, when using carbon black with a particle size of about 0.03 μm, with respect to 100 parts by mass of the resin component forming the coloring layer 11, about 0.05 to 0.3 parts by mass, preferably about 0.1 to 0.2 parts by mass can be cited respectively. By adding a pigment to the coloring layer 11, the presence or absence of the adhesive film 1 for metal terminals can be detected by a sensor, or inspection can be performed by visual observation. In addition, when adding the filler and pigment described below to the coloring layer 11, the filler and pigment can be added in the same coloring layer 11, but from the viewpoint of not hindering the heat melt adhesiveness of the adhesive film 1 for metal terminals, it is preferable to add the filler and pigment to different layers (for example, the coloring layer 11, and the first layer 12a, second layer 12b, third layer 12c, fourth layer 12d, base material 14, etc. described below).

[0055] When adding a pigment to the coloring layer 11, as the addition amount, for example, when using carbon black with a particle size of about 0.03 μm, with respect to 100 parts by mass of the resin component forming the coloring layer 11, about 0.05 to 0.3 parts by mass, preferably about 0.1 to 0.2 parts by mass can be cited respectively. By adding a pigment to the coloring layer 11, the presence or absence of the adhesive film 1 for metal terminals can be detected by a sensor, or inspection can be performed by visual observation. In addition, when adding the filler and pigment described below to the coloring layer 11, the filler and pigment can be added in the same coloring layer 11, but from the viewpoint of not hindering the heat melt adhesiveness of the adhesive film 1 for metal terminals, it is preferable to add the filler and pigment to different layers (for example, the coloring layer 11, and the first layer 12a, second layer 12b, third layer 12c, fourth layer 12d, base material 14, etc. described below).

[0056] In addition, in the adhesive film 1 for metal terminals of the present invention, the thickness of the coloring layer 11 may be 50 μm or less, but from the viewpoint of more suitably exerting the effects of the present invention, the thickness of the coloring layer 11 is preferably about 45 μm or less, more preferably about 40 μm or less, further preferably about 35 μm or less, still further preferably about 30 μm or less. In addition, it is preferably about 3 μm or more, more preferably about 5 μm or more, further preferably about 10 μm or more. As a preferable range, about 3 to 50 μm, about 3 to 45 μm, about 3 to 40 μm, about 3 to 35 μm, about 3 to 30 μm, about 5 to 50 μm, about 5 to 45 μm, about 5 to 40 μm, about 5 to 35 μm, about 5 to 30 μm, about 10 to 50 μm, about 10 to 45 μm, about 10 to 40 μm, about 10 to 35 μm, about 10 to 30 μm can be cited.

[0057] Further, from the viewpoint of more suitably exerting the effects of the present invention, the softening point of the coloring layer 11 is preferably higher than that of the second layer 12b described later. The softening point of the coloring layer 11 is preferably about 95°C or higher, more preferably about 100°C or higher, still more preferably about 105°C or higher. Further, it is preferably about 140°C or lower, more preferably about 130°C or lower, still more preferably about 120°C or lower. As preferred ranges, about 95 to 140°C, about 95 to 130°C, about 95 to 120°C, about 100 to 140°C, about 100 to 130°C, about 100 to 120°C, about 105 to 140°C, about 105 to 130°C, about 105 to 120°C can be cited. In the present invention, the method for measuring the softening point is as described below.

[0058] <Measurement of Softening Point>

[0059] A commercially available softening point measuring device is used. Calibration is performed through the following process before measurement. Standard specimens are polycaprolactone (softening point: 55°C), polyethylene (softening point: 116°C), and polyethylene terephthalate (softening point: 235°C) with known softening points. While heating with the surface of each standard specimen in contact with the thermal probe. During heating, the thermal expansion directly below the thermal probe is measured to obtain a curve graph representing the Deflection (displacement) relative to Voltage (potential). The measurement conditions set in the device are as follows.

[0060] Measurement start temperature: 0.1V

[0061] Measurement end temperature: 10V

[0062] Temperature increase rate: 0.2V / sec

[0063] Using the softening points of the respective standard specimens, the curve graph representing the displacement of the thermal probe relative to the potential is converted into a curve graph representing the displacement relative to the temperature. After calibration, the thermal probe is brought into contact with the measurement site of the cross-section of the specimen formed with a diamond knife or the like after being embedded in the resin. Then, while the thermal probe is in contact, heating is performed under the following conditions to obtain a curve graph representing the displacement of the thermal probe relative to the temperature (thermal expansion curve).

[0064] Measurement start temperature: 40°C

[0065] Measurement end temperature: 350°C

[0066] Temperature increase rate: 5°C / sec

[0067] In the obtained thermal expansion curve, the temperature at which the curve reaches its peak is obtained. The above measurement is performed at five arbitrary locations. The average value of the obtained temperatures is taken as the softening point.

[0068] In addition, from the viewpoint of more suitably exerting the effects of the present invention, the melting peak temperature of the coloring layer 11 is preferably about 135°C or higher, more preferably about 145°C or higher, and further preferably about 155°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, and further preferably about 165°C or lower. As the preferred range of the melting peak temperature, there may be mentioned about 135 to 180°C, about 135 to 175°C, about 135 to 170°C, about 135 to 165°C, about 145 to 180°C, about 145 to 175°C, about 145 to 170°C, about 145 to 165°C, about 155 to 180°C, about 155 to 175°C, about 155 to 170°C, and about 155 to 165°C. In the present invention, the method for measuring the melting peak temperature is as described below.

[0069] <Measurement of Melting Peak Temperature>

[0070] Regarding the adhesive film, the melting peak temperature is measured in accordance with the provisions of JIS K7121:2012 (Test Method for Vicat Softening Temperature of Plastics (Addendum 1 to JIS K7121:1987)). The measurement is carried out using a differential scanning calorimeter. After holding the measurement sample at -50°C for 15 minutes, it is heated from -50°C to 210°C at a heating rate of 10°C / minute, and the first melting peak temperature P (°C) is measured. Then, it is held at 210°C for 10 minutes. Next, it is cooled from 210°C to -50°C at a cooling rate of 10°C / minute and held at -50°C for 15 minutes. Further, it is heated from -50°C to 210°C at a heating rate of 10°C / minute to measure the second melting peak temperature Q (°C). In addition, the flow rate of nitrogen is set to 50 ml / minute. Through the above steps, the first measured melting peak temperature P (°C) and the second measured melting peak temperature Q (°C) are obtained. The value of the first measured melting peak temperature P (°C) obtained through the above steps is adopted.

[0071] From the viewpoint of more suitably exerting the effects of the present invention, the island portion ratio of the sea-island structure of the coloring layer 11 is preferably about 30% or less, more preferably about 25% or less, and further preferably about 20% or less. In addition, it is preferably about 0% or more, more preferably about 5% or more, and further preferably about 10% or more. As the preferred range, 0 to about 30%, 0 to about 25%, 0 to about 20%, 5 to about 30%, 5 to about 25%, 5 to about 20%, 10 to about 30%, 10 to about 25%, and 10 to about 20% can be cited. The island portion ratio of the sea-island structure of the coloring layer 11 can be adjusted, for example, by controlling the content rate of polyethylene in the polypropylene film, the polymerization form (homopolymerization, block, or random), and the film-forming conditions (temperature and speed during film formation, cooling temperature and speed, etc.). The island portion ratio of the sea-island structure of the coloring layer 11 is a value measured by the following method.

[0072] <Measurement of the island portion ratio of the sea-island structure of the coloring layer 11>

[0073] Embed the adhesive film in a thermosetting epoxy resin and cure it. Use a commercially available rotary microtome and a diamond knife to produce a cross-section in the target direction (a cross-section parallel to the TD and in the thickness direction). At this time, use a cryo-ultramicrotome with liquid nitrogen to produce the cross-section at -70°C. After staining each embedding resin with ruthenium tetroxide for 12 hours, trim the swollen part with a microtome, and cut in the MD direction in increments of 300 nm starting from 100 nm. When cutting a total of about 1 μm to 2 μm, observe the cross-section where the coloring layer is exposed as follows. For the stained cross-section, observe it using a field emission scanning electron microscope (measurement conditions: 3 kV 20 mA High WD6 mm detector (Upper)) to obtain an image (magnification: 10,000 times). Then, use image processing software capable of binarizing the image to binarize the island part and the sea part of the sea-island structure in this image, and calculate the ratio of the total area of the island part (total area of the island part / area of the measurement range of the image).

[0074] [Image processing conditions]

[0075] The image processing is performed using the image analysis software ImageJ. Specifically, obtain the SEM image in the form of a digital file of a grayscale image (JPEG), and process it according to the following binarization processing procedure and parameters. Output the pixels with a tone (bright) above the threshold as 1, and output the pixels with a tone (dark) less than the threshold as 0, and respectively define them as the island part and the sea part.

[0076] <Binarization processing>

[0077] 1. Spiking noise removal (Despeckle)

[0078] 2. Removal of the outline of the island part (Remove Outliers radius=4 threshold=1 which=Bright)

[0079] 3. Removal of the outline of the sea part (Remove Outliers radius=4 threshold=1 which=Dark)

[0080] 4. Removal of spike noise (Despeckle)

[0081] 5. Gaussian blur in the X-axis (short side of the sample) direction (threshold=3 pixels)

[0082] 6. Contrast enhancement (saturated=0.2)

[0083] 7. Removal of the outline of the island part (Remove Outliers radius=4 threshold=1 which=Bright)

[0084] 8. Removal of the outline of the sea part (Remove Outliers radius=4 threshold=1 which=Dark)

[0085] 9. Otsu binarization

[0086] From the viewpoint of more suitably exerting the effects of the present invention, regarding the coloring layer 11, after heating the adhesive film 1 for metal terminals under the conditions of a temperature of 200°C, a surface pressure of 0.25 MPa, and 16 seconds, in an environment of a temperature of 40°C, the ratio of the soft segment component measured by the solid echo method of pulsed NMR is preferably about 35% or less, more preferably about 30% or less, still more preferably about 25% or less. In addition, it is preferably about 4% or more, preferably about 5% or more, more preferably about 10% or more, still more preferably about 15% or more. As the preferred range, 4 to about 35%, 4 to about 30%, 4 to about 25%, 5 to about 35%, 5 to about 30%, 5 to about 25%, 10 to about 35%, 10 to about 30%, 10 to about 25%, 15 to about 35%, 15 to about 30%, 15 to about 25% can be cited. The ratio of the soft segment component of the adhesive film 1 after heating can be adjusted, for example, by controlling the content ratio of polyethylene in the polypropylene film, the polymerization form (homopolymerization, block, or random), and the film-forming conditions (temperature and speed during film formation, cooling temperature and speed, etc.). The measurement method of the ratio of the soft segment component of the adhesive film 1 after heating is as described below.

[0087] <Measurement of the ratio of the soft segment component of the adhesive film after heating>

[0088] The adhesive film is heated under the conditions of a temperature of 200 °C, a surface pressure of 0.25 MPa, and 16 seconds. This heat treatment assumes the physical properties after the adhesive film is disposed between the exterior material for the electrical storage device and the metal terminal and heat-sealed. The adhesive film for the metal terminal 1 is introduced into a glass sample tube with a diameter of 10 mm, the sample tube is set in a pulsed NMR device, and after maintaining at 40 °C for 5 minutes, a free induction decay curve of the spin-spin relaxation of 1H is obtained at 40 °C by the solid echo method. The number of scans in the solid echo method is set to 64 times. The obtained decay curve waveform is separated into three curves of three components derived from the hard segment component, the middle segment component, and the soft segment component. The waveform separation uses the analysis software "TD-NMRA (Version 4.3Rev 0.8)" manufactured by BRUKER Corporation. The hard segment component is obtained by fitting with a Gaussian type as a function, and the middle segment component and the soft segment component are obtained by fitting with an exponential type as a function. The measurement points up to 0.6 msec of the relaxation curve are used in the analysis. The fitting uses the following formula.

[0089] Y = A1 × exp(−(t / τ1) w1 ) + A2 × exp(−(t / τ2) w2 ) + A3 × exp(−(t / τ3) w3 )

[0090] Among them, w1 to w3 are Weber coefficients, w1 takes a value of 2, and w2 and w3 take a value of 1. A1 is the component ratio of the hard segment component, A2 is the component ratio of the middle segment component, A3 is the component ratio of the soft segment component, τ1 represents the relaxation time of the hard segment component, τ2 represents the relaxation time of the middle segment component, τ3 represents the relaxation time of the soft segment component, and t is the time. The component ratios A1, A2, and A3 are the average values obtained by performing the same-level measurement three times.

[0091] In the coloring layer 11, known additives can be included as needed.

[0092] For example, in the coloring layer 11, a filler can be included as needed. By including a filler in the coloring layer 11, since the filler functions as a spacer, a short circuit between the metal terminal 2 and the barrier layer 33 of the exterior material 3 for the electrical storage device can be effectively suppressed. As the particle diameter of the filler, a range of about 0.1 to 35 μm, preferably about 5.0 to 30 μm, and more preferably about 10 to 25 μm can be cited. In addition, as the content of the filler, with respect to 100 parts by mass of the resin component forming the coloring layer 11, about 5 to 30 parts by mass, more preferably about 10 to 20 parts by mass can be cited respectively.

[0093] As the filler, any inorganic or organic filler can be used. As the inorganic filler, for example, carbon (charcoal, graphite), silica, alumina, barium titanate, iron oxide, silicon carbide, zirconia, zirconium silicate, magnesia, titanium oxide, calcium aluminate, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, calcium carbonate, etc. can be cited. In addition, as the organic filler, for example, fluororesin, phenolic resin, urea resin, epoxy resin, acrylic resin, benzoguanamine-formaldehyde condensate, melamine-formaldehyde condensate, polymethyl methacrylate cross-linked product, polyethylene cross-linked product, etc. can be cited. From the viewpoints of shape stability, rigidity, and content resistance, alumina, silica, fluororesin, acrylic resin, and benzoguanamine-formaldehyde condensate are preferred, and among them, spherical alumina and silica are more preferred. As the mixing method of the filler mixed with the resin component for forming the colored layer 11, a method of melt-blending the two in advance with a Banbury mixer or the like and making the granulated product into a specified mixing ratio, a method of directly mixing with the resin component, etc. can be adopted.

[0094] As described above, the adhesive film 1 for metal terminals of the present invention, for example, as Figures 4 to 7 shown, can be set to a structure in which at least the first layer 12a, the colored layer 11, and the second layer 12b are laminated in this order. In this structure, the first layer 12a is disposed on the side of the exterior material 3 for the electrical storage device, and the second layer 12b is disposed on the side of the metal terminal 2. The colored layer 11 is disposed between the first layer 12a and the second layer 12b and can constitute the base material 14 or the intermediate layer. In Figures 4 to 7 the laminated structure, the first layer 12a and the second layer 12b are respectively located on the surfaces on both sides. In addition, in Figure 6 the laminated structure, a third layer 12c is provided between the first layer 12a and the colored layer 11, and a fourth layer 12d is provided between the colored layer 11 and the second layer 12b. The adhesive film 1 for metal terminals of the present invention is preferably composed of 3 to 6 layers, and at least has the first layer 12a constituting the surface on the side of the exterior material 3 for the electrical storage device, the second layer 12b constituting the surface on the side of the metal terminal 2, and the colored layer 11 located between the first layer 12a and the second layer 12b.

[0095] If the adhesive film 1 for a metal terminal of the present invention is disposed between the metal terminal 2 of the electrical storage device 10 and the exterior material 3 for the electrical storage device, 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 3 for the electrical storage device are adhered to each other with the adhesive film 1 for a metal terminal interposed therebetween. The first layer 12a of the adhesive film 1 for a metal terminal is disposed on the side of the exterior material 3 for the electrical storage device, and the second layer 12b is disposed on the side of the metal terminal 2. The first layer 12a is in close contact with the heat-sealable resin layer 35 of the exterior material 3 for the electrical storage device, and the second layer 12b is in close contact with the metal terminal 2. The first layer 12a may be a single layer or multiple layers. Further, the second layer 12b may be a single layer or multiple layers.

[0096] The first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. contained in the adhesive film 1 for a metal terminal may be formed of resin films, respectively. When the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. are laminated with the coloring layer 11, etc. to manufacture the adhesive film 1 for a metal terminal of the present invention in the case where the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. are formed of resin films, respectively, the previously formed resin films may be used as the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc., respectively. Further, the resins forming the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. may be made into films on the surface of the coloring layer 11, etc. by extrusion molding or coating, etc., as the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. formed of resin films.

[0097] The first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. contained in the adhesive film 1 for a metal terminal may be made of resin, respectively. Examples of the resin constituting the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. include polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicone resins, phenolic resins, polyetherimides, polyimides, polycarbonates, and mixtures or copolymers thereof, etc. Among these, polyolefin resins are particularly preferred. Examples of the polyolefin resins include polyolefins, acid-modified polyolefins, etc. Examples of the polyolefins include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, etc.; crystalline or amorphous polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene), etc.; and terpolymers of ethylene - butene - propylene. Among these polyolefins, polyethylene and polypropylene are preferably mentioned, and polypropylene is more preferably mentioned.

[0098] The first layer 12a disposed on the side of the exterior material 3 for the electrical storage device more preferably contains polyolefin as the main component, and further preferably contains polypropylene as the main component. Here, as the main component, it means that among the resin components contained in the first layer 12a, the content rate is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, further preferably 90% by mass or more, further preferably 95% by mass or more, further preferably 98% by mass or more, and further preferably 99% by mass or more of the resin component. For example, the first layer 12a containing polypropylene as the main component means that among the resin components contained in the first layer 12a, the content rate of polypropylene is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, further preferably 90% by mass or more, further preferably 95% by mass or more, further preferably 98% by mass or more, and further preferably 99% by mass or more.

[0099] In addition, the second layer 12b disposed on the side of the metal terminal 2 more preferably contains acid-modified polyolefin as the main component, and further preferably contains acid-modified polypropylene as the main component. Here, the main component means that among the resin components contained in the second layer 12b, the content rate is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, further preferably 90% by mass or more, further preferably 95% by mass or more, further preferably 98% by mass or more, and further preferably 99% by mass or more of the resin component. For example, the second layer 12b containing acid-modified polypropylene as the main component means that among the resin components contained in the second layer 12b, the content rate of acid-modified polypropylene is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, further preferably 90% by mass or more, further preferably 95% by mass or more, further preferably 98% by mass or more, and further preferably 99% by mass or more.

[0100] The melting peak temperatures of the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. are preferably 125°C or higher, more preferably about 130°C or higher, and further 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, further preferably about 165°C or lower, and further preferably about 160°C or lower. As the preferred range of the melting peak temperature, 125 to 180°C, 125 to 175°C, 125 to 170°C, 125 to 165°C, 125 to 160°C, 130 to 180°C, 130 to 175°C, 130 to 170°C, 130 to 165°C, 130 to 160°C, 135 to 180°C, 135 to 175°C, 135 to 170°C, 135 to 165°C, 135 to 160°C can be cited.

[0101] The softening points of the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. are preferably about 70°C or higher, more preferably about 75°C or higher, and further preferably about 80°C or higher. In addition, it is preferably about 130°C or lower, more preferably about 120°C or lower, and further preferably about 110°C or lower. As the preferred range, 70 to 130°C, 70 to 120°C, 70 to 110°C, 75 to 130°C, 75 to 120°C, 75 to 110°C, 80 to 130°C, 80 to 120°C, 80 to 110°C can be cited. In particular, the softening point of the second layer 12b is preferably lower than the softening point of the coloring layer 11, preferably about 70°C or higher, more preferably about 75°C or higher, and further preferably about 80°C or higher. In addition, it is preferably about 120°C or lower, more preferably about 110°C or lower, and further preferably about 100°C or lower. As the preferred range, 70 to 120°C, 70 to 110°C, 70 to 100°C, 75 to 120°C, 75 to 110°C, 75 to 100°C, 80 to 120°C, 80 to 110°C, 80 to 100°C can be cited.

[0102] In addition, the thicknesses of the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc. are preferably about 10 μm or more, more preferably about 15 μm or more, and further preferably about 20 μm or more. In addition, they are preferably about 120 μm or less, more preferably about 100 μm or less, and further preferably 80 μm or less. As the preferred range of the thickness of the resin layer B, examples 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.

[0103] In addition, in the first layer 12a, the second layer 12b, the third layer 12c, the fourth layer 12d, etc., known additives (such as the above-mentioned fillers, pigments, etc.) can be contained in the same manner as in the colored layer 11. Regarding the types or addition amounts of the fillers and pigments, it is the same as in the colored layer 11.

[0104] From the viewpoint of more suitably exerting the effects of the present invention, the total thickness of the adhesive film 1 for metal terminals is, for example, about 50 μm or more, preferably about 80 μm or more, more preferably about 90 μm or more, and further preferably about 100 μm or more. In addition, the total thickness of the adhesive film 1 for metal terminals of the present invention is about 500 μm or less, preferably about 300 μm or less, more preferably about 250 μm or less, and further preferably 200 μm or less. As the preferred range of the total thickness of the adhesive film 1 for metal terminals of the present invention, examples include about 50 to 500 μm, about 50 to 300 μm, about 50 to 250 μm, about 50 to 200 μm, about 80 to 500 μm, about 80 to 300 μm, about 80 to 250 μm, about 80 to 200 μm, about 90 to 500 μm, about 90 to 300 μm, about 90 to 250 μm, about 90 to 200 μm, about 100 to 500 μm, about 100 to 300 μm, about 100 to 250 μm, and about 100 to 200 μm. As a more specific example, for instance, when the adhesive film 1 for metal terminals of the present invention is used in relatively small-sized electrical storage devices for mobile phones, smartphones, and tablets, the total thickness is preferably set to about 60 to 100 μm, and when used in relatively large-sized electrical storage devices for power energy storage systems and in-vehicle applications, the total thickness is preferably set to about 100 to 300 μm.

[0105] In addition, from the viewpoint of more suitably exerting the effects of the present invention, the heat of fusion measured after heating the adhesive film 1 for metal terminals of the present invention at a temperature of 200°C, a surface pressure of 0.25 MPa, and for 16 seconds is preferably about 50 J / g or more, more preferably about 55 J / g or more, further preferably about 60 J / g or more, still further preferably 65 J / g or more. In addition, it is preferably about 100 J / g or less, more preferably about 90 J / g or less, further preferably about 80 J / g or less. As the preferred range, about 50 to 100 J / g, about 50 to 90 J / g, about 50 to 80 J / g, about 55 to 100 J / g, about 55 to 90 J / g, about 55 to 80 J / g, about 60 to 100 J / g, about 60 to 90 J / g, about 60 to 80 J / g, about 65 to 100 J / g, about 65 to 90 J / g, about 65 to 80 J / g, about 80 to 100 J / g can be cited. The heat of fusion of the adhesive film after heating can be adjusted by controlling the content ratio of polyethylene in the polypropylene film constituting the colored layer 11, the polymerization form (homopolymerization, block, or random), and the film-forming conditions (temperature and speed during film formation, cooling temperature and speed, etc.). The method for measuring the heat of fusion of the adhesive film after heating is as described below.

[0106] <Measurement of Heat of Fusion of Adhesive Film after Heating>

[0107] The adhesive film is heated at a temperature of 200°C, a surface pressure of 0.25 MPa, and for 16 seconds. This heat treatment assumes the physical properties after the adhesive film is disposed between the exterior material for electrical storage devices and the metal terminals and is heat-sealed. Then, the heat of fusion is measured in accordance with the provisions of JIS K 7122:2012. The measurement is performed using a differential scanning calorimeter. After maintaining the adhesive film 1 for metal terminals at -50°C for 15 minutes, it is heated from -50°C to 210°C at a heating rate of 10°C / minute, and the heat of fusion ΔH (J / g) for the first time is measured. Then, it is maintained at 210°C for 10 minutes. Next, it is cooled from 210°C to -50°C at a cooling rate of 10°C / minute and maintained at -50°C for 15 minutes. Further, it is heated from -50°C to 210°C at a heating rate of 10°C / minute, and the heat of fusion ΔH (J / g) for the second time is measured. In addition, the flow rate of nitrogen is set to 50 ml / minute. The value of the heat of fusion ΔH (J / g) measured for the first time through the above steps is used as the heat of fusion. The heat of fusion is the area enclosed by the baseline (a line formed by connecting the starting point and the ending point of the ridge line from the bottom line (base) to the bottom line) and the peak in the DSC curve.

[0108] In addition, from the viewpoint of more suitably exerting the effects of the present invention, the water vapor transmission rate of the adhesive film 1 for metal terminals of the present invention is preferably about 5.10 g·mm / (m 2· days) or less, more preferably about 4.50 g·mm / (m 2 · days) or less, further preferably about 4.30 g·mm / (m 2 · days) or less, further preferably about 4.10 g·mm / (m 2 · days) or less. Additionally, for example, it is about 2.0 g·mm / (m 2 · days) or more, about 0 g·mm / (m 2 · days) or more. As a preferred range, 0 to 5.10 g·mm / (m 2 · days) or so, 0 to 4.50 g·mm / (m 2 · days) or so, 0 to 4.30 g·mm / (m 2 · days) or so, 0 to 4.10 g·mm / (m 2 · days) or so, 2.0 to 5.10 g·mm / (m 2 · days) or so, 2.0 to 4.50 g·mm / (m 2 · days) or so, 2.0 to 4.30 g·mm / (m 2 · days) or so, 2.0 to 4.10 g·mm / (m 2 · days) or so. The method for measuring the water vapor transmission rate of the adhesive film is as described below.

[0109] <Measurement of the water vapor transmission rate of the adhesive film>

[0110] First, through the following steps, prepare an outer packaging material for an electrical storage device (hereinafter, sometimes simply referred to as "outer packaging material"). For example, as the base material layer, prepare a biaxially stretched polyethylene terephthalate (PET) film (thickness 12 μm) and a stretched nylon (ONy) film (thickness 15 μm). Bond the PET film and the ONy film using a two-component polyurethane adhesive (a polyol compound and an aromatic isocyanate compound), and perform an aging treatment to obtain a base material layer (thickness 30 μm) formed by sequentially laminating a PET film (thickness 12 μm) / an adhesive layer (cured thickness 3 μm) / an ONy film (thickness 15 μm) from the outside. Additionally, as the barrier layer, prepare an aluminum foil (JIS H4160: 1994 A8021H - O (thickness 40 μm)). Next, bond the surface of the ONy film side of the base material layer and the barrier layer using a two-component polyurethane adhesive (a polyol compound and an aromatic isocyanate compound), and perform an aging treatment to obtain a simulated outer packaging material for an electrical storage device (total thickness 73 μm) formed by sequentially laminating a base material layer (thickness 30 μm) / an adhesive layer (cured thickness 3 μm) / a barrier layer (thickness 40 μm), lacking the layer closer to the inside than the barrier layer.

[0111] Next, as Figure 9As shown in the schematic diagram, the obtained exterior material 3 is cut into a square with a longitudinal (MD) dimension of 120 mm and a transverse (TD) dimension of 120 mm ( Figure 9 as shown in (a)). In addition, prepare two pieces of the adhesive film 1 cut into a rectangle with a longitudinal (MD) dimension of 120 mm and a transverse (TD) dimension of 10 mm, and two pieces cut into a rectangle with a longitudinal (MD) dimension of 100 mm and a transverse (TD) dimension of 10 mm. On the barrier layer side of the exterior material 3, along the periphery of the exterior material 3, adhesive films with the same longitudinal length are arranged opposite to each other ( Figure 9 as shown in (b)). At this time, the second layer side of the adhesive film is made to be the barrier layer side of the exterior material 3. Then, a polytetrafluoroethylene film (PTFE film, thickness 100 μm) is placed on the adhesive film of this laminate (covering the surface of the adhesive film with the PTFE film), and it is placed on a press heated to 200 °C in the state of silicon wafer / PTFE / this laminate / PTFE / silicone sponge sheet, and left standing for 16 seconds under the condition of a pressure of 0.25 MPa to thermally bond the adhesive film and the exterior material 3. The thermally bonded laminate is naturally cooled to 25 °C, and the PTFE film is peeled off from the laminate. This heat treatment is to assume the physical properties after the adhesive film is arranged between the exterior material for the electrical storage device and the metal terminal and is thermally bonded. Next, with the adhesive film on the inside, the exterior material 3 is folded in half longitudinally ( Figure 9 as shown in (c)). Two pieces of the adhesive film for the metal terminal with a longitudinal (MD) dimension of 120 mm are arranged overlapping between the exterior materials 3 along the long side to be thermally sealed as described later. Two pieces of the adhesive film for the metal terminal with a longitudinal (MD) dimension of 100 mm are arranged folded in half between the exterior materials 3 along the short side to be thermally sealed as described later. The peripheral part of the exterior material 3 becomes a laminate formed by laminating the exterior material / adhesive film / adhesive film / exterior material in sequence ( Figure 9 as shown in (c)).

[0112] Next, using a heat-sealing bar (stainless steel plate), at the positions of the long side and the short side of the laminate, the layers of the laminate are thermally bonded to form a bag shape with one short side not thermally bonded ( Figure 9 as shown in (c)). The heat-sealing conditions are: for the long side, using a heat-sealing bar with a width of 7 mm, heat-sealing once under the conditions of a temperature of 190 °C, a surface pressure of 0.5 MPa, and 1.5 seconds ( Figure 9 as shown in s1 of (c)). In addition, for the short side, using a heat-sealing bar with a width of 7 mm, heat-sealing once under the conditions of a temperature of 190 °C, a surface pressure of 0.5 MPa, and 1.5 seconds ( Figure 9 as shown in s2 of (c)). It is dried in a drying chamber for 1 day. Then, from the position of the short side not thermally bonded, a liquid of ethylene carbonate:diethyl carbonate:dimethyl carbonate = 1:1:1 (volume ratio) (moisture content 0%) of about 3.0 g is injected ( Figure 9For the short side without heat fusion bonding in (d), it is heat-sealed in the same manner as the above-mentioned short side. Figure 9 In (e) of s3), a sealed bag is formed. Figure 9 In (e)). After leaving the sealed bag standing for 30 days in an environment of 65°C and 90% relative humidity, in a drying chamber, the moisture content of the liquid taken out from the sealed bag is measured by the Karl Fischer method to obtain the moisture content (ppm). From the obtained moisture content, the amount of electrolyte input (g), the permeation distance (mm), the permeation cross-sectional area (m 2 ), and the number of storage days (days), the water vapor transmission rate (g·mm / (m 2 ·day)) is calculated.

[0113] Water vapor transmission rate (g·mm / (m 2 ·day)) = [Obtained moisture content (ppm) × Input electrolyte (g) × Permeation distance (mm)] / [Permeation cross-sectional area (m 2 ) × Number of storage days (days)]

[0114] · Obtained moisture content (ppm): Obtained by the Karl Fischer method.

[0115] · Input electrolyte (g): 3.0 g

[0116] · Permeation distance (mm): Sealing part width 7 mm

[0117] · Permeation cross-sectional area (m 2 ): Residual thickness (μm) × Inner circumference of the sealing part 200 (mm)

[0118] · Number of storage days (days): 30 days

[0119] In addition, the heat shrinkage rate (length N after test / length M before test) of the adhesive film for metal terminals of the present invention is preferably 85% or more, more preferably 90% or more, and further preferably 95% or more. As a preferred range, it can be cited: about 85 - 100%, about 90 - 100%, about 95 - 100%. The higher the heat shrinkage rate (less likely to shrink thermally), the smaller the dimensional change when sealing with the metal tab, and the higher the dimensional accuracy of the tab lead that can be produced. For example, if a resin such as polyethylene naphthalate is used as the resin for forming the base material 14 described later, the heat shrinkage rate of the adhesive film can be increased. The method for measuring the heat shrinkage rate is as described below.

[0120] <Measurement of the heat shrinkage rate of the adhesive film>

[0121] Cut the adhesive film into a size of 120 mm (MD) × 120 mm (TD) in length as a test piece. Next, measure the length M (mm) of the test piece with a metal ruler. Next, fix the end of the test piece in the MD direction to the metal mesh with tape so that the test piece hangs down from the metal mesh. In this state, place it in an oven heated to 175 °C for 30 minutes, then take out the test piece together with the metal mesh and let it cool naturally in a room temperature (25 °C) environment. Next, measure the length N (mm) of the test piece that has been naturally cooled to room temperature with a metal ruler. Calculate the thermal shrinkage rate of the adhesive film for metal terminals by the following formula, and take the average value of n3 as the measurement result.

[0122] Thermal shrinkage rate (%) = (Length N after test / Length M before test) × 100

[0123] [Base material 14]

[0124] In the adhesive film 1 for metal terminals, the base material 14 is a layer that functions as a support for the adhesive film 1 for metal terminals and is provided as needed. For example, the colored layer 11 can also be set as the base material 14. For example, in the case of the adhesive film 1 for metal terminals with the base material as an intermediate layer, prepare a roll of this base material in advance, and use an extruder and a T-die casting device to extrude polypropylene or the like with a specified thickness on the surface of the base material unrolled from this roll, thereby enabling the production of the multi-layered adhesive film 1 for metal terminals.

[0125] The base material 14 can be formed by the above-mentioned colored layer 11, or can be formed by the above-mentioned first layer 12a, second layer 12b, third layer 12c, fourth layer 12d, etc.

[0126] The base material 14 can be formed by a resin film, for example. When laminating the base material 14 with the first layer 12a, etc. to manufacture the adhesive film 1 for metal terminals of the present invention, a pre-formed resin film can also be used as the base material 14. In addition, the resin forming the base material 14 can be made into a film on the surface of the first layer 12a, etc. by extrusion molding or coating, etc., as the base material 14 formed by a resin film.

[0127] There is no particular limitation on the raw material for forming the base material 14. As the raw material for forming the base material 14, for example, polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicone resins, phenolic resins, polyetherimides, polyimides, polycarbonates, and mixtures or copolymers thereof can be cited. Among these, polyolefin resins are particularly preferred. That is, the raw material for forming the base material 14 preferably includes resins containing a polyolefin backbone such as polyolefins and acid-modified polyolefins. The fact that the resin constituting the base material 14 contains a polyolefin backbone can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, etc.

[0128] The base material 14 preferably contains a polyolefin resin, preferably contains polyolefin, and more preferably is a layer formed of polyolefin. The layer formed of polyolefin may be a stretched polyolefin film or an unstretched polyolefin film, but an unstretched polyolefin film is preferred. As the polyolefin, specifically, polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, etc.; crystalline or amorphous polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene), etc.; and terpolymers of ethylene-butene-propylene, etc. Among these polyolefins, polyethylene and polypropylene are preferably mentioned, and polypropylene is more preferably mentioned. In addition, due to excellent electrolyte resistance, the base material 14 preferably contains homopolypropylene, more preferably is formed of homopolypropylene, and further preferably is an unstretched homopolypropylene film.

[0129] As the polyamide, specifically, aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, copolymers of nylon 6 and nylon 66, etc.; hexamethylenediamine-isophthalic acid-terephthalic acid copolyamides such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid), poly(m-xylylene adipamide) (MXD6), etc., which contain aromatic polyamides; alicyclic polyamides such as poly(aminomethylcyclohexyladipamide) (PACM6), etc.; and polyamides copolymerized with lactam components or isocyanate components such as 4,4'-diphenylmethane-diisocyanate, polyesteramide copolymers which are copolymers of copolyamides and polyesters or polyalkylene ether diols, or polyether ester amide copolymers; copolymers of these, etc. These polyamides may be used alone, or two or more of them may be used in combination.

[0130] As the polyester, specifically, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, a copolyester having ethylene terephthalate as a main repeating unit, a copolyester having butylene terephthalate as a main repeating unit, etc. can be mentioned. In addition, as the copolyester having ethylene terephthalate as a main repeating unit, specifically, a copolymer polyester obtained by polymerizing ethylene terephthalate as a main repeating unit and ethylene isophthalate (hereinafter, abbreviated in accordance with polyethylene glycol (terephthalate / isophthalate)), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium isophthalate sulfonate), polyethylene (terephthalate / sodium isophthalate sulfonate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decanedicarboxylate), etc. can be mentioned. In addition, as the copolyester having butylene terephthalate as a main repeating unit, specifically, a copolymer polyester obtained by polymerizing butylene terephthalate as a main repeating unit and butylene isophthalate (hereinafter, abbreviated in accordance with polybutylene glycol (terephthalate / isophthalate)), polybutylene glycol (terephthalate / adipate), polybutylene glycol (terephthalate / sebacate), polybutylene glycol (terephthalate / decanedicarboxylate), polybutylene naphthalate, etc. can be mentioned. These polyesters can be used alone or in combination of two or more.

[0131] In addition, the base material 14 can be formed of a nonwoven fabric made of the above resin. When the base material 14 is a nonwoven fabric, the base material 14 is preferably made of the above polyolefin resin, polyamide resin, etc.

[0132] The melting peak temperature of the base material 14 is preferably 120 °C or higher, more preferably about 130 °C or higher, and further preferably about 140 °C or higher. From the same perspective, the melting peak temperature is, for example, 270 °C or lower, preferably 210 °C or lower, preferably 200 °C or lower, more preferably 190 °C or lower, further preferably about 180 °C or lower, and further preferably about 170 °C or lower. As the preferred range of the melting peak temperature, 120 to 270 °C or so, 120 to 210 °C or so, 120 to 200 °C or so, 120 to 190 °C or so, 120 to 180 °C or so, 120 to 170 °C or so, 130 to 270 °C or so, 130 to 210 °C or so, 130 to 200 °C or so, 130 to 190 °C or so, 130 to 180 °C or so, 130 to 170 °C or so, 140 to 270 °C or so, 140 to 210 °C or so, 140 to 200 °C or so, 140 to 190 °C or so, 140 to 180 °C or so, 140 to 170 °C or so can be cited.

[0133] The base material 14 can be a single layer or a multi-layer.

[0134] In addition, by incorporating a colorant into the base material 14, the base material 14 can also be made into a layer containing the colorant. However, in this case, it is desirable to form a colored layer 11 with a thickness of 50 μm or less so that the metal terminal adhesive film 1 does not contain a colored layer with a thickness exceeding 50 μm. The base material 14 can also be a resin with low transparency to adjust the light transmittance. When the base material 14 is a film, a colored film or a film with low transparency can also be used. In addition, when the base material 14 is a non-woven fabric, fibers containing a colorant, a non-woven fabric using an adhesive, or a non-woven fabric with low transparency can be used.

[0135] When the base material 14 is composed of a resin film, known adhesion-promoting means such as corona discharge treatment, ozone treatment, and plasma treatment can be performed on the surface of the base material 14 as needed.

[0136] In addition, from the perspective of more appropriately exerting the effects of the present invention, the thickness of the base material 14 is preferably about 20 μm or more, more preferably about 30 μm or more, and further preferably about 40 μm or more. In addition, it is preferably about 120 μm or less, more preferably about 110 μm or less, and further preferably 100 μm or less. As the preferred range of the thickness of the base material 14, 20 to 120 μm or so, 20 to 110 μm or so, 20 to 100 μm or so, 30 to 120 μm or so, 30 to 110 μm or so, 30 to 100 μm or so, 40 to 120 μm or so, 40 to 110 μm or so, 40 to 100 μm or so can be cited.

[0137] [Adhesion promoter layer 13]

[0138] The adhesion promoter layer 13 is a layer provided as needed for the purpose of firmly adhering the coloring layer 11 to the first layer 12a and the coloring layer 11 to the second layer 12b (see Figure 7 ). The adhesion promoter layer 13 may be provided only on one side between the coloring layer 11 and the first layer 12a and the second layer 12b, or may be provided on both sides.

[0139] 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 adhesion promoters. From the viewpoint of obtaining strong adhesion strength, among these, an adhesion promoter formed from an isocyanate-based adhesion promoter is preferred. As the isocyanate-based adhesion promoter, an adhesion promoter layer composed of an isocyanate component selected from triisocyanate monomers and polymeric MDI has excellent lamination strength and little reduction in lamination strength at high temperatures. In particular, it is particularly preferred to form using an adhesion promoter composed of triphenylmethane-4,4',4"-triisocyanate as the triisocyanate monomer or polymethylene polyphenyl polyisocyanate (NCO content is about 30%, viscosity is 200 to 700 mPa·s) as the polymeric MDI. In addition, it is also preferred to form using tris(4-isocyanatophenyl) thiophosphate as the triisocyanate monomer or a two-component curable adhesion promoter with a polyethyleneimine-based main agent and polycarbodiimide as the crosslinking agent.

[0140] The adhesion promoter layer 13 can be formed by coating and drying using known coating methods such as bar coating, roll coating, and gravure coating. As the coating amount of the adhesion promoter, in the case of an adhesion promoter composed of triisocyanate, it is about 20 to 100 mg / m 2 and preferably about 40 to 60 mg / m 2 ; in the case of an adhesion promoter composed of polymeric MDI, it is about 40 to 150 mg / m 2 and preferably about 60 to 100 mg / m 2 ; in the case of a two-component curable adhesion promoter with a polyethyleneimine-based main agent and polycarbodiimide as the crosslinking agent, it is about 5 to 50 mg / m 2 and preferably about 10 to 30 mg / m 2 . In addition, the triisocyanate monomer is a monomer having three isocyanate groups in one molecule, and the polymeric MDI is a mixture of MDI and MDI oligomers polymerized from MDI, and is represented by the following formula.

[0141]

[0142] From the viewpoint of more suitably exerting the effects of the present invention, it is preferable that the first layer 12a is in surface contact with the colored layer 11, and the second layer 12b is in surface contact with the colored layer 11.

[0143] As a specific example of the preferable laminated structure of the adhesive film 1 for metal terminals of the present invention, there can be mentioned: a three-layer structure formed by sequentially laminating a first layer 12a made of polypropylene / a colored layer 11 made of polypropylene / a second layer 12b made of acid-modified polypropylene; a three-layer structure formed by sequentially laminating a first layer 12a made of acid-modified polypropylene / a colored layer 11 made of polypropylene / a second layer 12b made of acid-modified polypropylene; a four-layer structure formed by sequentially laminating a first layer 12a made of polypropylene / a colored layer 11 made of polypropylene / a third layer 12c made of polypropylene / a second layer 12b made of acid-modified polypropylene; a four-layer structure formed by sequentially laminating a first layer 12a made of acid-modified polypropylene / a colored layer 11 made of polypropylene / a third layer 12c made of polypropylene / a second layer 12b made of acid-modified polypropylene, etc.

[0144] The adhesive film 1 for metal terminals of the present invention is preferably formed of a polyolefin resin. For example, the resin component contained in the adhesive film 1 for metal terminals of the present invention is preferably only a polyolefin resin, more preferably only an acid-modified polyolefin and a polyolefin, and further preferably only an acid-modified polypropylene and a polypropylene. The preferable acid-modified polyolefin and polyolefin are as described above.

[0145] As a method of disposing the adhesive film 1 for metal terminals between the metal terminal 2 and the exterior material 3 for electrical storage devices, there is no particular limitation. For example, as Figures 1 to 3 shown, in the portion where the metal terminal 2 is clamped by the exterior material 3 for electrical storage devices, the adhesive film 1 for metal terminals can be wound around the metal terminal 2. Additionally, omitting the illustration, in the portion where the metal terminal 2 is clamped by the exterior material 3 for electrical storage devices, the adhesive film 1 for metal terminals can be disposed on both sides of the metal terminal 2 so as to straddle two metal terminals 2.

[0146] [Metal terminal 2]

[0147] The adhesive film 1 for metal terminals of the present invention is used by being disposed between the metal terminal 2 and the exterior material 3 for electrical storage devices. The metal terminal 2 (tab) is a conductive member electrically connected to the electrode (positive electrode or negative electrode) of the electrical storage device element 4 and is made of a metal material. As the metal material constituting the metal terminal 2, there is no particular limitation. For example, aluminum, nickel, copper, etc. can be mentioned. For example, the metal terminal 2 connected to the positive electrode of a lithium-ion electrical storage device is usually made of aluminum, etc. Additionally, the metal terminal 2 connected to the negative electrode of a lithium-ion electrical storage device is usually made of copper, nickel, etc.

[0148] From the viewpoint of improving electrolyte resistance, the surface of the metal terminal 2 is preferably subjected to a chemical surface treatment. For example, when the metal terminal 2 is formed of aluminum, as a specific example of the chemical surface treatment, known methods for forming a corrosion-resistant coating film such as phosphate, chromate, fluoride, triazine thiol compound, etc. can be cited. Among the methods for forming a corrosion-resistant coating film, a phosphoric acid chromate treatment using a substance composed of three components of phenolic resin, chromium(III) fluoride compound, and phosphoric acid is also suitable.

[0149] The size of the metal terminal 2 can be appropriately set according to the size of the electrical storage device used, etc. As the thickness of the metal terminal 2, it can be cited that it is preferably about 50 to 1000 μm, more preferably about 70 to 800 μm. In addition, as the length of the metal terminal 2, it can be cited that it is preferably about 1 to 200 mm, more preferably about 3 to 150 mm. In addition, as the width of the metal terminal 2, it can be cited that it is preferably about 1 to 200 mm, more preferably about 3 to 150 mm.

[0150] [Outer packaging material 3 for electrical storage device]

[0151] As the outer packaging material 3 for the electrical storage device, materials having a laminated structure formed 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 can be cited. Figure 8 In one example of the cross-sectional structure of the outer packaging material 3 for the electrical storage device, a method of laminating a base material layer 31, an adhesive layer 32 provided as needed, a barrier layer 33, an adhesive layer 34 provided as needed, and a heat-sealable resin layer 35 in this order is shown. In the outer packaging material 3 for the electrical storage device, the base material layer 31 is on the outer layer side, and the heat-sealable resin layer 35 is on the innermost layer. When assembling the electrical storage device, the heat-sealable resin layers 35 located on the periphery of the electrical storage device element 4 are brought into surface contact with each other for heat sealing, thereby sealing the electrical storage device element 4 and encapsulating the electrical storage device element 4. In addition, in Figures 1 to 3 the electrical storage device 10 when using the embossed type outer packaging material 3 for the electrical storage device obtained by molding such as embossing is shown, but the outer packaging material 3 for the electrical storage device can also be an unformed bag type. In addition, among the bag types, there are three-side seals, four-side seals, pillow types, etc., and any type can be used.

[0152] The thickness of the laminate that constitutes the exterior material 3 for the electrical storage device is not particularly limited. Regarding the upper limit, from the viewpoints of cost reduction, energy density improvement, etc., 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, about 120 μm or less can be cited. Regarding the lower limit, from the viewpoint of maintaining the function of the exterior material 3 for the electrical storage device such as protecting the electrical storage device element 4, preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, about 80 μm or more can be cited. Regarding the preferred range, for example, about 35 - 190 μm, about 35 - 180 μm, about 35 - 160 μm, about 35 - 155 μm, about 35 - 140 μm, about 35 - 130 μm, about 35 - 120 μm, about 45 - 190 μm, about 45 - 180 μm, about 45 - 160 μm, about 45 - 155 μm, about 45 - 140 μm, about 45 - 130 μm, about 45 - 120 μm, about 60 - 190 μm, about 60 - 180 μm, about 60 - 160 μm, about 60 - 155 μm, about 60 - 140 μm, about 60 - 130 μm, about 60 - 120 μm, about 80 - 190 μm, about 80 - 180 μm, about 80 - 160 μm, about 80 - 155 μm, about 80 - 140 μm, about 80 - 130 μm, about 80 - 120 μm can be cited.

[0153] (Base material layer 31)

[0154] In the exterior material 3 for the electrical storage device, the base material layer 31 is a layer that functions as the base material of the exterior material for the electrical storage device and is the layer that forms the outermost layer side.

[0155] Regarding the raw material for forming the base material layer 31, there is no particular limitation as long as it has insulating properties. As the raw material for forming the base material layer 31, for example, polyester, polyamide, epoxy, acrylic resin, fluororesin, polyurethane, silicone resin, phenol resin, polyetherimide, polyimide, and mixtures or copolymers thereof can be cited. Polyesters such as polyethylene terephthalate and polybutylene terephthalate have the advantages of excellent electrolyte resistance and being less likely to turn white due to the attachment of the electrolyte, and are suitable for use as the raw material for forming the base material layer 31. In addition, the polyamide film has excellent stretchability and can prevent the occurrence of whitening caused by resin cracking of the base material layer 31 during molding, and is suitable for use as the raw material for forming the base material layer 31.

[0156] The base material layer 31 can be formed of a resin film that is uniaxially or biaxially stretched, or can also be formed of an unstretched resin film. Among them, a resin film that is uniaxially or biaxially stretched, particularly a biaxially stretched resin film, has improved heat resistance through orientation crystallization, and is thus suitable for use as the base material layer 31.

[0157] Among these, as the resin film forming the base material layer 31, nylon and polyester are preferably listed, and biaxially stretched nylon and biaxially stretched polyester are more preferably listed.

[0158] In the base material layer 31, in order to improve the pinhole resistance and insulation when used as a package for an electrical storage device, resin films of different raw materials can also be laminated. Specifically, a multilayer structure formed by laminating a polyester film and a nylon film, a multilayer structure formed by laminating a biaxially stretched polyester and a biaxially stretched nylon, etc. can be listed. When the base material layer 31 is formed into a multilayer structure, the respective resin films can be bonded via an adhesive, or can also be directly laminated without an adhesive. In the case of not bonding via an adhesive, methods of bonding in a thermally molten state such as coextrusion, sandwich lamination, and thermal lamination can be listed, for example.

[0159] In addition, the base material layer 31 can be made low-friction in order to improve formability. In the case of making the base material layer 31 low-friction, there is no particular limitation on the coefficient of friction of its surface, and for example, 1.0 or less can be listed. In order to make the base material layer 31 low-friction, for example, matting treatment, formation of a thin film layer of a slip agent, a combination of these, etc. can be listed.

[0160] Regarding the thickness of the base material layer 31, for example, about 10 to 50 μm, preferably about 15 to 30 μm can be listed.

[0161] (Adhesive layer 32)

[0162] In the exterior material 3 for an electrical storage device, the adhesive layer 32 is a layer that is disposed on the base material layer 31 as needed in order to impart adhesiveness 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.

[0163] The adhesive layer 32 is formed of an adhesive that can bond the base material layer 31 and the barrier layer 33. The adhesive used in the formation of the adhesive layer 32 can be a two-component curable adhesive, or can also be a one-component curable adhesive. In addition, there is no particular limitation on the bonding mechanism of the adhesive used in the formation of the adhesive layer 32, and it can be any mechanism such as a chemical reaction type, a solvent evaporation type, a thermal melting type, a hot pressing type, etc.

[0164] As the resin component of the adhesive that can be used in the formation of the adhesive layer 32, from the viewpoints of excellent spreadability, durability under high humidity conditions, yellowing inhibition effect, heat deterioration inhibition effect during heat sealing, etc., and effectively suppressing the occurrence of delamination by suppressing the reduction of the lamination strength between the base material layer 31 and the barrier layer 33, the following are preferably listed: two-component curable polyurethane adhesives; polyamides, polyesters, or blended resins of these with modified polyolefins.

[0165] In addition, the adhesive layer 32 can also be multi-layered with different adhesive components. When the adhesive layer 32 is multi-layered with different adhesive components, from the viewpoint of improving the lamination strength between the base material layer 31 and the barrier layer 33, it is preferable to select a resin with excellent adhesiveness to the base material layer 31 as the adhesive component disposed on the side of the base material layer 31, and to select an adhesive component with excellent adhesiveness to the barrier layer 33 as the adhesive component disposed on the side of the barrier layer 33. When the adhesive layer 32 is multi-layered with different adhesive components, specifically, as the adhesive component disposed on the side of the barrier layer 33, the following are preferably listed: acid-modified polyolefins, metal-modified polyolefins, mixed resins of polyesters and acid-modified polyolefins, copolyester resins, etc.

[0166] Regarding the thickness of the adhesive layer 32, for example, it can be about 2 to 50 μm, preferably about 3 to 25 μm.

[0167] (Barrier layer 33)

[0168] In the exterior material 3 for electrical storage devices, the barrier layer 33 is a layer that, in addition to improving the strength of the exterior material for electrical storage devices, also has the function of preventing the intrusion of water vapor, oxygen, light, etc. into the interior of the electrical storage device. The barrier layer 33 is preferably a metal layer, i.e., a layer formed of a metal. Specifically, as the metal constituting the barrier layer 33, aluminum, stainless steel, titanium, etc. can be listed, and aluminum is preferably listed. The barrier layer 33 can be formed, for example, by a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, a film provided with these vapor deposition films, etc., and is preferably formed by a metal foil, and more preferably formed by an aluminum foil. When manufacturing the exterior material for electrical storage devices, from the viewpoint of preventing wrinkles or pinholes from occurring in the barrier layer 33, the barrier layer is more preferably formed of 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).

[0169] Regarding the thickness of the barrier layer 33, from the viewpoints of thinning the exterior material for the electrical storage device and making it less likely to form pinholes even after molding, values of about 10 to 200 μm, more preferably about 20 to 100 μm, about 20 to 45 μm, about 45 to 65 μm, and about 65 to 85 μm can be preferably cited.

[0170] In addition, in order to stabilize adhesion and prevent dissolution or corrosion, etc., the barrier layer 33 is preferably surface-treated by a chemical method on at least one surface, preferably on both surfaces. Here, the chemical surface treatment refers to a treatment for forming a corrosion-resistant coating film on the surface of the barrier layer.

[0171] (Adhesive layer 34)

[0172] In the exterior material 3 for the electrical storage device, the adhesive layer 34 is a layer provided between the barrier layer 33 and the heat-sealable resin layer 35 as needed in order to firmly bond the heat-sealable resin layer 35.

[0173] The adhesive layer 34 is formed by an adhesive capable of bonding the barrier layer 33 and the heat-sealable resin layer 35. There is no particular limitation on the composition of the adhesive used for forming the adhesive layer. For example, a resin composition containing an acid-modified polyolefin can be cited. As the acid-modified polyolefin, the same substances as those exemplified in the first layer 12a and the second layer 12b can be exemplified.

[0174] Regarding the thickness of the adhesive layer 34, for example, values of about 1 to 40 μm, preferably about 2 to 30 μm can be cited.

[0175] (Heat-sealable resin layer 35)

[0176] In the exterior material 3 for the electrical storage device, the heat-sealable resin layer 35 corresponds to the innermost layer and is a layer that heat-seals the electrical storage device elements by heat-sealing heat-sealable resin layers to each other during the assembly of the electrical storage device.

[0177] Regarding the resin component used for the heat-sealable resin layer 35, there is no particular limitation as long as it can be heat-sealed. For example, polyolefins and cyclic polyolefins can be cited.

[0178] Specific examples of the above polyolefins include: polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylene 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 terpolymers of ethylene-butene-propylene. Among these polyolefins, polyethylene and polypropylene are also preferably cited.

[0179] The above-mentioned cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of the olefin as a constituent monomer of the above-mentioned cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, isoprene, etc. In addition, examples of the cyclic monomer as a constituent monomer of the above-mentioned cyclic polyolefin include cyclic olefins such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene, etc. Among these polyolefins, cyclic olefins can be preferably cited, and norbornene is further preferred. Styrene can also be cited as a constituent monomer.

[0180] Among these resin components, crystalline or amorphous polyolefins, cyclic polyolefins, and blended polymers thereof are also preferably cited; polyethylene, polypropylene, a copolymer of ethylene and norbornene, and a blended polymer of two or more of these are further preferred.

[0181] The heat-sealable resin layer 35 can be formed solely of one resin component, or can be formed of a blended polymer composed of a combination of two or more resin components. In addition, the heat-sealable resin layer 35 can be formed of only one layer, but can also be formed of two or more layers of the same or different resin components. If the second layer 12b has the same resin as the heat-sealable resin layer 35, the adhesion between these layers is improved, which is particularly preferred.

[0182] In addition, the thickness of the heat-sealable resin layer 35 is not particularly limited, and can be about 2 to 2000 μm, preferably about 5 to 1000 μm, and further preferably about 10 to 500 μm. In addition, the thickness of the heat-sealable resin layer 35 can be, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. In addition, for example, when the thickness of the adhesive layer 34 described later is 10 μm or more, the thickness of the heat-sealable resin layer 35 can be 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 later is less than 10 μm or when the adhesive layer 34 is not provided, the thickness of the heat-sealable resin layer 35 can be preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[0183] The exterior material for a storage device of the present invention can also be in the form of a kit including the exterior material for a storage device for a storage device and the adhesive film for metal terminals of the present invention. In this case, the storage devices to which it applies include: a storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an exterior material for a storage device that encapsulates the storage device element; and metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the exterior material for a storage device. When the kit of the present invention is used, it is used in such a manner that the adhesive film for metal terminals of the present invention is located between the metal terminal and the exterior material for a storage device.

[0184] 2. Electrical Storage Device

[0185] The electrical storage device 10 of the present invention includes: an electrical storage device element 4 having at least a positive electrode, a negative electrode, and an electrolyte; an exterior material 3 for the electrical storage device that encapsulates the electrical 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 3 for the electrical storage device. In the electrical storage device 10 of the present invention, it is characterized in that there is an adhesive film 1 for the metal terminal of the present invention between the metal terminal 2 and the exterior material 3 for the electrical storage device. That is, the electrical storage device 10 of the present invention can be manufactured by a method including a process of making the adhesive film 1 for the metal terminal of the present invention exist between the metal terminal 2 and the exterior material 3 for the electrical storage device.

[0186] Specifically, by using the exterior material 3 for the electrical storage device to encapsulate the electrical storage device element 4 having at least a positive electrode, a negative electrode, and an electrolyte in a state where the metal terminals 2 connected to the positive electrode and the negative electrode respectively protrude to the outside, and making the adhesive film 1 for the metal terminal of the present invention be located between the metal terminal 2 and the heat-fusible resin layer 35, the flange portion (the region where the heat-fusible resin layers 35 contact each other, the peripheral portion 3a of the exterior material 3 for the electrical storage device) of the exterior material 3 for the electrical storage device can be formed at the periphery of the electrical storage device element 4, and the heat-fusible resin layers 35 of the flange portion are heat-sealed to be sealed, thereby an electrical storage device 10 using the exterior material 3 for the electrical storage device can be provided. In addition, when the exterior material 3 for the electrical storage device is used to accommodate the electrical storage device element 4, it is used in such a way that the heat-fusible resin layer 35 of the exterior material 3 for the electrical storage device becomes the inner side (the surface in contact with the electrical storage device element 4).

[0187] The exterior material for the electrical storage device of the present invention can be suitably used for electrical storage devices such as batteries (including condensers, capacitors, etc.). Moreover, the exterior material for the electrical storage device of the present invention can be used for either a primary battery or a secondary battery, and is preferably a secondary battery. Regarding the types of secondary batteries to which the exterior material for the electrical storage device of the present invention can be applied, there is no particular limitation, and examples include lithium-ion batteries, lithium-ion polymer batteries, all-solid 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, capacitors, etc. Among these secondary batteries, lithium-ion batteries and lithium-ion polymer batteries can also be cited as preferred application objects of the exterior material for the electrical storage device of the present invention.

[0188] Examples

[0189] Examples and comparative examples are listed below to describe the present invention in detail. However, the present invention is not limited to the examples.

[0190] <Manufacture of Adhesive Film for Metal Terminals>

[0191] Example 1

[0192] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 80 μm) as a substrate, polypropylene containing carbon black (h-PP layer (homopolypropylene layer), melting peak temperature 162 °C, thickness 20 μm) as a black colored layer, maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 °C, thickness 40 μm) as the second layer on the metal terminal side, and on the other surface, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 60 μm) as the first layer on the outer packaging material side are extruded to obtain an adhesive film (total thickness 200 μm) formed by laminating the first layer (r-PP layer, thickness 60 μm) / substrate (CPP layer, thickness 80 μm) / colored layer (h-PP layer, thickness 20 μm) / second layer (r-PPa layer, thickness 40 μm) in sequence.

[0193] In addition, in each of the examples and comparative examples, in the adhesive film, the island portion ratio of the sea-island structure of the colored layer described later and the soft segment component ratio of the adhesive film are adjusted by controlling the polyethylene content, polymerization form (homopolymerization, block or random), and film-forming conditions (temperature and speed during film formation, cooling temperature and speed, etc.) in the colored layer.

[0194] Example 2

[0195] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 80 μm) as a substrate, polypropylene containing carbon black (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 20 μm) as a black colored layer, maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 °C, thickness 40 μm) as the second layer on the metal terminal side, and on the other surface, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 60 μm) as the first layer on the outer packaging material side are extruded to obtain an adhesive film (total thickness 200 μm) formed by laminating the first layer (r-PP layer, thickness 60 μm) / substrate (CPP layer, thickness 80 μm) / colored layer (r-PP layer, thickness 20 μm) / second layer (r-PPa layer, thickness 40 μm) in sequence.

[0196] Example 3

[0197] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 80 μm) as a substrate, polypropylene containing carbon black (h-PP layer (homopolypropylene layer), melting peak temperature 162 °C, thickness 30 μm) as a black colored layer, maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 °C, thickness 30 μm) as the second layer on the metal terminal side are extruded, and on the other surface, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 60 μm) as the first layer on the outer packaging material side is extruded to obtain an adhesive film (total thickness 200 μm) formed by laminating the first layer (r-PP layer, thickness 60 μm) / substrate (CPP layer, thickness 80 μm) / colored layer (h-PP layer, thickness 30 μm) / second layer (r-PPa layer, thickness 30 μm) in sequence.

[0198] Example 4

[0199] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 80 μm) as a substrate, polypropylene containing carbon black (h-PP layer (homopolypropylene layer), melting peak temperature 162 °C, thickness 40 μm) as a black colored layer, maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 °C, thickness 30 μm) as the second layer on the metal terminal side are extruded, and on the other surface, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 50 μm) as the first layer on the outer packaging material side is extruded to obtain an adhesive film (total thickness 200 μm) formed by laminating the first layer (r-PP layer, thickness 50 μm) / substrate (CPP layer, thickness 80 μm) / colored layer (h-PP layer, thickness 40 μm) / second layer (r-PPa layer, thickness 30 μm) in sequence.

[0200] Example 5

[0201] Using an extruder and a T-die casting device, on one side of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 80 μm) as a substrate, polypropylene containing carbon black (h-PP layer (homopolypropylene layer), melting peak temperature 162 °C, thickness 40 μm) as a black colored layer, maleic anhydride modified polypropylene (r-PPa layer (maleic anhydride modified random polypropylene layer), melting peak temperature 140 °C, thickness 40 μm) as the second layer on the metal terminal side are extruded, and on the other side, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 40 μm) as the first layer on the outer packaging material side is extruded to obtain an adhesive film (total thickness 200 μm) formed by laminating the first layer (r-PP layer, thickness 40 μm) / substrate (CPP layer, thickness 80 μm) / colored layer (h-PP layer, thickness 40 μm) / second layer (r-PPa layer, thickness 40 μm) in sequence.

[0202] Example 6

[0203] As a multi-layer air-cooled blow molding, a polypropylene film (PP layer) of polypropylene layer containing titanium oxide as a gray colored layer, melting peak temperature 160 °C, thickness 30 μm), maleic anhydride modified polypropylene (r-PPa layer (maleic anhydride modified random polypropylene layer), melting peak temperature 140 °C, thickness 50 μm) as the second layer on the metal terminal side, and polypropylene (r-PP layer (random polypropylene layer, melting peak temperature 140 °C, thickness 20 μm)) as the first layer on the outer packaging material side are molded to obtain an adhesive film for metal terminals (total thickness 100 μm) formed by laminating the first polyolefin layer (PP layer thickness 20 μm) / substrate (PP layer thickness 30 μm) / second polyolefin layer (PPa layer thickness 50 μm) in sequence.

[0204] Example 7

[0205] Using multi-layer air-cooled blow molding, a polypropylene film (PP layer) containing titanium oxide as a gray-colored layer, with a melting peak temperature of 160 °C and a thickness of 20 μm, a maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), with a melting peak temperature of 140 °C and a thickness of 40 μm) as the second layer on the metal terminal side, a polypropylene (r-PP layer (random polypropylene layer), with a melting peak temperature of 140 °C and a thickness of 35 μm), a polypropylene (r-PP layer (random polypropylene layer), with a melting peak temperature of 140 °C and a thickness of 20 μm) as the first layer on the outer packaging material side, and a polypropylene (r-PP layer (random polypropylene layer), with a melting peak temperature of 140 °C and a thickness of 35 μm) are molded to obtain an adhesive film (total thickness 150 μm) formed by laminating the PP layer (thickness 20 μm) / PP layer (thickness 35 μm) / PP layer (thickness 20 μm) / PP layer (thickness 35 μm) / PPa layer (thickness 40 μm) in sequence.

[0206] Example 8

[0207] Using an extruder and a T-die casting device, on one surface of a polyethylene naphthalate (PEN layer, melting peak temperature 260 °C, thickness 80 μm) as a substrate, a polypropylene containing carbon black (h-PP layer (homopolypropylene layer), melting peak temperature 162 °C, thickness 20 μm) as a black-colored layer and a maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 °C, thickness 40 μm) as the second layer on the metal terminal side are extruded, and on the other surface, a polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 60 μm) as the first layer on the outer packaging material side is extruded to obtain an adhesive film (total thickness 200 μm) formed by laminating the first layer (r-PP layer, thickness 60 μm) / substrate (PEN layer, thickness 80 μm) / colored layer (h-PP layer, thickness 20 μm) / second layer (r-PPa layer, thickness 40 μm) in sequence.

[0208] Comparative Example 1

[0209] Using an extruder and a T-die casting device, a polypropylene film (PP layer (polypropylene layer), polypropylene, melting peak temperature 160°C, thickness 70 μm) of a polypropylene layer containing titanium oxide as a gray-colored layer, and maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140°C) as the second layer on the metal terminal side were extruded with a thickness of 70 μm. On the other side, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140°C) as the first layer on the outer packaging material side was co-extruded with a thickness of 60 μm to obtain an adhesive film (total thickness 200 μm) formed by laminating the first layer (r-PP layer (random polypropylene layer), thickness 60 μm) / polypropylene layer (PP layer, thickness 70 μm) / second layer (r-PPa layer, thickness 70 μm) in sequence.

[0210] Comparative Example 2

[0211] Using an extruder and a T-die casting device, a polypropylene film (PP layer (homopolypropylene layer), polypropylene, melting peak temperature 160°C, thickness 60 μm) of a polypropylene layer containing titanium oxide as a gray-colored layer, and maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140°C) as the second layer on the metal terminal side were extruded with a thickness of 50 μm. On the other side, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140°C) as the first layer on the outer packaging material side was co-extruded with a thickness of 40 μm to obtain an adhesive film (total thickness 150 μm) formed by laminating the first layer (r-PP layer (random polypropylene layer), thickness 40 μm) / polypropylene layer (PP layer, thickness 60 μm) / second layer (r-PPa layer, thickness 50 μm) in sequence.

[0212] Comparative Example 3

[0213] Using an extruder and a T-die casting device, on one side of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160°C, thickness 80 μm) as a substrate, maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140°C, thickness 60 μm) containing carbon black as a black-colored layer (substrate) on the metal terminal side was extruded. On the other side, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140°C, thickness 60 μm) as the first layer on the outer packaging material side was extruded to obtain an adhesive film (total thickness 200 μm) formed by laminating the first layer (r-PP layer, thickness 60 μm) / substrate (CPP layer, thickness 80 μm) / colored layer (second layer) (r-PPa layer, thickness 60 μm) in sequence.

[0214] Comparative Example 4

[0215] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 50 μm) as a substrate, an acrylated polypropylene (r-PPa layer (acrylated random polypropylene layer), melting peak temperature 140 °C, thickness 100 μm) containing carbon black and serving as a second layer on the metal terminal side and being a colored layer (substrate) is extruded. On the other surface, a polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 50 μm) serving as a first layer on the outer packaging material side is extruded, obtaining an adhesive film (total thickness 200 μm) formed by laminating in sequence the first layer (r-PP layer, thickness 50 μm) / substrate (CPP layer, thickness 50 μm) / colored layer (second layer) (r-PPa layer, thickness 100 μm).

[0216] Comparative Example 5

[0217] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 50 μm) as a substrate, an acrylated polypropylene (r-PPa layer (acrylated random polypropylene layer), melting peak temperature 140 °C, thickness 50 μm) containing carbon black and serving as a second layer on the metal terminal side and being a colored layer (substrate) is extruded. On the other surface, a polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 100 μm) serving as a first layer on the outer packaging material side is extruded, obtaining an adhesive film (total thickness 200 μm) formed by laminating in sequence the first layer (r-PP layer, thickness 100 μm) / substrate (CPP layer, thickness 50 μm) / colored layer (second layer) (r-PPa layer, thickness 50 μm).

[0218] Comparative Example 6

[0219] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 67 μm) as a substrate, an anthracene black-containing maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 °C, thickness 67 μm) as a second layer on the metal terminal side and as a colored layer (substrate) is extruded, and on the other surface, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 67 μm) as a first layer on the exterior material side is extruded to obtain an adhesive film (total thickness 201 μm) formed by sequentially laminating the first layer (r-PP layer, thickness 67 μm) / substrate (CPP layer, thickness 67 μm) / colored layer (second layer) (r-PPa layer, thickness 67 μm).

[0220] Comparative Example 7

[0221] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 50 μm) as a substrate, an anthracene black-containing maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 °C, thickness 50 μm) as a second layer on the metal terminal side and as a colored layer (substrate) is extruded, and on the other surface, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 50 μm) as a first layer on the exterior material side is extruded to obtain an adhesive film (total thickness 150 μm) formed by sequentially laminating the first layer (r-PP layer, thickness 50 μm) / substrate (CPP layer, thickness 50 μm) / colored layer (second layer) (r-PPa layer, thickness 50 μm).

[0222] Comparative Example 8

[0223] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 50 μm) as a substrate, maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 °C, thickness 50 μm) as a second layer on the metal terminal side is extruded, and on the other surface, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 50 μm) containing anthracene black and serving as a colored layer (substrate) and as a colored layer (first layer) on the exterior material side is extruded to obtain an adhesive film (total thickness 150 μm) formed by sequentially laminating the colored layer (first layer) (r-PP layer, thickness 50 μm) / substrate (CPP layer, thickness 50 μm) / second layer (r-PPa layer, thickness 50 μm).

[0224] Comparative Example 9

[0225] Using an extruder and a T-die casting device, on one surface of a polypropylene film (CPP layer (unstretched homopolypropylene layer), melting peak temperature 160 °C, thickness 80 μm) as the substrate, maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer), melting peak temperature 140 °C, thickness 60 μm) as the second layer on the metal terminal side is extruded. On the other surface, polypropylene (r-PP layer (random polypropylene layer), melting peak temperature 140 °C, thickness 60 μm) containing carbon black as the first layer on the outer packaging material side and serving as the black colored layer (substrate) is extruded, obtaining an adhesive film (total thickness 200 μm) formed by laminating the colored layer (first layer) (r-PP layer, thickness 60 μm) / substrate (CPP layer, thickness 80 μm) / second layer (r-PPa layer, thickness 60 μm) in sequence.

[0226] <Measurement of softening point>

[0227] The softening points of each layer were measured by the following method. The results are shown in Table 1. The measuring device used was nanoTA manufactured by ANASYS INSTRUMENT, and the thermal probe used was PR-EX-AN2-300-5 manufactured by ANASYS INSTRUMENTS. Calibration was carried out through the following process before measurement. The standard specimens were polycaprolactone (softening point: 55 °C), polyethylene (softening point: 116 °C), and polyethylene terephthalate (softening point: 235 °C) with known softening points. While heating with the surface of each standard specimen in contact with the thermal probe, the thermal expansion directly below the thermal probe was measured during heating, and a curve graph representing the deflection with respect to Voltage was obtained. The measurement conditions set in the device are as follows.

[0228] Measurement start temperature: 0.1 V

[0229] Measurement end temperature: 10 V

[0230] Heating rate: 0.2 V / sec

[0231] Using the softening points of each standard specimen, the curve graph representing the displacement of the thermal probe with respect to potential was converted into a curve graph representing the displacement with respect to temperature. After calibration, the thermal probe was brought into contact with the measurement site of the cross-section of the specimen formed with a diamond knife or the like after being embedded in the resin. Then, while in contact with the thermal probe, heating was carried out under the following conditions to obtain a curve graph representing the displacement of the thermal probe with respect to temperature (thermal expansion curve).

[0232] Measurement start temperature: 40 °C

[0233] Measurement end temperature: 350 °C

[0234] Heating rate: 5 °C / sec

[0235] In the obtained thermal expansion curve, obtain the temperature at the vertex of the curve. Perform the above measurement at any 5 points. Take the average value of the obtained temperatures as the softening point. The results are shown in Table 1.

[0236] <Measurement of melting peak temperature>

[0237] The melting peak temperature is measured by the following method. The results are shown in Table 1. For each adhesive film 1, the melting peak temperature is measured in accordance with the provisions of JIS K7121:2012 (Method for measuring the transition temperature of plastics (Addendum 1 to JIS K7121:1987)). The measurement is carried out using a differential scanning calorimeter (DSC, differential scanning calorimeter Q200 manufactured by TA Instruments). After holding the measurement sample at -50 °C for 15 minutes, heat it from -50 °C to 210 °C at a heating rate of 10 °C / minute, measure the first melting peak temperature P (°C), and then hold it at 210 °C for 10 minutes. Then, cool it from 210 °C to -50 °C at a cooling rate of 10 °C / minute and hold it for 15 minutes. Furthermore, heat it from -50 °C to 210 °C at a heating rate of 10 °C / minute and measure the second melting peak temperature Q (°C). In addition, set the nitrogen flow rate to 50 ml / minute. Through the above steps, obtain the first measured melting peak temperature P (°C) and the second measured melting peak temperature Q (°C). Adopt the value of the first measured melting peak temperature P (°C) through the above steps.

[0238] <Measurement of flow amount of colored layer after sealing>

[0239] As the metal terminal, prepare aluminum (JIS H4160:1994 A8079H - O) with a length of 50 mm, a width of 45 mm, and a thickness of 0.4 mm. In addition, cut each adhesive film obtained in the examples and comparative examples into a length of 70 mm and a width of 10 mm. Then, place the adhesive film on the metal terminal to obtain a metal terminal / adhesive film laminate. At this time, laminate it in such a way that the longitudinal and transverse directions of the metal terminal are respectively aligned with the width and length directions of the adhesive film, and the metal terminal is centered with the adhesive film (refer to Figure 10)。In addition, the first layer of the adhesive film is disposed on the side of the metal terminal. Next, with a polytetrafluoroethylene film (PTFE film, thickness 100 μm) placed on the adhesive film of the laminate (covering the surface of the adhesive film with the PTFE film), it is placed on a press heated to 200 °C in the state of silicon wafer / PTFE / this laminate / PTFE / silicone sponge sheet, and at the same time, it is left standing for 16 seconds under the condition of a pressure of 0.25 MPa to thermally bond the adhesive film to the metal terminal. The thermally bonded laminate is naturally cooled to 25 °C. The PTFE is peeled off from the laminate, and the bonding interface in the width direction of the adhesive film (i.e., the longitudinal direction of aluminum) is cut off with a microtome to expose the cross section. The cross section is observed with a laser microscope (VK-9510 manufactured by Keyence Corporation), and the length L of the portion where the colored layer flows out after thermal bonding is measured from the position P at the end of the film before thermal bonding (refer to Figure 11 ), and it is used as the flow amount (μm) of the colored layer after sealing. Observe both sides of the cross section at the center of the length direction of the adhesive film, and adopt the value of the side with the larger flow amount. The results are shown in Table 1.

[0240] <Measurement of the island portion ratio of the sea-island structure of the colored layer>

[0241] The island portion ratio of the sea-island structure of the colored layer of the adhesive film is measured by the following method. The adhesive film is embedded in a thermosetting epoxy resin and cured. Using a commercially available rotary microtome (UC6 manufactured by LEICA) and a diamond knife, a cross section in the target direction (a cross section parallel to TD and in the thickness direction) is made. At this time, by using a cryo-ultramicrotome with liquid nitrogen, the cross section is made at -70 °C. Each embedding resin is stained with ruthenium tetroxide for 12 hours. When staining, polypropylene expands, so the expanded part is trimmed with a microtome and cut from 100 nm in the direction of MD in increments of 300 nm. When a total of about 1 μm to 2 μm is cut, the cross section where the colored layer is exposed is observed as follows. Regarding the stained cross section, it is observed with a field emission scanning electron microscope (S-4800 TYPE1 manufactured by Hitachi High-Technologies Corporation, measurement conditions: 3 kV 20 mA High WD6 mm detector (Upper)) to obtain an image (magnification: 10,000 times). Next, using image processing software (image analysis software WinROOF (Ver7.4) manufactured by Mitani Corporation) that can binarize the image, for this image, the island part and the sea part of the sea-island structure are binarized, and the ratio of the total area of the island part (total area of the island part / area of the measurement range of the image) is obtained. The results are shown in Table 1. In addition, in this measurement, since the island part is stained more than the sea part, the island part looks brighter than the sea part.

[0242] [Image processing conditions]

[0243] Image processing was performed using the image analysis software ImageJ. Specifically, SEM images were obtained in the form of digital files of grayscale images (JPEG), and processed according to the following binarization processing steps and parameters. Pixels with a tone (bright) above the threshold were output as 1, and pixels with a tone (dark) less than the threshold were output as 0, which were respectively defined as island parts and sea parts.

[0244] <Binarization Processing>

[0245] 1. Removal of spike noise (Despeckle)

[0246] 2. Removal of the outline of the island part (Remove Outliers radius=4 threshold=1 which=Bright)

[0247] 3. Removal of the outline of the sea part (Remove Outliers radius=4 threshold=1 which=Dark)

[0248] 4. Removal of spike noise (Despeckle)

[0249] 5. Gaussian blur in the X-axis (short side of the sample) direction (threshold=3 pixels)

[0250] 6. Contrast enhancement (saturated=0.2)

[0251] 7. Removal of the outline of the island part (Remove Outliers radius=4 threshold=1 which=Bright)

[0252] 8. Removal of the outline of the sea part (Remove Outliers radius=4 threshold=1 which=Dark)

[0253] 9. Otsu binarization

[0254] <Measurement of the Ratio of the Soft Segment Component after Heating>

[0255] The adhesive film was heated under the conditions of a temperature of 200 °C, a surface pressure of 0.25 Pa, and 16 seconds. The adhesive film was introduced into a glass sample tube with a diameter of 10 mm. The sample tube was set in a pulsed NMR apparatus (the minispec mq20 manufactured by BRUKER). After maintaining at 40 °C for 5 minutes, a free induction decay curve of 1H spin-spin relaxation was obtained at 40 °C using the solid echo method. The number of scans in the solid echo method was set to 64 times. The obtained decay curve waveform was separated into three curves of three components derived from the hard segment component, the middle segment component, and the soft segment component. The waveform separation used the analysis software "TD-NMRA (Version 4.3 Rev 0.8)" manufactured by BRUKER. The hard segment component was obtained by fitting with a Gaussian function, and the middle segment component and the soft segment component were obtained by fitting with an exponential function. The measurement points up to 0.6 msec of the relaxation curve were used in the analysis. The fitting used the following formula.

[0256] Y = A1 × exp(−(t / τ1) w1 ) + A2 × exp(−(t / τ2) w2 ) + A3 × exp(−(t / τ3) w3 )

[0257] Among them, w1 to w3 are Weber coefficients, w1 takes a value of 2, and w2 and w3 take a value of 1. A1 is the component ratio of the hard segment component, A2 is the component ratio of the middle segment component, A3 is the component ratio of the soft segment component, τ1 represents the relaxation time of the hard segment component, τ2 represents the relaxation time of the middle segment component, τ3 represents the relaxation time of the soft segment component, and t is the time. The component ratios A1, A2, and A3 are the average values obtained by performing the same-level measurement three times.

[0258] <Measurement of water vapor permeability of the adhesive film>

[0259] First, the exterior material for an electrical storage device (hereinafter sometimes simply referred to as "exterior material") is prepared through the following steps. As the base material layer, a biaxially stretched polyethylene terephthalate (PET) film (thickness 12 μm) and a stretched nylon (ONy) film (thickness 15 μm) are prepared. The PET film and the ONy film are bonded using a two-component polyurethane adhesive (a polyol compound and an aromatic isocyanate compound), and an aging treatment is carried out, thereby obtaining a base material layer (thickness 30 μm) formed by laminating a PET film (thickness 12 μm) / adhesive layer (cured thickness 3 μm) / ONy film (thickness 15 μm) in that order from the outside. In addition, as the barrier layer, an aluminum foil (JIS H4160: 1994 A8021H - O (thickness 40 μm)) is prepared. Next, the surface on the ONy film side of the base material layer and the barrier layer are bonded using a two-component polyurethane adhesive (a polyol compound and an aromatic isocyanate compound), and an aging treatment is carried out, thereby obtaining an exterior material for an electrical storage device (total thickness 73 μm) formed by laminating a base material layer (thickness 30 μm) / adhesive layer (cured thickness 3 μm) / barrier layer (thickness 40 μm) in that order.

[0260] Next, as shown in the schematic diagram of Figure 9 , the obtained exterior material 3 is cut into a square with a longitudinal (MD) dimension of 120 mm and a transverse (TD) dimension of 120 mm ( Figure 9 (a)). In addition, two rectangular pieces of the adhesive film 1 cut into a longitudinal (MD) dimension of 120 mm and a transverse (TD) dimension of 10 mm, and two rectangular pieces cut into a longitudinal (MD) dimension of 100 mm and a transverse (TD) dimension of 10 mm are prepared. On the barrier layer side of the exterior material 3, along the periphery of the exterior material 3, adhesive films with the same longitudinal length are arranged opposite each other ( Figure 9 (b)). At this time, the second layer side of the adhesive film is made to be the barrier layer side of the exterior material 3. Next, a polytetrafluoroethylene film (PTFE film, thickness 100 μm) is arranged on the adhesive film of this laminate (covering the surface of the adhesive film with the PTFE film), and it is placed on a press heated to 200 °C in the state of silicon wafer / PTFE / this laminate / PTFE / silicone sponge sheet, and left standing for 16 seconds under the condition of a pressure of 0.25 MPa to thermally bond the adhesive film to the exterior material 3. The thermally bonded laminate is naturally cooled to 25 °C, and the PTFE film is peeled off from the laminate. This heating treatment assumes the physical properties after the adhesive film is arranged between the exterior material for an electrical storage device and the metal terminal and thermally bonded. Next, with the adhesive film on the inside, the exterior material 3 is folded in half longitudinally ( Figure 9(c)). Two adhesive films for metal terminals with a longitudinal (MD) length of 120 mm are arranged in overlap between the outer packaging materials 3 along the long side to be heat-sealed as described below, and two adhesive films for metal terminals with a longitudinal (MD) length of 100 mm are arranged in a folded manner between the outer packaging materials 3 along the short side to be heat-sealed as described below. The peripheral part of the outer packaging material 3 becomes a laminate formed by laminating the outer packaging material / adhesive film / adhesive film / outer packaging material in sequence ( Figure 9 (c)).

[0261] Next, using a heat-sealing bar (stainless steel plate), at the positions of the long side and the short side of the laminate, the layers of the laminate are heat-sealed together by melting to form a bag shape with one short side not heat-sealed ( Figure 9 (c)). The heat-sealing conditions are as follows: for the long side, a heat-sealing bar with a width of 7 mm is used, and heat-sealing is performed once under the conditions of a temperature of 190 °C, a surface pressure of 0.5 MPa, and a time of 1.5 seconds ( Figure 9 (c) s1). In addition, for the short side, a heat-sealing bar with a width of 7 mm is used, and heat-sealing is performed once under the conditions of a temperature of 190 °C, a surface pressure of 0.5 MPa, and a time of 1.5 seconds ( Figure 9 (c) s2). It is dried in a drying chamber for 1 day. Next, from the position of the short side that is not heat-sealed, about 3.0 g of a liquid of ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1:1:1 (volume ratio) (moisture content 0%) is injected ( Figure 9 (d)), and for the short side that is not heat-sealed, heat-sealing is also performed in the same manner as the above-mentioned short side ( Figure 9 (e) s3) to form a sealed bag ( Figure 9 (e)). After leaving this sealed bag standing in an environment of a temperature of 65 °C and a relative humidity of 90% for 30 days, in a drying chamber, the moisture content of the liquid taken out from the sealed bag is measured by the Karl Fischer method to obtain the moisture content (ppm). From the obtained moisture content, the amount of the electrolyte solution input (g), the permeation distance (mm), the permeation cross-sectional area (m 2 ), and the number of storage days (days) are calculated to obtain the water vapor permeability (g·mm / (m 2 ·day)).

[0262] Water vapor permeability (g·mm / (m 2 ·day)) = [the obtained moisture content (ppm) × the input electrolyte solution (g) × the permeation distance (mm)] / [the permeation cross-sectional area (m 2 ) × the number of storage days (days)]

[0263] · The obtained moisture content (ppm): Obtained by the Karl Fischer method.

[0264] · The input electrolyte solution (g): 3.0 g

[0265] · The permeation distance (mm): The width of the sealed part is 7 mm

[0266] · Through-sectional area (m 2 ): Residual thickness (μm) × Inner circumference of the sealing part (mm)

[0267] · Number of storage days (days): 30 days

[0268] <Measurement of the thermal shrinkage rate of the adhesive film>

[0269] Cut the adhesive film into a size of 120 mm (MD) × 120 mm (TD) in length as a test piece. Then, measure the length M (mm) of the test piece with a metal ruler. Next, fix the end of the test piece in the MD direction to a metal mesh with tape so that the test piece hangs down from the metal mesh. In this state, place it in an oven heated to 175 °C for 30 minutes, then take out the test piece together with the metal mesh and let it cool naturally in a room temperature (25 °C) environment. Then, measure the length N (mm) of the test piece that has been naturally cooled to room temperature with a metal ruler. Calculate the thermal shrinkage rate of the adhesive film for the metal terminal by the following formula, and take the average value of n3 as the measurement result. The results are shown in Table 1.

[0270] Thermal shrinkage rate (%) = (Length N / Length M) × 100

[0271] [Table 1]

[0272]

[0273] As described above, the present invention provides an invention in the following-described manner.

[0274] Item 1. An adhesive film for a metal terminal, which is present between a metal terminal electrically connected to an electrode of an electrical storage device element and an outer package material for the electrical storage device that packages the electrical storage device element, wherein

[0275] The adhesive film for the metal terminal is composed of a laminate including at least a first layer disposed on the side of the outer package material for the electrical storage device, a coloring layer, and a second layer disposed on the side of the metal terminal in this order,

[0276] The thickness of the coloring layer is 50 μm or less.

[0277] Item 2. The adhesive film for a metal terminal according to Item 1, wherein the softening point of the coloring layer is higher than the softening point of the second layer.

[0278] Item 3. The adhesive film for a metal terminal according to Item 1 or 2, wherein a sea-island structure is observed in a cross-sectional image obtained by a scanning electron microscope for a cross-section in the direction parallel to TD and in the thickness direction of the coloring layer,

[0279] The island portion ratio of the above-mentioned sea-island structure of the above-mentioned coloring layer is 30% or less.

[0280] Item 4. The adhesive film for metal terminals according to any one of Items 1 to 3, wherein the melting peak temperature of the above-mentioned coloring layer is 135°C or higher.

[0281] Item 5. The adhesive film for metal terminals according to any one of Items 1 to 4, wherein after heating the above-mentioned adhesive film for metal terminals under the conditions of a temperature of 200°C, a surface pressure of 0.25 MPa, and 16 seconds, in an environment of a temperature of 40°C, the ratio of the soft segment component measured by the solid echo method of pulsed NMR of the above-mentioned adhesive film is 20% or less.

[0282] Item 6. The adhesive film for metal terminals according to any one of Items 1 to 5, wherein the above-mentioned coloring layer contains a coloring pigment.

[0283] Item 7. The adhesive film for metal terminals according to any one of Items 1 to 6, wherein the above-mentioned coloring layer is black, gray, or white.

[0284] Item 8. The adhesive film for metal terminals according to any one of Items 1 to 7, wherein the ratio of the thickness of the above-mentioned coloring layer to the thickness of the above-mentioned adhesive film for metal terminals is 0.30 or less.

[0285] Item 9. The adhesive film for metal terminals according to any one of Items 1 to 8, which includes a substrate.

[0286] Item 10. The adhesive film for metal terminals according to any one of Items 1 to 9, wherein the water vapor transmission degree of the above-mentioned adhesive film for metal terminals is 4.20 g·mm / (m 2 ·day) or less.

[0287] Item 11. A method for manufacturing an adhesive film for metal terminals, wherein the above-mentioned adhesive film for metal terminals is present between a metal terminal electrically connected to an electrode of an electrical storage device element and an exterior material for an electrical storage device that encapsulates the above-mentioned electrical storage device element,

[0288] The above-mentioned adhesive film for metal terminals is composed of a laminate including at least a first layer disposed on the side of the exterior material for the electrical storage device, a coloring layer, and a second layer disposed on the side of the metal terminal in sequence.

[0289] The thickness of the above-mentioned coloring layer is 50 μm or less.

[0290] Item 12. A metal terminal with an adhesive film for metal terminals, which is formed by mounting the adhesive film for metal terminals according to any one of Items 1 to 10 on a metal terminal.

[0291] Item 13. A storage device, comprising: a storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an outer packaging material for the storage device that encapsulates the storage device element; and the metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the outer packaging material for the storage device.

[0292] Between the metal terminal and the outer packaging material for the storage device, there is an adhesive film for the metal terminal described in any one of Items 1 to 10.

[0293] Item 14. A method for manufacturing a storage device, the storage device comprising: a storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an outer packaging material for the storage device that encapsulates the storage device element; and the metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the outer packaging material for the storage device.

[0294] The method for manufacturing the storage device includes:

[0295] A step of making an adhesive film for the metal terminal described in any one of Items 1 to 10 exist between the metal terminal and the outer packaging material for the storage device, and encapsulating the storage device element with the outer packaging material for the storage device.

[0296] Item 15. An outer packaging material for a storage device for a storage device, the storage device comprising: a storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an outer packaging material for the storage device that encapsulates the storage device element; and the metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the outer packaging material for the storage device. Between the metal terminal and the outer packaging material for the storage device, there is an adhesive film for the metal terminal.

[0297] The adhesive film for the metal terminal is the adhesive film for the metal terminal described in any one of Items 1 to 10.

[0298] The outer packaging material for the storage device is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealable resin layer.

[0299] Item 16. A kit, comprising: an outer packaging material for a storage device for a storage device, and an adhesive film for the metal terminal described in any one of Items 1 to 10.

[0300] The storage device includes: a storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an outer packaging material for the storage device that encapsulates the storage device element; and the metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the outer packaging material for the storage device.

[0301] In use, it is used in such a manner that the adhesive film for metal terminals is present between the metal terminals and the exterior material for the electrical storage device.

[0302] Explanation of symbols

[0303] 1 Adhesive film for metal terminals

[0304] 2 Metal terminals

[0305] 3 Exterior material for electrical storage device

[0306] 3a Peripheral portion of the exterior material for electrical storage device

[0307] 4 Electrical storage device element

[0308] 10 Electrical storage device

[0309] 11 Coloring layer

[0310] 12a First layer

[0311] 12b Second layer

[0312] 12c Third layer

[0313] 12d Fourth layer

[0314] 14 Base material

[0315] 31 Base material layer

[0316] 32 Adhesive layer

[0317] 33 Barrier layer

[0318] 34 Bonding layer

[0319] 35 Heat-sealable resin layer.

Claims

1. An adhesive film for a metal terminal, which is present between a metal terminal electrically connected to an electrode of an electrical storage device element and an exterior material for an electrical storage device that encapsulates the electrical storage device element, wherein the adhesive film for a metal terminal is characterized in that: The adhesive film for a metal terminal is composed of a laminate including at least a first layer disposed on the side of the exterior material for an electrical storage device, a coloring layer, and a second layer disposed on the side of the metal terminal in this order. The thickness of the coloring layer is 50 μm or less.

2. The adhesive film for a metal terminal according to claim 1, wherein: The softening point of the coloring layer is higher than the softening point of the second layer.

3. The adhesive film for a metal terminal according to claim 1 or 2, wherein: In a cross-sectional image obtained by a scanning electron microscope of a cross-section in the direction parallel to TD and in the thickness direction of the coloring layer, a sea-island structure is observed. The island portion ratio of the sea-island structure of the coloring layer is 30% or less.

4. The adhesive film for a metal terminal according to claim 1 or 2, wherein: The melting peak temperature of the coloring layer is 135°C or higher.

5. The adhesive film for a metal terminal according to claim 1 or 2, wherein: After the adhesive film for a metal terminal is heated under the conditions of a temperature of 200°C, a surface pressure of 0.25 MPa, and 16 seconds, in an environment of a temperature of 40°C, the ratio of the soft segment component measured by the solid echo method using pulsed NMR of the adhesive film is 20% or less.

6. The adhesive film for a metal terminal according to claim 1 or 2, wherein: The coloring layer contains a coloring pigment.

7. The adhesive film for a metal terminal according to claim 1 or 2, wherein: The coloring layer is black, gray, or white.

8. The adhesive film for a metal terminal according to claim 1 or 2, wherein: The ratio of the thickness of the coloring layer to the thickness of the adhesive film for a metal terminal is 0.30 or less.

9. The adhesive film for a metal terminal according to claim 1 or 2, wherein: It includes a substrate.

10. The adhesive film for a metal terminal according to claim 1 or 2, wherein: The water vapor transmission rate of the adhesive film for the metal terminal is 5.10 g·mm / (m 2 ·day) or less.

11. A method for manufacturing an adhesive film for a metal terminal, the adhesive film for a metal terminal being present between a metal terminal electrically connected to an electrode of an electrical storage device element and an exterior material for an electrical storage device that encapsulates the electrical storage device element, wherein the method for manufacturing the adhesive film for a metal terminal is characterized in that: The adhesive film for a metal terminal is composed of a laminate including at least a first layer disposed on the side of the exterior material for an electrical storage device, a coloring layer, and a second layer disposed on the side of the metal terminal in this order. The thickness of the coloring layer is 50 μm or less.

12. A metal terminal with an adhesive film for a metal terminal, wherein: It is formed by mounting the adhesive film for a metal terminal according to claim 1 or 2 on a metal terminal.

13. An electrical storage device, wherein: It includes: An electrical storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an exterior material for an electrical storage device that encapsulates the electrical storage device element; and the metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the exterior material for the electrical storage device Between the metal terminal and the exterior material for the electrical storage device, there is the adhesive film for the metal terminal according to claim 1 or 2.

14. A method for manufacturing an electrical storage device, characterized in that: The electrical storage device includes: an electrical storage device element having at least a positive electrode, a negative electrode, and an electrolyte; the exterior material for the electrical storage device that encapsulates the electrical storage device element; and the metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the exterior material for the electrical storage device The method for manufacturing the electrical storage device includes: A step of disposing the adhesive film for the metal terminal according to claim 1 or 2 between the metal terminal and the exterior material for the electrical storage device, and encapsulating the electrical storage device element with the exterior material for the electrical storage device.

15. An exterior material for an electrical storage device for an electrical storage device, characterized in that: The electrical storage device includes: an electrical storage device element having at least a positive electrode, a negative electrode, and an electrolyte; the exterior material for the electrical storage device that encapsulates the electrical storage device element; and the metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the exterior material for the electrical storage device, and between the metal terminal and the exterior material for the electrical storage device, there is an adhesive film for the metal terminal The adhesive film for the metal terminal is the adhesive film for the metal terminal according to claim 1 or 2, The exterior material for the electrical storage device is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealable resin layer.

16. A kit, characterized in that: The kit includes an exterior material for an electrical storage device for an electrical storage device and the adhesive film for the metal terminal according to claim 1 or 2, The electrical storage device includes: an electrical storage device element having at least a positive electrode, a negative electrode, and an electrolyte; the exterior material for the electrical storage device that encapsulates the electrical storage device element; and the metal terminals that are electrically connected to the positive electrode and the negative electrode respectively and protrude to the outside of the exterior material for the electrical storage device When in use, it is used in such a manner that the adhesive film for the metal terminal is present between the metal terminal and the exterior material for the electrical storage device.

Images