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

Abstract

To provide an adhesive film for a metal terminal that exhibits high sealing strength when bonded to an exterior material for a power storage device, and a method for manufacturing the same.SOLUTION: An adhesive film 1 for a metal terminal is composed of a laminate having, in this order, a first polyolefin layer arranged on the surface of an exterior material 3 for a power storage device, a substrate, and a second polyolefin layer arranged on the metal terminal 2 side, the tensile modulus of the adhesive film for metal terminals is 700 MPa or less, the substrate is the layer located between the first polyolefin layer and the second polyolefin layer that has the highest Martens hardness measured perpendicular to the cross section in the thickness direction of the layer, and the absolute value of the difference between the Martens hardness measured perpendicular to the cross section in the thickness direction of the substrate and the Martens hardness measured perpendicular to the cross section in the thickness direction of the first polyolefin layer is 10 N / mm2 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

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

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

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

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

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-79638 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, as the capacity of electricity storage devices has increased, the amount of gas generated from electricity storage device elements has tended to increase. When the internal pressure of the electricity storage device increases due to gas generation from the electricity storage device elements, there is a problem that the adhesive film for metal terminals bonded to the exterior material for electricity storage devices becomes more likely to peel off.

[0008] A primary object of the present disclosure is to provide an adhesive film for metal terminals that is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that encapsulates the electricity storage device element, the adhesive film for metal terminals exhibiting high sealing strength with the exterior material for an electricity storage device. Further objects of the present disclosure include providing a method for manufacturing the adhesive film for metal terminals, a metal terminal with an adhesive film for metal terminals, an exterior material for an electricity storage device, a kit including an exterior material for an electricity storage device and the adhesive film for metal terminals, an electricity storage device, and a method for manufacturing the electricity storage device. [Means for solving the problem]

[0009] The inventors of the present disclosure have conducted extensive research to solve the above-mentioned problems, and as a result, when an adhesive film for metal terminals is composed of a laminate including, in this order, at least a first polyolefin layer disposed on the surface of the exterior material for an electricity storage device, a substrate, and a second polyolefin layer disposed on the metal terminal side, and the tensile modulus of the adhesive film for metal terminals is set to 700 MPa or less, and further, when the layer located between the first polyolefin layer and the second polyolefin layer and having the highest Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the layer is used as the substrate, the absolute value of the difference between the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the substrate and the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the first polyolefin layer is 10 N / mm 2 It has been found that by setting the following, a high sealing strength can be achieved between the adhesive film for a metal terminal and the exterior material for an electricity storage device. The present disclosure has been completed through further investigation based on this finding.

[0010] That is, the present disclosure provides the inventions of the following aspects. An adhesive film for metal terminals, which is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element, the adhesive film for metal terminal is composed of a laminate including, in this order, at least a first polyolefin layer disposed on the surface of the exterior material for the electricity storage device, a base material, and a second polyolefin layer disposed on the metal terminal side; The adhesive film for metal terminal has a tensile modulus of 700 MPa or less, the substrate is a layer located between the first polyolefin layer and the second polyolefin layer, and has the highest Martens hardness measured in a direction perpendicular to a cross section in the thickness direction of the layer; The absolute value of the difference between the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the substrate and the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the first polyolefin layer is 10 N / mm 2 The adhesive film for metal terminals is as follows: [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide an adhesive film for metal terminals that is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that encapsulates the electricity storage device element, the adhesive film for metal terminals exhibiting high sealing strength with the exterior material for an electricity storage device.Furthermore, it is an object of the present disclosure to provide a method for manufacturing the adhesive film for metal terminals, a metal terminal with an adhesive film for metal terminals, an exterior material for an electricity storage device, a kit including an exterior material for an electricity storage device and an adhesive film for metal terminals, and an electricity storage device and a method for manufacturing the same. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic plan view of an electricity storage device according to the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along line AA' in FIG. [Figure 3] FIG. 2 is a schematic cross-sectional view taken along line BB' in FIG. [Figure 4] 1 is a schematic cross-sectional view of an adhesive film for metal terminals according to the present disclosure. [Figure 5]1 is a schematic cross-sectional view of an adhesive film for metal terminals according to the present disclosure. [Figure 6] 1 is a schematic cross-sectional view of an adhesive film for metal terminals according to the present disclosure. [Figure 7] 1 is a schematic cross-sectional view of an adhesive film for metal terminals according to the present disclosure. [Figure 8] 1 is a schematic cross-sectional view of an exterior packaging material for an electricity storage device according to the present disclosure. [Figure 9] FIG. 2 is a schematic diagram illustrating a method for measuring the seal strength (adhesion strength) between an adhesive film and an exterior material. [Figure 10] FIG. 2 is a schematic diagram illustrating a method for measuring the seal strength (adhesion strength) between an adhesive film and an exterior material. DETAILED DESCRIPTION OF THE INVENTION

[0013] The adhesive film for metal terminal of the present disclosure is an adhesive film for metal terminal interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element. The adhesive film for metal terminal of the present disclosure is composed of a laminate including, in this order, at least a first polyolefin layer disposed on the surface of the exterior material for an electricity storage device, a substrate, and a second polyolefin layer disposed on the metal terminal side. The adhesive film for metal terminal has a tensile modulus of 700 MPa or less. The substrate is the layer between the first polyolefin layer and the second polyolefin layer that has the highest Martens hardness measured in a direction perpendicular to a cross section in the thickness direction of the layer. In the adhesive film for metal terminal of the present disclosure, the absolute value of the difference between the Martens hardness measured in a direction perpendicular to a cross section in the thickness direction of the substrate and the Martens hardness measured in a direction perpendicular to a cross section in the thickness direction of the first polyolefin layer is 10 N / mm 2 The following is the result.

[0014] Because the adhesive film for a metal terminal of the present disclosure has these characteristics, it can exhibit high sealing strength with an electrical storage device packaging material. More specifically, the adhesive film for a metal terminal of the present disclosure is interposed between a metal terminal electrically connected to an electrode of an electrical storage device element and an electrical storage device packaging material that encapsulates the electrical storage device element, and can exhibit high sealing strength with the heat-sealable resin layer of the electrical storage device packaging material.

[0015] The electricity storage device of the present disclosure is also an electricity storage device comprising at least an electricity storage device element having a positive electrode, a negative electrode, and an electrolyte, an exterior material for an electricity storage device that seals the electricity storage device element, and metal terminals that are electrically connected to the positive electrode and the negative electrode, respectively, and protrude outside the exterior material for an electricity storage device, and is characterized in that an adhesive film for metal terminals of the present disclosure is interposed between the metal terminals and the exterior material for an electricity storage device.

[0016] The adhesive film for metal terminal and its manufacturing method, and the electricity storage device and its manufacturing method according to the present disclosure will be described in detail below.

[0017] In this specification, when referring to a numerical range, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the notation "2 to 15 mm" means 2 mm or greater and 15 mm or less. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, separately described upper and lower limits, upper and lower limits, or lower and lower limits may each be combined to form a numerical range. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0018] Another method for confirming the MD of an adhesive film for metal terminals is to observe a cross section of the adhesive film for metal terminals (e.g., a cross section of an acid-modified polyolefin layer or a polyolefin layer) using an electron microscope to confirm the sea-island structure. In this method, the direction parallel to the cross section in which the average diameter of the island shapes in the direction perpendicular to the thickness direction of the adhesive film for metal terminals is the largest can be determined as the MD. Specifically, the sea-island structure is confirmed by observing, using an electron microscope, a cross section of the adhesive film for metal terminals in the longitudinal direction and each cross section at an angle of 10 degrees from the direction parallel to the cross section in the longitudinal direction up to the direction perpendicular to the cross section in the longitudinal direction (a total of 10 cross sections). Next, the shape of each individual island is observed in each cross section. For each island shape, the linear distance connecting the leftmost end in the direction perpendicular to the thickness direction of the adhesive film for metal terminals to the rightmost end in the vertical direction is defined as the diameter y. For each cross section, the average of the diameters y of the top 20 island shapes in order of largest diameter y is calculated. The direction parallel to the cross section in which the average diameter y of the island shape is the largest is determined to be the MD. Alternatively, for example, the adhesive film for metal terminals can be left in an environment of 150°C for 2 minutes, and the thermal shrinkage rate measured, and the direction with the larger shrinkage rate determined to be the MD.

[0019] 1. Adhesive film for metal terminals The adhesive film for a metal terminal of the present disclosure is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element. Specifically, as shown in Figures 1 to 3, for example, an adhesive film for a metal terminal 1 of the present disclosure is interposed between a metal terminal 2 electrically connected to an electrode of an electricity storage device element 4 and an exterior material for an electricity storage device 3 that seals the electricity storage device element 4. The metal terminal 2 protrudes outside the exterior material for an electricity storage device 3, and is sandwiched between the exterior material for an electricity storage device 3, via the adhesive film for a metal terminal 1, at a peripheral portion 3a of the heat-sealed exterior material for an electricity storage device 3.

[0020] In the present disclosure, the temporary bonding step of the adhesive film for metal terminal to the metal terminal is carried out, for example, at a temperature of about 140 to 160°C, under a pressure of about 0.01 to 1.0 MPa, for about 3 to 15 seconds, and about 3 to 6 cycles, while the main bonding step is carried out, for example, at a temperature of about 160 to 240°C, under a pressure of about 0.01 to 1.0 MPa, for about 3 to 15 seconds, and about 1 to 3 cycles. Furthermore, when the metal terminal with the adhesive film for metal terminal is interposed between the exterior material for an electricity storage device and heat-sealed, the heating temperature is typically in the range of about 180 to 210°C, and the pressure is typically about 1.0 to 5.0 MPa, for about 1 to 5 seconds, and about 1 cycle.

[0021] The adhesive film 1 for metal terminals (hereinafter, sometimes simply referred to as "adhesive film") of the present disclosure is provided to improve adhesion between the metal terminal 2 and the electricity storage device exterior material 3. Improved adhesion between the metal terminal 2 and the electricity storage device exterior material 3 improves the sealing of the electricity storage device element 4. As described above, when the electricity storage device element 4 is heat-sealed, the electricity storage device element is sealed such that the metal terminal 2 electrically connected to the electrode of the electricity storage device element 4 protrudes outside the electricity storage device exterior material 3. At this time, the metal terminal 2 made of metal and the heat-sealable resin layer 35 (a layer made of a heat-sealable resin such as polyolefin) located in the innermost layer of the electricity storage device exterior material 3 are made of different materials. Therefore, without using such an adhesive film, the sealing of the electricity storage device element is likely to be poor at the interface between the metal terminal 2 and the heat-sealable resin layer 35.

[0022] Lamination structure and properties of adhesive films for metal terminals The adhesive film for metal terminal of the present disclosure is composed of a laminate including, in order from the side of the exterior packaging material for an electricity storage device, at least a first polyolefin layer 12a, a substrate 11, and a second polyolefin layer 12b. In the adhesive film for metal terminal 1, the first polyolefin layer 12a forms the surface facing the exterior packaging material for an electricity storage device. In the laminate constituting the adhesive film for metal terminal 1 of the present disclosure, the substrate 11 is used as the reference, and the side of the first polyolefin layer 12a closer to the substrate 11 is the side of the exterior packaging material for an electricity storage device, and the side of the second polyolefin layer 12b closer to the substrate 11 is the side of the metal terminal 2. The adhesive film for metal terminal 1 preferably has a 3- to 6-layer configuration.

[0023] As shown in Fig. 5, the adhesive film 1 for metal terminals may include an adhesion promoter layer 13 between the substrate 11 and the first polyolefin layer 12a and / or between the substrate 11 and the second polyolefin layer 12b. By including the adhesion promoter layer 13, the adhesion between the substrate 11 and the first polyolefin layer 12a and between the substrate 11 and the second polyolefin layer 12b can be further strengthened. Fig. 5 illustrates a laminate structure in which an adhesion promoter layer 13 is provided between the substrate 11 and the first polyolefin layer 12a and between the substrate 11 and the second polyolefin layer 12b. Details of the adhesion promoter layer 13 will be described later.

[0024] Furthermore, the adhesive film 1 for metal terminals may further include one or more resin layers (such as a third layer 12c, a fourth layer 12d, and a fifth layer 12e) in addition to the substrate 11, the first polyolefin layer 12a, and the second polyolefin layer 12b. FIG. 6 illustrates a laminate structure in which the third layer 12c is provided between the substrate 11 and the first polyolefin layer 12a, and the fourth layer 12d is provided between the substrate 11 and the second polyolefin layer 12b. As described above, in the adhesive film 1 for metal terminals of the present disclosure, the first polyolefin layer 12a constitutes the surface facing the exterior material for an electricity storage device, and therefore the resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e are provided between the first polyolefin layer 12a and the substrate 11 and / or closer to the metal terminal 2 than the substrate 11.

[0025] The adhesive film 1 for a metal terminal may also include a colored layer 14 between the first polyolefin layer 12a and the second polyolefin layer 12b, as shown in FIGS. 6 and 7. The colored layer 14 is a resin layer colored with a colorant, and any layer between the first polyolefin layer 12a and the second polyolefin layer 12b may be the colored layer 14. For example, the substrate 11, the adhesion promoter layer 13, or a resin layer (such as the third layer 12c, the fourth layer 12d, or the fifth layer 12e) may be the colored layer 14. FIG. 6 shows an example in which the substrate 11 constitutes the colored layer 14, while FIG. 7 shows an example in which the third layer 12c provided between the substrate 11 and the second polyolefin layer 12b constitutes the colored layer 14. The colored layer 14 included in the adhesive film 1 for a metal terminal may be a single layer or two or more layers.

[0026] Specific examples of the layer structure of the adhesive film for metal terminal 1 are shown below. In the following layer structure, at least one of the substrate 11, the third layer 12c, the fourth layer 12d, the fifth layer 12e, and the adhesion promoter layer 13 may be colored (contain a colorant) to form the colored layer 14. In addition, at least one of the first polyolefin layer 12a and the second polyolefin layer 12b may also be colored (contain a colorant) to form the colored layer 14. A laminated structure in which a first polyolefin layer 12a, a substrate 11, and a second polyolefin layer 12b are laminated in this order. A laminated structure in which the first polyolefin layer 12a, the third layer 12c, the substrate 11, and the second polyolefin layer 12b are laminated in this order. A laminated structure in which the first polyolefin layer 12a, the substrate 11, the third layer 12c, and the second polyolefin layer 12b are laminated in this order. A laminated structure in which the first polyolefin layer 12a, the third layer 12c, the substrate 11, the fourth layer 12d, and the second polyolefin layer 12b are laminated in this order. A laminated structure in which the first polyolefin layer 12a, the third layer 12c, the substrate 11, the second polyolefin layer 12b, and the fourth layer 12d are laminated in this order. A laminated structure in which the first polyolefin layer 12a, the third layer 12c, the fourth layer 12d, the substrate 11, the fifth layer 12e, and the second polyolefin layer 12b are laminated in this order. A laminated structure in which the first polyolefin layer 12a, the third layer 12c, the substrate 11, the fourth layer 12d, the fifth layer 12e, and the second polyolefin layer 12b are laminated in this order. A laminated structure in which the first polyolefin layer 12a, the third layer 12c, the substrate 11, the fourth layer 12d, the second polyolefin layer 12b, and the fifth layer 12e are laminated in this order. A laminated structure in which a first polyolefin layer 12a, an adhesion promoter layer 13, a substrate 11, and a second polyolefin layer 12b are laminated in this order. A laminated structure in which a first polyolefin layer 12a, a substrate 11, an adhesion promoter layer 13, and a second polyolefin layer 12b are laminated in this order. A laminated structure in which a first polyolefin layer 12a, an adhesion promoter layer 13, a substrate 11, an adhesion promoter layer 13, and a second polyolefin layer 12b are laminated in this order.

[0027] The tensile modulus of the adhesive film for metal terminal of the present disclosure is 700 MPa or less. From the viewpoint of more optimally exhibiting the effects of the present disclosure, it is preferably about 650 MPa or less, more preferably about 600 MPa or less, and even more preferably about 550 MPa or less. The lower limit is preferably about 300 MPa or more, more preferably about 350 MPa or more, and even more preferably about 400 MPa or more. Preferred ranges include about 300 to 700 MPa, about 300 to 650 MPa, about 300 to 600 MPa, about 300 to 550 MPa, about 350 to 700 MPa, about 350 to 650 MPa, about 350 to 600 MPa, about 350 to 550 MPa, about 400 to 700 MPa, about 400 to 650 MPa, about 400 to 600 MPa, and about 400 to 550 MPa. The tensile modulus of the adhesive film for metal terminal is measured as follows.

[0028] <Tensile modulus> The tensile modulus of a sample (adhesive film for metal terminals) was measured at 25°C in accordance with JIS K7161-1 (ISO527-1). Specifically, the sample was cut into a strip with a width (TD) of 15 mm and a length (MD) of 50 mm. Next, a stress-strain curve of the sample specimen was obtained using a Tensilon universal testing machine at a tensile speed of 300 mm / min and a chuck distance of 30 mm at 25°C. The tensile modulus of the sample was determined from the slope of the line connecting the two points at 0.05% and 0.25% strain. The tensile modulus of the substrate, colored layer, first polyolefin layer, and second polyolefin layer was measured using each layer as a separate sample. The measurement was performed three times, and the average value (N=3) was used. If a 15mm wide (TD) sample could not be prepared, the tensile modulus was measured in the same manner for samples of different widths.

[0029] Furthermore, the adhesive film for metal terminal 1 has an absolute value of the difference between the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the substrate 11 and the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the first polyolefin layer 12a of 10 N / mm 2 From the viewpoint of more suitably exerting the effects of the present disclosure, the absolute value of the difference from the Martens hardness is preferably about 9 N / mm 2 Less than or equal to about 8 N / mm 2 or less, more preferably about 5 N / mm 2 or less, more preferably about 3 N / mm 2 The lower limit is, for example, about 0 N / mm 2 The preferable range is 0 to 10 N / mm 2 Degree, 0~9N / mm 2 Degree, 0~8N / mm 2 Degree, 0~5N / mm 2 Degree, 0~3N / mm 2 The degree of

[0030] From the viewpoint of more suitably exerting the effects of the present disclosure, the absolute value of the difference between the tensile modulus of the substrate 11 and the tensile modulus of the first polyolefin layer 12a in the adhesive film for metal terminal 1 is preferably about 400 MPa or less, more preferably about 350 MPa or less, even more preferably about 300 MPa or less, even more preferably about 200 MPa or less, and even more preferably about 100 MPa or less, and the lower limit is about 0 MPa or more, with preferred ranges being about 0 to 400 MPa, about 0 to 350 MPa, about 0 to 300 MPa, about 0 to 200 MPa, and about 0 to 100 MPa. The tensile modulus of the substrate 11 is a value measured using the substrate 11 as a sample in the measurement of the tensile modulus described above in <Tensile Modulus>.

[0031] Furthermore, from the viewpoint of more suitably exerting the effects of the present disclosure, it is preferable that the tensile modulus value of the second polyolefin layer 12b of the adhesive film for metal terminal 1 is equal to or less than the tensile modulus value of the substrate 11. The tensile modulus of the second polyolefin layer 12b is a value measured using the second polyolefin layer 12b as a sample in the measurement of the tensile modulus described above in <Tensile Modulus>.

[0032] Furthermore, from the viewpoint of more suitably exerting the effects of the present disclosure, in the adhesive film for metal terminal 1, the absolute value of the difference between the tensile modulus of the first polyolefin layer 12a and the tensile modulus of the substrate 11 is preferably 300 MPa or less, the absolute value of the difference between the tensile modulus of the second polyolefin layer 12b and the tensile modulus of the substrate 11 is preferably 300 MPa or less, and the absolute value of the difference between the tensile modulus of the first polyolefin layer 12a and the tensile modulus of the second polyolefin layer 12b is preferably 300 MPa or less. The absolute value of the difference between the tensile modulus of the first polyolefin layer 12a and the tensile modulus of the substrate 11 is more preferably about 250 MPa or less, even more preferably about 200 MPa or less, and is preferably about 0 MPa or more, with preferred ranges being about 0 to 300 MPa, about 0 to 250 MPa, and about 0 to 200 MPa. The absolute value of the difference between the tensile modulus of the second polyolefin layer 12b and the tensile modulus of the substrate 11 is more preferably about 250 MPa or less, even more preferably about 200 MPa or less, and is preferably about 0 MPa or more, more preferably about 5 MPa or more, and even more preferably about 10 MPa or more, with preferred ranges being about 0 to 300 MPa, 0 to 250 MPa, 0 to 200 MPa, 5 to 300 MPa, 5 to 250 MPa, 5 to 200 MPa, 10 to 300 MPa, 10 to 250 MPa, and 10 to 200 MPa. The absolute value of the difference between the tensile modulus of the first polyolefin layer 12a and the tensile modulus of the second polyolefin layer 12b is more preferably about 250 MPa or less, even more preferably about 200 MPa or less, with the lower limit being about 0 MPa or more, and preferred ranges being about 0 to 300 MPa, 0 to 250 MPa, and 0 to 200 MPa. The tensile modulus of the first polyolefin layer 12a is a value measured using the first polyolefin layer 12a as a sample in the measurement of the tensile modulus described above in <Tensile modulus>.

[0033] <Martens hardness> In the present disclosure, the Martens hardness of each layer (e.g., the substrate 11, the first polyolefin layer 12a, the second polyolefin layer 12b, the colored layer 14, etc.) of the adhesive film for metal terminal 1 is measured as follows. The Martens hardness of each layer is measured by using the adhesive film for metal terminal 1 as a sample and measuring each layer laminated on the sample. Specifically, the sample to be measured is pretreated by cutting the adhesive film for metal terminal 1 to 30 mm in MD and 15 mm in TD. Next, the sample is embedded in epoxy cold mounting resin and allowed to dry for about one day. After that, a mechanical polishing device is used to polish the embedded sample in a direction parallel to the TD direction, so that the cross section of the sample has a surface roughness of about 1.0 μm. To measure Martens hardness using the indentation method, the Martens hardness is measured in a direction perpendicular to the cross section in the thickness direction of the layer to be measured (the center part in the thickness direction).

[0034] [Martens hardness measurement conditions] The applied load was 25 mN. The load application rate was 25 mN / 20 seconds. The holding time was 5 seconds. The load unloading rate was 25 mN / 20 seconds. The indenter was a Vickers indenter with a square pyramid tip with a facing angle of 136°. The measurement temperature was 25°C. Measurements were taken 10 times at different measurement locations, and the measurement value was the average of a total of eight measurement values, excluding one maximum and one minimum value.

[0035] From the viewpoint of more suitably achieving the effects of the present disclosure, the total thickness of the adhesive film 1 for a metal terminal is, for example, about 50 μm or more, preferably about 80 μm or more, more preferably about 90 μm or more, and even more preferably about 100 μm or more. The total thickness of the adhesive film 1 for a metal terminal of the present disclosure is about 500 μm or less, preferably about 300 μm or less, more preferably about 250 μm or less, and even more preferably about 200 μm or less. Preferred ranges for the total thickness of the adhesive film 1 for metal terminals of the present disclosure include approximately 50 to 500 μm, approximately 50 to 300 μm, approximately 50 to 250 μm, approximately 50 to 200 μm, approximately 80 to 500 μm, approximately 80 to 300 μm, approximately 80 to 250 μm, approximately 80 to 200 μm, approximately 90 to 500 μm, approximately 90 to 300 μm, approximately 90 to 250 μm, approximately 90 to 200 μm, approximately 100 to 500 μm, approximately 100 to 300 μm, approximately 100 to 250 μm, and approximately 100 to 200 μm. As a more specific example, when the adhesive film 1 for metal terminals of the present disclosure is used in a relatively small power storage device for a mobile phone, smartphone, or tablet, the total thickness is preferably about 60 to 100 μm, and when it is used in a relatively large power storage device for a power storage system or an in-vehicle power storage device, the total thickness is preferably about 100 to 300 μm.

[0036] In the adhesive film 1 for metal terminals, the ratio of the total thickness of the first polyolefin layer 12a, the substrate 11, the second polyolefin layer 12b, the optional adhesion promoter layer 13, and the optional resin layers (such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e) to the thickness (total thickness) of the laminate constituting the adhesive film 1 for metal terminals is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the adhesive film 1 for metal terminals of the present disclosure includes the first polyolefin layer 12a, the substrate 11, and the second polyolefin layer 12b, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the adhesive film for metal terminals 1 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, when the adhesive film 1 for metal terminal of the present disclosure comprises the first polyolefin layer 12a, the substrate 11, the second polyolefin layer 12b, and the third layer 12c, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the adhesive film for metal terminal 1 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, when the adhesive film 1 for metal terminal of the present disclosure comprises the first polyolefin layer 12a, the substrate 11, the second polyolefin layer 12b, the third layer 12c, and the fourth layer 12d, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the adhesive film for metal terminal 1 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, when the adhesive film 1 for metal terminals of the present disclosure includes a first polyolefin layer 12a, a substrate 11, a second polyolefin layer 12b, a third layer 12c, a fourth layer 12d, and a fifth layer 12e, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the adhesive film for metal terminals 1 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0037] Each layer that forms the adhesive film for metal terminals [Base material 11] In the adhesive film for metal terminal 1, the substrate 11 is provided between the first polyolefin layer 12a and the second polyolefin layer 12b, and is a layer that functions as a support for the adhesive film for metal terminal 1. As described below, the substrate 11 can also be colored to form a colored layer 14 described below.

[0038] The substrate 11 can be formed, for example, from a resin film. When the substrate 11 is formed from a resin film, a pre-formed resin film may be used as the substrate 11 when the adhesive film for a metal terminal 1 of the present disclosure is produced by laminating the substrate 11 with the first polyolefin layer 12a, the second polyolefin layer 12b, etc. Alternatively, the resin forming the substrate 11 may be formed into a film on the surface of the first polyolefin layer 12a, the second polyolefin layer 12b, etc. by extrusion molding, coating, etc., to form the substrate 11 formed from a resin film.

[0039] The material forming the substrate 11 is not particularly limited. Examples of materials that can be used to form the substrate 11 include polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicone resins, phenolic resins, polyetherimides, polyimides, polycarbonates, and mixtures or copolymers thereof. Among these, polyolefin resins are particularly preferred. That is, the material forming the substrate 11 is preferably a resin containing a polyolefin skeleton, such as polyolefin or acid-modified polyolefin. Whether the resin constituting the substrate 11 contains a polyolefin skeleton can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like.

[0040] The substrate 11 preferably contains a polyolefin resin, preferably contains a polyolefin, and is more preferably a layer formed of a polyolefin. The polyolefin layer may be a stretched polyolefin film or an unstretched polyolefin film, but is preferably an unstretched polyolefin film. Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, polypropylene block copolymers (e.g., propylene-ethylene block copolymers), and polypropylene random copolymers (e.g., propylene-ethylene random copolymers); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred, and polypropylene is more preferred. Furthermore, due to its excellent electrolyte resistance, the substrate 11 preferably contains homopolypropylene, is more preferably formed of homopolypropylene, and is even more preferably an unstretched homopolypropylene film.

[0041] Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (where I represents isophthalic acid and T represents terephthalic acid) containing structural units derived from terephthalic acid and / or isophthalic acid; aromatic polyamides such as polymetaxylylene adipamide (MXD6); alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); polyamides copolymerized with lactam components or isocyanate components such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers, which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and copolymers thereof. These polyamides may be used alone or in combination of two or more.

[0042] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymer polyesters whose repeating units are mainly ethylene terephthalate, copolymer polyesters whose repeating units are mainly butylene terephthalate, etc. Specific examples of copolymer polyesters whose repeating units are mainly ethylene terephthalate include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decanedicarboxylate), etc. Specific examples of copolymer polyesters containing butylene terephthalate as the main repeating unit include copolymer polyesters in which butylene terephthalate is the main repeating unit and is polymerized with butylene isophthalate (hereinafter abbreviated as polybutylene (terephthalate / isophthalate)), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate, etc. These polyesters may be used alone or in combination of two or more.

[0043] Methods for adjusting the Martens hardness and tensile modulus include the resin material and resin composition selected, the cooling conditions during film formation (the time it takes for the resin extruded from the die to cool to room temperature), and the resin formation method (extrusion method, inflation method, etc.).

[0044] Of the layers located between the first polyolefin layer 12a and the second polyolefin layer 12b, the substrate 11 is the layer having the highest Martens hardness measured in a direction perpendicular to a cross section in the thickness direction of the layer.

[0045] The Martens hardness of the substrate 11 is such that the absolute value of the difference between the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the substrate 11 and the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the first polyolefin layer 12a is 10 N / mm 2 From the viewpoint of more suitably exhibiting the effects of the present disclosure, the Martens hardness of the substrate 11 is preferably about 10 N / mm 2 More preferably, about 15 N / mm 2 More preferably, about 20 N / mm 2 or more, and preferably about 40 N / mm 2 or less, more preferably about 35 N / mm 2 or less, more preferably about 30 N / mm 2 The preferred range is 10 to 40 N / mm 2 Degree, 10~35N / mm 2 Degree, 10~30N / mm 2 degree, 15~40N / mm 2 Degree, 15~35N / mm 2 degree, 15~30N / mm 2 Degree, 20~40N / mm 2 Degree, 20~35N / mm 2 degree, 20~30N / mm 2 The degree of

[0046] Furthermore, the tensile modulus of the substrate 11 is not particularly limited, as long as the tensile modulus of the adhesive film for metal terminal 1 is 700 MPa or less. From the viewpoint of more suitably exhibiting the effects of the present disclosure, the tensile modulus of the substrate 11 is preferably 820 MPa or less, more preferably 800 MPa or less, even more preferably 750 MPa or less, and even more preferably 600 MPa or less, and is also preferably 250 MPa or more, more preferably 300 MPa or more, and even more preferably 350 MPa or more, and preferred ranges include about 250 to 820 MPa, about 250 to 800 MPa, about 250 to 750 MPa, about 250 to 600 MPa, about 300 to 820 MPa, about 300 to 800 MPa, about 300 to 750 MPa, about 300 to 600 MPa, about 350 to 820 MPa, about 350 to 800 MPa, about 350 to 750 MPa, and about 350 to 600 MPa.

[0047] The melting peak temperature of the substrate 11 is preferably 120° C. or higher, more preferably about 130° C. or higher, and even more preferably about 140° C. or higher. From the same viewpoint, the melting peak temperature is, for example, about 210° C. or lower, preferably about 200° C. or lower, more preferably about 190° C. or lower, even more preferably about 180° C. or lower, and even more preferably about 170° C. or lower. Preferred ranges of the melting peak temperature include about 120 to 210° C., about 120 to 200° C., about 120 to 190° C., about 120 to 180° C., about 120 to 170° C., about 130 to 210° C., about 130 to 200° C., about 130 to 190° C., about 130 to 180° C., about 130 to 170° C., about 140 to 210° C., about 140 to 200° C., about 140 to 190° C., about 140 to 180° C., and about 140 to 170° C. In the present disclosure, the melting peak temperature of a resin is a value measured by DSC.

[0048] The substrate 11 may be a single layer or multiple layers.

[0049] Furthermore, the substrate 11 can be made into a layer containing a colorant by blending a colorant into the substrate 11. When the substrate 11 is made into the colored layer 14, the substrate 11 is preferably a layer formed of a polyolefin resin containing a colorant.

[0050] Furthermore, the light transmittance can be adjusted by selecting a resin with low transparency for the substrate 11. When the substrate 11 is a film, a colored film or a film with low transparency can also be used.

[0051] When the substrate 11 is made of a resin film, the surface of the substrate 11 may be subjected to a known adhesion-facilitating treatment such as corona discharge treatment, ozone treatment, or plasma treatment, if necessary.

[0052] Furthermore, from the viewpoint of more suitably achieving the effects of the present disclosure, the thickness of the substrate 11 is preferably about 20 μm or more, more preferably about 30 μm or more, and even more preferably about 40 μm or more, and is preferably about 120 μm or less, more preferably about 110 μm or less, and even more preferably about 100 μm or less. Preferred ranges for the thickness of the substrate 11 include about 20 to 120 μm, about 20 to 110 μm, about 20 to 100 μm, about 30 to 120 μm, about 30 to 110 μm, about 30 to 100 μm, about 40 to 120 μm, about 40 to 110 μm, and about 40 to 100 μm.

[0053] [First Polyolefin Layer 12a and Second Polyolefin Layer 12b] The first polyolefin layer 12a is a layer disposed on the surface of the adhesive film for metal terminal 1 facing the exterior packaging material for an electricity storage device. That is, the first polyolefin layer 12a constitutes one surface of the adhesive film for metal terminal 1. The second polyolefin layer 12b is a layer disposed on the metal terminal 2 side. The second polyolefin layer 12b does not have to constitute the other surface of the adhesive film for metal terminal 1, but it is preferable that it constitutes the other surface of the adhesive film for metal terminal 1.

[0054] When the adhesive film for metal terminal 1 of the present disclosure is disposed between the metal terminal 2 of the electricity storage device 10 and the exterior material for an electricity storage device 3, the surface of the metal terminal 2 made of metal and the heat-sealable resin layer 35 (a layer formed of a heat-sealable resin such as polyolefin) of the exterior material for an electricity storage device 3 are bonded via the adhesive film for metal terminal 1. The first polyolefin layer 12a of the adhesive film for metal terminal 1 is disposed on the side of the exterior material for an electricity storage device 3, and the second polyolefin layer 12b is disposed on the side of the metal terminal 2, with the first polyolefin layer 12a in close contact with the heat-sealable resin layer 35 of the exterior material for an electricity storage device 3 and the second polyolefin layer 12b in close contact with the metal terminal. The first polyolefin layer 12a may be a single layer or multiple layers. The second polyolefin layer 12b may be a single layer or multiple layers.

[0055] The first polyolefin layer 12a and the second polyolefin layer 12b can each be formed, for example, from a resin film. When the first polyolefin layer 12a and the second polyolefin layer 12b are each formed from a resin film, when the first polyolefin layer 12a and the second polyolefin layer 12b are laminated with the substrate 11 or the like to produce the adhesive film for a metal terminal 1 of the present disclosure, preformed resin films may be used as the first polyolefin layer 12a and the second polyolefin layer 12b, respectively. Alternatively, the resins forming the first polyolefin layer 12a and the second polyolefin layer 12b may each be formed into a film on the surface of the substrate 11 or the like by extrusion molding, coating, or the like, to form the first polyolefin layer 12a and the second polyolefin layer 12b, etc., formed from a resin film.

[0056] The first polyolefin layer 12a and the second polyolefin layer 12b can each be made of a resin, such as polyolefin resin, polyamide resin, polyester resin, epoxy resin, acrylic resin, fluororesin, silicone resin, phenol resin, polyetherimide, polyimide, polycarbonate, and mixtures or copolymers thereof. Of these, polyolefin resin is particularly preferred.

[0057] Examples of polyolefin resins include polyolefins and acid-modified polyolefins.

[0058] Specific examples of polyolefins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred, and polypropylene is more preferred.

[0059] The acid-modified polyolefin is not particularly limited as long as it is an acid-modified polyolefin, but preferably includes polyolefins graft-modified with an unsaturated carboxylic acid or anhydride thereof. Examples of the carboxylic acid or anhydride thereof used for acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride. When a resin layer containing maleic anhydride is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is preferably detected. For example, when a maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wave number of 1760 cm. -1 Near and wave number 1780cm -1A peak derived from maleic anhydride is detected around . In the case of a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected by infrared spectroscopy. However, if the degree of acid modification is low, the peak may become small and may not be detected. In that case, analysis can be performed by nuclear magnetic resonance spectroscopy. Examples of acid-modified polyolefins include the same polyolefins as above, and similarly, preferred examples include polyethylene and polypropylene, and more preferred example is polypropylene.

[0060] The first polyolefin layer 12a disposed on the electricity storage device packaging material 3 side preferably contains polyolefin as a primary component, and even more preferably contains polypropylene as a primary component. Here, "primary component" refers to a resin component contained in the first polyolefin layer 12a whose content is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, "the first polyolefin layer 12a contains polypropylene as a primary component" means that the polypropylene content of the resin component contained in the first polyolefin layer 12a is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0061] Furthermore, the second polyolefin layer 12b disposed on the metal terminal 2 side preferably contains an acid-modified polyolefin as a main component, and even more preferably contains acid-modified polypropylene as a main component. Here, "main component" refers to a resin component contained in the second polyolefin layer 12b whose content is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, "the second polyolefin layer 12b contains acid-modified polypropylene as a main component" refers to a resin component contained in the second polyolefin layer 12b whose content is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0062] In order to more effectively exert the effects of the present disclosure, the Martens hardness of the first polyolefin layer 12a is preferably about 35 N / mm 2 Less than or equal to about 30 N / mm 2 or less, more preferably about 25 N / mm 2 or less, and preferably about 10 N / mm 2 More preferably, about 15 N / mm 2 More preferably, about 20 N / mm 2 The preferred range is 10 to 35 N / mm 2 Degree, 10~30N / mm 2 Degree, 10~25N / mm 2 Degree, 15~35N / mm 2 degree, 15~30N / mm 2 degree, 15~25N / mm 2 Degree, 20~35N / mm 2 degree, 20~30N / mm 2 degree, 20~25N / mm 2 The degree of

[0063] In order to more suitably exhibit the effects of the present disclosure, the Martens hardness of the second polyolefin layer 12b is preferably about 35 N / mm 2 Less than or equal to about 30 N / mm 2 or less, more preferably about 25 N / mm 2 or less, and preferably about 10 N / mm 2 More preferably, about 15 N / mm 2 More preferably, about 20 N / mm 2 The preferred range is 10 to 35 N / mm 2 Degree, 10~30N / mm 2 Degree, 10~25N / mm 2 Degree, 15~35N / mm 2 degree, 15~30N / mm 2 degree, 15~25N / mm 2 Degree, 20~35N / mm 2 degree, 20~30N / mm 2 degree, 20~25N / mm 2 The degree of

[0064] Furthermore, from the viewpoint of more suitably exhibiting the effects of the present disclosure, the tensile modulus of the first polyolefin layer 12a is not particularly limited, as long as the tensile modulus of the adhesive film for metal terminal 1 is 700 MPa or less. From the viewpoint of more suitably exhibiting the effects of the present disclosure, the tensile modulus of the first polyolefin layer 12a is preferably 700 MPa or less, more preferably 600 MPa or less, even more preferably 500 MPa or less, and is also preferably 100 MPa or more, more preferably 150 MPa or more, even more preferably 200 MPa or more, and preferred ranges include about 100 to 700 MPa, about 100 to 600 MPa, about 100 to 500 MPa, about 150 to 700 MPa, about 150 to 600 MPa, about 150 to 500 MPa, about 200 to 700 MPa, about 200 to 600 MPa, and about 200 to 500 MPa.

[0065] Furthermore, from the viewpoint of more suitably exhibiting the effects of the present disclosure, the tensile modulus of the second polyolefin layer 12b is not particularly limited, as long as the tensile modulus of the adhesive film for metal terminal 1 is 700 MPa or less. From the viewpoint of more suitably exhibiting the effects of the present disclosure, the tensile modulus of the second polyolefin layer 12b is preferably 700 MPa or less, more preferably 600 MPa or less, even more preferably 500 MPa or less, and is also preferably 100 MPa or more, more preferably 150 MPa or more, even more preferably 200 MPa or more, and preferred ranges include about 100 to 700 MPa, about 100 to 600 MPa, about 100 to 500 MPa, about 150 to 700 MPa, about 150 to 600 MPa, about 150 to 500 MPa, about 200 to 700 MPa, about 200 to 600 MPa, and about 200 to 500 MPa.

[0066] The melting peak temperatures of the first polyolefin layer 12a and the second polyolefin layer 12b are each preferably about 125°C or higher, more preferably about 130°C or higher, and even more preferably about 135°C or higher. The melting peak temperatures are, for example, about 180°C or lower, preferably about 175°C or lower, more preferably about 170°C or lower, even more preferably about 165°C or lower, and even more preferably about 160°C or lower. Preferred ranges of the melting peak temperature include about 125 to 180°C, about 125 to 175°C, about 125 to 170°C, about 125 to 165°C, about 125 to 160°C, about 130 to 180°C, about 130 to 175°C, about 130 to 170°C, about 130 to 165°C, about 130 to 160°C, about 135 to 180°C, about 135 to 175°C, about 135 to 170°C, about 135 to 165°C, and about 135 to 160°C.

[0067] The thickness of the first polyolefin layer 12a and the second polyolefin layer 12b is preferably about 10 μm or more, more preferably about 15 μm or more, and even more preferably about 20 μm or more, and is preferably about 120 μm or less, more preferably about 100 μm or less, and even more preferably about 80 μm or less, with preferred ranges including 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.

[0068] The first polyolefin layer 12a and the second polyolefin layer 12b may contain a known colorant (pigment or the like) to form the colored layer 14, similarly to the colored layer 14. The type and amount of pigment added are the same as those of the colored layer 14 described below.

[0069] Furthermore, for example, the first polyolefin layer 12a and the second polyolefin layer 12b may each contain a filler as necessary. When the first polyolefin layer 12a and the second polyolefin layer 12b contain a filler, the filler functions as a spacer, making it possible to effectively prevent short circuits between the metal terminal 2 and the barrier layer 33 of the packaging material 3 for an electrical storage device. The particle size of the filler is approximately 0.1 to 35 μm, preferably approximately 5.0 to 30 μm, and more preferably approximately 10 to 25 μm. The content of the filler is approximately 5 to 30 parts by mass, more preferably approximately 10 to 20 parts by mass, per 100 parts by mass of the resin components forming the first polyolefin layer 12a and the second polyolefin layer 12b, respectively.

[0070] The filler may be either inorganic or organic. Examples of inorganic fillers include carbon (carbon, graphite), silica, aluminum oxide, barium titanate, iron oxide, silicon carbide, zirconium oxide, zirconium silicate, magnesium oxide, titanium oxide, calcium aluminate, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, and calcium carbonate. Examples of organic fillers include fluororesins, phenolic resins, urea resins, epoxy resins, acrylic resins, benzoguanamine-formaldehyde condensates, melamine-formaldehyde condensates, cross-linked polymethyl methacrylates, and cross-linked polyethylenes. From the standpoints of shape stability, rigidity, and content resistance, aluminum oxide, silica, fluororesins, acrylic resins, and benzoguanamine-formaldehyde condensates are preferred, with spherical aluminum oxide and silica being particularly preferred. As a method for mixing the filler into the resin components forming the first polyolefin layer 12a and the second polyolefin layer 12b, a method in which the two are melt-blended in advance using a Banbury mixer or the like to form a masterbatch and then adjusted to a predetermined mixing ratio, or a method in which the filler is directly mixed with the resin components can be used.

[0071] [Resin layers (third layer 12c, fourth layer 12d, fifth layer 12e, etc.)] In addition to the substrate 11, the first polyolefin layer 12a, and the second polyolefin layer 12b, the adhesive film 1 for metal terminals may, if necessary, further comprise one or more resin layers such as a third layer 12c, a fourth layer 12d, and a fifth layer 12e.

[0072] 6 illustrates a laminated structure including a third layer 12c between the substrate 11 and the first polyolefin layer 12a, and a fourth layer 12d between the substrate 11 and the second polyolefin layer 12b. As described above, in the adhesive film 1 for metal terminals of the present disclosure, the first polyolefin layer 12a constitutes the surface on the exterior packaging material side for electricity storage devices, and therefore the third layer 12c, fourth layer 12d, and other resin layers are provided between the first polyolefin layer 12a and the substrate 11 and on the metal terminal 2 side of the substrate 11.

[0073] In this disclosure, if there is only one resin layer, the resin layer will be referred to as the third layer 12c; if there are two resin layers, these layers will be referred to as the third layer 12c and the fourth layer 12d; if there are three resin layers, these layers will be referred to as the third layer 12c, the fourth layer 12d, and the fifth layer 12e; and if there are four or more resin layers, the layers will be represented by increasing numbers accordingly, such as the sixth layer, the seventh layer, etc.

[0074] The resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e can each be formed, for example, from a resin film. When these resin layers are each formed from a resin film, when the resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e are laminated with the substrate 11 or the like to produce the adhesive film for a metal terminal 1 of the present disclosure, preformed resin films may each be used as these resin layers. Alternatively, the resins forming the resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e may each be formed into a film on the surface of the substrate 11 or the like by extrusion molding or coating, and used as resin layers formed from the resin film.

[0075] The resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e are each made of a resin. Examples of resins that can be used to make the resin layers include polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicone resins, phenolic resins, polyetherimides, polyimides, polycarbonates, and mixtures and copolymers thereof. Among these, polyolefin resins are particularly preferred.

[0076] Examples of polyolefin resins include the same polyolefins and acid-modified polyolefins as those exemplified for the first polyolefin layer 12a and the second polyolefin layer 12b.

[0077] The resin layer preferably contains polyolefin as a main component, and even more preferably contains polypropylene as a main component. Here, "main component" means that the content of the resin component contained in the resin layer is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, "the resin layer contains polypropylene as a main component" means that the content of polypropylene among the resin components contained in the resin layer is, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0078] Furthermore, when the resin layer forms the surface on the metal terminal 2 side, the resin layer preferably contains an acid-modified polyolefin as a main component, and even more preferably contains an acid-modified polypropylene as a main component. Here, "main component" refers to a resin component that is present in the resin layer at a content of, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more. For example, "the resin layer contains acid-modified polypropylene as a main component" refers to a resin component that is present in the resin layer at a content of, for example, 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, even more preferably 98% by mass or more, and even more preferably 99% by mass or more.

[0079] In order to more effectively exert the effects of the present disclosure, the Martens hardness of each of the resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e is preferably about 35 N / mm 2 Less than or equal to about 30 N / mm 2 or less, more preferably about 25 N / mm 2 or less, and preferably about 10 N / mm 2 More preferably, about 15 N / mm 2 More preferably, about 20 N / mm 2 The preferred range is 10 to 35 N / mm 2 Degree, 10~30N / mm 2 Degree, 10~25N / mm 2 Degree, 15~35N / mm 2 degree, 15~30N / mm 2 degree, 15~25N / mm 2 Degree, 20~35N / mm 2 degree, 20~30N / mm 2 degree, 20~25N / mm 2 However, as described above, of the layers located between the first polyolefin layer 12a and the second polyolefin layer 12b, the layer with the highest Martens hardness measured in the direction perpendicular to the cross section in the thickness direction of the layer is the substrate 11.

[0080] Furthermore, from the viewpoint of more suitably exerting the effects of the present disclosure, the tensile modulus of the resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e is not particularly limited, as long as the tensile modulus of the adhesive film 1 for metal terminals is 700 MPa or less. From the viewpoint of more suitably exerting the effects of the present disclosure, the tensile modulus of the third layer 12c, the fourth layer 12d, the fifth layer 12e, etc. is preferably about 700 MPa or less, more preferably about 600 MPa or less, and even more preferably about 500 MPa or less, and is preferably about 100 MPa or more, more preferably about 150 MPa or more, and even more preferably about 200 MPa or more. Preferred ranges include about 100 to 700 MPa, about 100 to 600 MPa, about 100 to 500 MPa, about 150 to 700 MPa, about 150 to 600 MPa, about 150 to 500 MPa, about 200 to 700 MPa, about 200 to 600 MPa, and about 200 to 500 MPa.

[0081] The melting peak temperatures of the resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e are preferably about 125° C. or higher, more preferably about 130° C. or higher, and even more preferably about 135° C. or higher. The melting peak temperatures are, for example, about 180° C. or lower, preferably about 175° C. or lower, more preferably about 170° C. or lower, even more preferably about 165° C. or lower, and even more preferably about 160° C. or lower. Preferred ranges of the melting peak temperature include about 125 to 180°C, about 125 to 175°C, about 125 to 170°C, about 125 to 165°C, about 125 to 160°C, about 130 to 180°C, about 130 to 175°C, about 130 to 170°C, about 130 to 165°C, about 130 to 160°C, about 135 to 180°C, about 135 to 175°C, about 135 to 170°C, about 135 to 165°C, and about 135 to 160°C.

[0082] The thickness of each of the resin layers, such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e, is preferably about 10 μm or more, more preferably about 15 μm or more, and even more preferably about 20 μm or more, and is preferably about 120 μm or less, more preferably about 100 μm or less, and even more preferably about 80 μm or less. Preferred ranges 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.

[0083] The resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e may contain a known colorant (pigment or the like) to form the colored layer 14, similar to the colored layer 14. The type and amount of pigment added are the same as those of the colored layer 14, which will be described later.

[0084] Furthermore, the resin layers such as the third layer 12c, the fourth layer 12d, and the fifth layer 12e may contain a filler, similar to the first polyolefin layer 12a and the second polyolefin layer 12b. The type and amount of filler added are the same as those for the first polyolefin layer 12a and the second polyolefin layer 12b.

[0085] [Colored layer 14] The colored layer 14 of the present disclosure will be described. In the present disclosure, the colored layer 14 is a colored layer. In the present disclosure, the colored layer 14 can be provided, for example, between the first polyolefin layer 12a and the second polyolefin layer 12b of the adhesive film for metal terminal 1. The colored layer 14 is a resin layer colored with a colorant. For example, any layer between the first polyolefin layer 12a and the second polyolefin layer 12b may be the colored layer 14. The colored layer 14 can also be the substrate 11, the adhesion promoter layer 13, or a resin layer (such as the third layer 12c, the fourth layer 12d, or the fifth layer 12e). FIG. 6 shows an example in which the substrate 11 constitutes the colored layer 14, and FIG. 7 shows an example in which the third layer 12c constitutes the colored layer 14. The colored layer 14 included in the adhesive film for metal terminal 1 may be a single layer or two or more layers.

[0086] The adhesive film 1 for metal terminals preferably has a colored layer 14 between the second polyolefin layer 12b and the substrate 11. It is also preferable to have a colored layer 14 between the first polyolefin layer 12a and the substrate 11. It is also preferable for the substrate 11 to be the colored layer 14.

[0087] The colored layer 14 is preferably a layer formed of a polyolefin resin containing a colorant. Examples of the polyolefin resin include the same resins as those exemplified for the first polyolefin layer 12a and the second polyolefin layer 12b.

[0088] The colored layer 14 may be formed from one type of resin component alone, or may be formed from a blend polymer of two or more types of resin components.

[0089] The colorant is not particularly limited, and any colorant capable of coloring the resin layer can be suitably used. Specific examples of colorants include pigments. Various inorganic or organic pigments can be used. Specific examples of pigments include the aforementioned fillers, such as carbon (carbon, graphite), silica, titanium oxide, iron oxide, zinc oxide, magnesium oxide, and calcium oxide, as well as inorganic oxides such as titanium nitride, zirconia black, copper oxide, cobalt oxide, and barium sulfate, as well as organic pigments such as quinacridone pigments, polyazo pigments, and isoindolinone pigments. Carbon (carbon, graphite) is a material commonly used inside electricity storage devices and is unlikely to leach into the electrolyte. Furthermore, it has a significant coloring effect, and sufficient coloring effect can be obtained even with an amount that does not impair adhesion. It also does not melt due to heat, and can increase the apparent melt viscosity of the added resin. Furthermore, it prevents the pressurized portion from becoming thin during thermal bonding (heat sealing), thereby providing excellent sealing between the electricity storage device exterior material and the metal terminal.

[0090] The color of the colored layer 14 is not particularly limited and can be selected according to the purpose. The colored layer 14 is preferably, for example, black, gray, or white.

[0091] When a pigment is added to the colored layer 14, for example, when carbon black with a particle size of approximately 0.03 μm is used, the amount of pigment added is approximately 0.05 to 0.3 parts by mass, preferably approximately 0.1 to 0.2 parts by mass, per 100 parts by mass of the resin component forming the colored layer 14. By adding a pigment to the colored layer 14, the presence or absence of the adhesive film 1 for metal terminals can be detected by a sensor or visually inspected. When the filler and pigment are added to the colored layer 14, the filler and pigment may be added to the same colored layer 14, but from the viewpoint of not impairing the thermal adhesiveness of the adhesive film 1 for metal terminals, it is preferable to add the filler and pigment separately to multiple layers.

[0092] From the viewpoint of more suitably exhibiting the effects of the present disclosure, a colored layer 14 is provided between the first polyolefin layer 12a and the second polyolefin layer 12b, and the difference in Martens hardness between the substrate 11 and the colored layer 14 is preferably about 10 N / mm 2 or less, more preferably about 8 N / mm 2 or less, and more preferably about 5 N / mm 2 The lower limit is, for example, 0 N / mm 2 and the preferred range is 0 to 10 N / mm 2 Degree, 0~8N / mm 2 Degree, 0~5N / mm 2 The degree of

[0093] From the viewpoint of more suitably exerting the effects of the present disclosure, the ratio of the thickness of the colored layer 14 of the adhesive film 1 for metal terminals to the thickness of the adhesive film 1 for metal terminals is preferably not more than about 0.30, more preferably not more than about 0.25, and even more preferably not more than about 0.20, and is also preferably not less than about 0.01, more preferably not less than about 0.03, and even more preferably not less than about 0.05, and preferred ranges include 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.

[0094] From the viewpoint of more suitably achieving the effects of the present disclosure, the thickness of the colored layer 14 is preferably about 50 μm or less, more preferably about 45 μm or less, even more preferably about 40 μm or less, even more preferably about 35 μm or less, and even more preferably about 30 μm or less, and is preferably about 3 μm or more, more preferably about 5 μm or more, and even more preferably about 10 μm or more.Preferred ranges include 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, and about 10 to 30 μm.

[0095] If necessary, known additives may be contained in the colored layer 14. The type and amount of filler added are the same as those of the first polyolefin layer 12a and the second polyolefin layer 12b.

[0096] [Adhesion promoter layer 13] The adhesion promoter layer 13 is a layer that is provided as needed, for example, for the purpose of firmly adhering the substrate 11 to the first polyolefin layer 12a and the substrate 11 to the second polyolefin layer 12b (see FIG. 5). The adhesion promoter layer 13 may be provided on only one side between the substrate 11 and the first polyolefin layer 12a and the second polyolefin layer 12b, or on both sides.

[0097] The adhesion promoter layer 13 can be formed using known adhesion promoters such as isocyanate-based, polyethyleneimine-based, polyester-based, polyurethane-based, and polybutadiene-based. From the viewpoint of obtaining strong adhesion strength, it is preferable to form the layer using an isocyanate-based adhesion promoter. Among the isocyanate-based adhesion promoters, those containing an isocyanate component selected from triisocyanate monomer and polymeric MDI provide excellent laminate strength and are less susceptible to deterioration in laminate strength at high temperatures. It is particularly preferable to form the adhesive layer using an adhesion promoter made from triphenylmethane-4,4',4"-triisocyanate, a triisocyanate monomer, or polymethylene polyphenyl polyisocyanate, a polymeric MDI (NCO content of approximately 30%, viscosity of 200 to 700 mPa·s). It is also preferable to form the adhesive layer using tris(p-isocyanatephenyl)thiophosphate, a triisocyanate monomer, or a two-component curing adhesion promoter that uses a polyethyleneimine-based compound as the main component and polycarbodiimide as the crosslinking agent.

[0098] The adhesion promoter layer 13 can be formed by coating and drying using a known coating method such as bar coating, roll coating, or gravure coating. The amount of the adhesion promoter to be applied is 20 to 100 mg / m when the adhesion promoter is made of triisocyanate. 2 Approximately, preferably 40 to 60 mg / m 2 In the case of adhesion promoters made of polymeric MDI, the concentration is 40 to 150 mg / m 2 Approximately, preferably 60 to 100 mg / m 2In the case of a two-component curing adhesion promoter that uses polyethyleneimine as the main component and polycarbodiimide as the crosslinking agent, the adhesive strength is about 5 to 50 mg / m 2 about 10 to 30 mg / m 2 Triisocyanate monomer is a monomer with three isocyanate groups in one molecule, and polymeric MDI is a mixture of MDI and MDI oligomers formed by polymerizing MDI, and is represented by the following formula:

[0099] [ka]

[0100] In order to more suitably achieve the effects of the present invention, it is preferred that the first polyolefin layer 12a and the substrate 11 are in surface contact with each other, and that the second polyolefin layer 12b and the substrate 11 are in surface contact with each other.

[0101] The adhesive film 1 for metal terminals of the present disclosure is preferably formed entirely from a polyolefin-based resin. For example, the resin components contained in the adhesive film 1 for metal terminals of the present disclosure are preferably polyolefin-based resins only, more preferably acid-modified polyolefins and polyolefins only, and even more preferably acid-modified polypropylene and polypropylene only. The preferred acid-modified polyolefins and polyolefins are as described above.

[0102] The method for interposing the adhesive film 1 for a metal terminal between the metal terminal 2 and the exterior packaging material 3 for an electricity storage device is not particularly limited, and for example, as shown in Figures 1 to 3, the adhesive film 1 for a metal terminal may be wrapped around the metal terminal 2 in the portion where the metal terminal 2 is sandwiched by the exterior packaging material 3 for an electricity storage device. Furthermore, although not shown, in the portion where the metal terminal 2 is sandwiched by the exterior packaging material 3 for an electricity storage device, the adhesive film 1 for a metal terminal may be arranged on both sides of the metal terminal 2 so as to cross the two metal terminals 2.

[0103] [Metal terminal 2] The adhesive film 1 for metal terminals of the present disclosure is used by being interposed between a metal terminal 2 and an exterior material 3 for an electricity storage device. The metal terminal 2 (tab) is a conductive member electrically connected to an electrode (positive electrode or negative electrode) of an electricity storage device element 4, and is made of a metal material. The metal material constituting the metal terminal 2 is not particularly limited, and examples thereof include aluminum, nickel, copper, etc. For example, the metal terminal 2 connected to the positive electrode of a lithium ion electricity storage device is usually made of aluminum, etc. Furthermore, the metal terminal 2 connected to the negative electrode of a lithium ion electricity storage device is usually made of copper, nickel, etc.

[0104] To enhance electrolyte resistance, the surface of the metal terminal 2 is preferably subjected to a chemical conversion treatment. For example, when the metal terminal 2 is made of aluminum, specific examples of the chemical conversion treatment include known methods for forming a corrosion-resistant film using phosphates, chromates, fluorides, triazine thiol compounds, etc. Among the methods for forming a corrosion-resistant film, a preferred method is a phosphate chromate treatment using a compound consisting of three components: a phenolic resin, a chromium (III) fluoride compound, and phosphoric acid.

[0105] The size of the metal terminal 2 may be set appropriately depending on the size of the electricity storage device to be used. The thickness of the metal terminal 2 is preferably about 50 to 1000 μm, more preferably about 70 to 800 μm. The length of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm. The width of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm.

[0106] [Exterior materials for energy storage devices 3] The electrical storage device packaging material 3 may have a laminated structure including at least a substrate layer 31, a barrier layer 33, and a heat-sealable resin layer 35, in this order. FIG. 8 shows an example of the cross-sectional structure of the electrical storage device packaging material 3, in which the substrate layer 31, an optional adhesive layer 32, a barrier layer 33, an optional adhesive layer 34, and a heat-sealable resin layer 35 are laminated in this order. In the electrical storage device packaging material 3, the substrate layer 31 is the outer layer, and the heat-sealable resin layer 35 is the innermost layer. During assembly of the electrical storage device, the electrical storage device elements 4 are sealed by bringing the heat-sealable resin layers 35 located on the peripheries of the electrical storage device elements 4 into contact with each other and heat-sealing them, thereby sealing the electrical storage device elements 4. While FIGS. 1 to 3 illustrate an electrical storage device 10 using an embossed type electrical storage device packaging material 3 formed by embossing or the like, the electrical storage device packaging material 3 may be an unformed pouch type. The pouch type includes three-sided seal, four-sided seal, pillow type, etc., and any type may be used.

[0107] The thickness of the laminate constituting the electricity storage device packaging material 10 is not particularly limited, but from the viewpoint of cost reduction, improving energy density, etc., it is, for example, about 210 μm or less, preferably about 190 μm or less, about 180 μm or less, about 155 μm or less, or about 120 μm or less. Furthermore, from the viewpoint of maintaining the function of the electricity storage device packaging material to protect the electricity storage device elements, the thickness of the laminate constituting the electricity storage device packaging material 10 is preferably about 35 μm or more, about 45 μm or more, or about 60 μm or more. Furthermore, preferred ranges for the laminate constituting the packaging material 10 for an electricity storage device include, for example, about 35 to 210 μm, about 35 to 190 μm, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 210 μm, about 45 to 190 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 210 μm, about 60 to 190 μm, about 60 to 180 μm, about 60 to 155 μm, and about 60 to 120 μm. In particular, a thickness of about 60 to 155 μm is preferred when making the electricity storage device lighter and thinner, and about 155 to 190 μm is preferred when improving formability.

[0108] (Base material layer 31) In the packaging material 3 for an electricity storage device, the base material layer 31 is a layer that functions as the base material of the packaging material for an electricity storage device, and is a layer that forms the outermost layer side.

[0109] The material for forming the base layer 31 is not particularly limited, as long as it has insulating properties. Examples of materials for forming the base layer 31 include polyester, polyamide, epoxy, acrylic resin, fluororesin, polyurethane, silicone resin, phenol, polyetherimide, polyimide, and mixtures or copolymers thereof. Polyesters such as polyethylene terephthalate and polybutylene terephthalate have the advantage of being highly resistant to electrolyte and being less susceptible to whitening due to adhesion of electrolyte, and are therefore preferably used as materials for forming the base layer 31. Furthermore, polyamide film has excellent stretchability and can prevent whitening due to resin cracking of the base layer 31 during molding, and is therefore preferably used as materials for forming the base layer 31.

[0110] The base layer 31 may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, especially a biaxially stretched resin film, is preferably used as the base layer 31 because its heat resistance is improved by oriented crystallization.

[0111] Among these, the resin film forming the base layer 31 is preferably nylon or polyester, and more preferably biaxially oriented nylon or biaxially oriented polyester.

[0112] The base material layer 31 may be formed by laminating resin films made of different materials to improve pinhole resistance and insulation when used as a package for an electricity storage device. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated together, or a multilayer structure in which a biaxially oriented polyester film and a biaxially oriented nylon film are laminated together. When the base material layer 31 has a multilayer structure, the resin films may be bonded together via an adhesive, or may be laminated together directly without an adhesive. When bonding without an adhesive, examples of methods that bond the films in a hot-melt state include coextrusion, sand lamination, and thermal lamination.

[0113] The base layer 31 may be made low-friction to improve formability. When making the base layer 31 low-friction, the coefficient of friction of the surface is not particularly limited, but may be, for example, 1.0 or less. To make the base layer 31 low-friction, for example, matte treatment, formation of a thin film layer of a slip agent, or a combination thereof may be used.

[0114] The thickness of the base layer 31 is, for example, about 10 to 50 μm, and preferably about 15 to 30 μm.

[0115] (Adhesive layer 32) In the packaging material 3 for an electricity storage device, the adhesive layer 32 is a layer that is disposed on the base material layer 31 as necessary in order to impart adhesion to the base material layer 31. In other words, the adhesive layer 32 is provided between the base material layer 31 and the barrier layer 33.

[0116] The adhesive layer 32 is formed of an adhesive capable of bonding the base material layer 31 and the barrier layer 33. The adhesive used to form the adhesive layer 32 may be a two-component curing adhesive or a one-component curing adhesive. The bonding mechanism of the adhesive used to form the adhesive layer 32 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, or the like.

[0117] The resin component of the adhesive that can be used to form the adhesive layer 32 is preferably a polyurethane-based two-component curing adhesive; polyamide, polyester, or a blend resin of these with modified polyolefin, from the viewpoint of having excellent ductility, durability under high humidity conditions, yellowing prevention, and thermal degradation prevention during heat sealing, and effectively suppressing a decrease in the laminate strength between the base layer 31 and the barrier layer 33 and preventing delamination.

[0118] Furthermore, the adhesive layer 32 may be multi-layered with different adhesive components. When the adhesive layer 32 is multi-layered with different adhesive components, it is preferable to select a resin that has excellent adhesion to the base material layer 31 as the adhesive component disposed on the base material layer 31 side, and an adhesive component that has excellent adhesion to the barrier layer 33 as the adhesive component disposed on the barrier layer 33 side, from the viewpoint of improving the laminate strength between the base material layer 31 and the barrier layer 33. When the adhesive layer 32 is multi-layered with different adhesive components, specifically, preferred examples of the adhesive component disposed on the barrier layer 33 side include acid-modified polyolefin, metal-modified polyolefin, a mixed resin of polyester and acid-modified polyolefin, and a resin containing copolymer polyester.

[0119] The thickness of the adhesive layer 32 is, for example, about 2 to 50 μm, and preferably about 3 to 25 μm.

[0120] (Barrier layer 33) In the packaging material 3 for an electricity storage device, the barrier layer 33 is a layer that not only improves the strength of the packaging material for an electricity storage device but also has the function of preventing water vapor, oxygen, light, and the like from penetrating into the interior of the electricity storage device. The barrier layer 33 is preferably a metal layer, i.e., a layer formed of a metal. Specific examples of metals constituting the barrier layer 33 include aluminum, stainless steel, and titanium, and aluminum is preferred. The barrier layer 33 can be formed, for example, from a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, or a film provided with any of these vapor deposition films. It is preferably formed from a metal foil, and more preferably from an aluminum foil. From the viewpoint of preventing the occurrence of wrinkles or pinholes in the barrier layer 33 during the production of the packaging material for an electricity storage device, it is more preferable that the barrier layer be formed from a soft aluminum foil such as annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O).

[0121] The thickness of the barrier layer 33 is preferably about 10 to 200 μm, more preferably about 20 to 100 μm, about 20 to 45 μm, about 45 to 65 μm, or about 65 to 85 μm, from the viewpoint of making the packaging material for an electricity storage device thinner while making it less likely to produce pinholes during molding.

[0122] Furthermore, it is preferable that at least one surface, and preferably both surfaces, of the barrier layer 33 be chemically treated to stabilize adhesion, prevent dissolution and corrosion, etc. Here, chemical treatment refers to a treatment for forming a corrosion-resistant film on the surface of the barrier layer.

[0123] (adhesive layer 34) In the packaging material 3 for an electricity storage device, the adhesive layer 34 is a layer that is provided as needed between the barrier layer 33 and the heat-sealable resin layer 35 in order to firmly bond the heat-sealable resin layer 35.

[0124] The adhesive layer 34 is formed of an adhesive capable of bonding the barrier layer 33 and the heat-sealable resin layer 35. The composition of the adhesive used to form the adhesive layer is not particularly limited, and examples thereof include a resin composition containing an acid-modified polyolefin. Examples of acid-modified polyolefins include the same as those exemplified for the first polyolefin layer 12a and the second polyolefin layer 12b.

[0125] The thickness of the adhesive layer 34 is, for example, about 1 to 40 μm, and preferably about 2 to 30 μm.

[0126] (Thermal adhesive resin layer 35) In the packaging material 3 for an electricity storage device, the heat-sealable resin layer 35 corresponds to the innermost layer, and is a layer that seals the electricity storage device elements by heat-sealing the heat-sealable resin layers together when assembling the electricity storage device.

[0127] The resin component used in the heat-fusible resin layer 35 is not particularly limited as long as it is heat-fusible, and examples thereof include polyolefins and cyclic polyolefins.

[0128] Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred.

[0129] The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomer constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkenes are preferred, and norbornene is more preferred. Styrene is also an example of a constituting monomer.

[0130] Among these resin components, preferred are crystalline or amorphous polyolefins, cyclic polyolefins, and blend polymers thereof; more preferred are polyethylene, polypropylene, copolymers of ethylene and norbornene, and blend polymers of two or more of these.

[0131] The heat-sealable resin layer 35 may be formed of a single resin component, or may be formed of a blend polymer of two or more resin components. The heat-sealable resin layer 35 may be formed of only one layer, or may be formed of two or more layers of the same or different resin components. It is particularly preferred that the second polyolefin layer 12b and the heat-sealable resin layer 35 use the same resin, as this improves adhesion between these layers.

[0132] The thickness of the heat-sealable resin layer 35 is not particularly limited, but may be about 2 to 2000 μm, preferably about 5 to 1000 μm, and more preferably about 10 to 500 μm. The thickness of the heat-sealable resin layer 35 is, for example, about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 34 is 10 μm or more, the thickness of the heat-sealable resin layer 35 is preferably about 85 μm or less, and more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 34 is less than 10 μm or when the adhesive layer 34 is not provided, the thickness of the heat-sealable resin layer 35 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[0133] In order to more suitably exert the effects of the present disclosure, the Martens hardness of the heat-sealable resin layer 35 is preferably about 35 N / mm 2 Less than or equal to about 30 N / mm 2 or less, more preferably about 25 N / mm 2 or less, and preferably about 10 N / mm 2 More preferably, about 15 N / mm 2 More preferably, about 18 N / mm 2 More preferably, it is about 20 N / mm 2 The preferred range is 10 to 35 N / mm 2 Degree, 10~30N / mm 2 Degree, 10~25N / mm 2 Degree, 15~35N / mm 2 degree, 15~30N / mm 2 degree, 15~25N / mm 2 Degree, 18~35N / mm 2 Degree, 18~30N / mm 2 Degree, 18~25N / mm 2 Degree, 20~35N / mm 2 degree, 20~30N / mm 2 degree, 20~25N / mm 2 The degree of

[0134] The electrical storage device exterior material of the present disclosure can also be in the form of a kit including an electrical storage device exterior material for use in an electrical storage device and the adhesive film for a metal terminal of the present disclosure. In this case, the applicable electrical storage device also includes at least an electrical storage device element including a positive electrode, a negative electrode, and an electrolyte, an electrical storage device exterior material that encapsulates the electrical storage device element, and metal terminals electrically connected to the positive electrode and the negative electrode and protruding outside the electrical storage device exterior material. When used, the kit of the present disclosure is used such that the adhesive film for a metal terminal of the present disclosure is interposed between the metal terminal and the electrical storage device exterior material.

[0135] 2. Energy storage devices An electricity storage device 10 of the present disclosure comprises at least an electricity storage device element 4 having a positive electrode, a negative electrode, and an electrolyte, an exterior material for an electricity storage device 3 that seals the electricity storage device element 4, and metal terminals 2 that are electrically connected to the positive electrode and the negative electrode, respectively, and protrude to the outside of the exterior material for an electricity storage device 3. The electricity storage device 10 of the present disclosure is characterized in that an adhesive film for a metal terminal 1 of the present disclosure is interposed between the metal terminal 2 and the exterior material for an electricity storage device 3. In other words, the electricity storage device 10 of the present disclosure can be produced by a method that includes a step of interposing an adhesive film for a metal terminal 1 of the present disclosure between the metal terminal 2 and the exterior material for an electricity storage device 3.

[0136] Specifically, an electricity storage device element 4 including at least a positive electrode, a negative electrode, and an electrolyte is placed in an electrical storage device packaging material 3, with metal terminals 2 connected to the positive and negative electrodes protruding outward, and the adhesive film 1 for metal terminals of the present disclosure is interposed between the metal terminals 2 and the heat-sealable resin layer 35, and the electrical storage device element 4 is covered around its periphery so as to form a flange portion (a region where the heat-sealable resin layers 35 contact each other, i.e., the peripheral portion 3a of the electrical storage device packaging material 3), and the heat-sealable resin layers 35 of the flange portion are heat-sealed to provide an electrical storage device 10 using the electrical storage device packaging material 3. When the electrical storage device element 4 is housed using the electrical storage device packaging material 3, the electrical storage device packaging material 3 is used so that the heat-sealable resin layer 35 of the electrical storage device packaging material 3 faces inside (the surface in contact with the electrical storage device element 4).

[0137] The exterior material for an electricity storage device of the present disclosure can be suitably used in electricity storage devices such as batteries (including condensers, capacitors, etc.). The exterior material for an electricity storage device of the present disclosure may be used in either primary or secondary batteries, but is preferably used in secondary batteries. The type of secondary battery to which the exterior material for an electricity storage device of the present disclosure is applied is not particularly limited, and examples include lithium ion batteries, lithium ion polymer batteries, all-solid-state batteries, semi-solid batteries, quasi-solid batteries, polymer batteries, all-resin batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for the exterior material for an electricity storage device of the present disclosure. [Example]

[0138] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the examples.

[0139] <Production of adhesive film for metal terminals> Example 1 Using an extruder and a T-die casting machine, a polypropylene film substrate (CPP layer (unstretched homopolypropylene layer A), 80 μm thick) was extruded onto one side as the first polyolefin layer (r-PP layer (random polypropylene layer X), 60 μm thick) on the exterior side. On the other side, a maleic anhydride-modified polypropylene containing carbon black as a black coloring layer (r-PPa layer (maleic anhydride-modified random polypropylene layer L), 60 μm thick) was extruded as the second polyolefin layer (metal terminal side) on the metal terminal side. This resulted in an adhesive film for metal terminals (total thickness 200 μm) consisting of the first polyolefin layer (r-PP layer, 60 μm thick) / substrate (CPP layer, 80 μm thick) / second polyolefin layer (r-PPa layer, 60 μm thick). The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the resin and the cooling conditions of the film-forming resin. The cooling condition at this time (the time it took for the resin extruded from the T-die to reach room temperature) was set to X seconds, which was used as the reference time for Examples 2-7 and Comparative Examples 1-3 described below. The tensile modulus of elasticity of the obtained adhesive film for metal terminal, substrate, first polyolefin layer, and second polyolefin layer, as well as the Martens hardness of each layer, are shown in Table 1.

[0140] Example 2 Using an extruder and a T-die casting machine, a polypropylene film substrate (CPP layer (unstretched homopolypropylene layer A), 60 μm thick) was extruded onto one side as the first polyolefin layer (r-PP layer (random polypropylene layer Z), 80 μm thick) on the exterior side. On the other side, a maleic anhydride-modified polypropylene containing carbon black as a black coloring layer (r-PPa layer (maleic anhydride-modified random polypropylene layer L), 60 μm thick) was extruded as the second polyolefin layer (on the metal terminal side). This resulted in an adhesive film for metal terminals (total thickness 200 μm) laminated in the following order: first polyolefin layer (r-PP layer, 60 μm thick) / substrate (CPP layer, 80 μm thick) / second polyolefin layer (r-PPa layer, 60 μm thick). The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the selected resin and the cooling conditions for the film-forming resin. The cooling time was 4 / 3X seconds. The tensile modulus of elasticity of the obtained adhesive film for metal terminal, the substrate, the first polyolefin layer, and the second polyolefin layer, as well as the Martens hardness of each layer, are shown in Table 1.

[0141] Example 3 Using an extruder and a T-die casting machine, a polypropylene film substrate (CPP layer (unstretched homopolypropylene layer A), 80 μm thick) was extruded onto one side of the film. The first polyolefin layer (r-PP layer (random polypropylene layer X), 60 μm thick) was extruded onto the other side of the film. The second polyolefin layer (r-PPa layer (maleic anhydride-modified random polypropylene layer M), 60 μm thick, contained carbon black as a black coloring layer and served as the metal terminal side. This resulted in an adhesive film for metal terminals (total thickness 200 μm) consisting of the first polyolefin layer (r-PP layer, 60 μm thick), the substrate (CPP layer, 80 μm thick), and the second polyolefin layer (r-PPa layer, 60 μm thick). The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the cooling conditions for the resin and film-forming resin. The cooling condition was defined as the time it took for the resin extruded from the T-die to reach room temperature. X seconds was used as the cooling condition. The tensile modulus of elasticity of the obtained adhesive film for metal terminal, the substrate, the first polyolefin layer, and the second polyolefin layer, as well as the Martens hardness of each layer, are shown in Table 1.

[0142] Example 4 Using an extruder and a T-die casting machine, a polypropylene film (CPP layer (unstretched homopolypropylene layer A, thickness 80 μm)) was used as a substrate. On one side of the film, a polypropylene (r-PP layer (random polypropylene layer Y), thickness 60 μm) was used as the first polyolefin layer on the exterior material side. On the other side, a maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer Y), thickness 60 μm) was used as the second polyolefin layer on the metal terminal side. A polyolefin layer (r-PP layer, thickness 60 μm) was extruded to obtain an adhesive film for metal terminals (total thickness 200 μm) in which a first polyolefin layer (r-PP layer, thickness 60 μm), a substrate (CPP layer, thickness 80 μm), and a second polyolefin layer (r-PPa layer, thickness 60 μm) were laminated in this order. The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the cooling conditions of the selected resin and film-forming resin. The cooling time was set to X seconds. The tensile modulus of the obtained adhesive film for metal terminals, substrate, first polyolefin layer, and second polyolefin layer, as well as the Martens hardness of each layer, are as shown in Table 1.

[0143] Example 5 Using an extruder and a T-die casting machine, a polypropylene film substrate (CPP layer (unstretched homopolypropylene layer B), 80 μm thick) was extruded onto one side as the first polyolefin layer on the exterior side (r-PP layer (random polypropylene layer Y), 60 μm thick). On the other side, a maleic anhydride-modified polypropylene containing carbon black as a black coloring layer (r-PPa layer (maleic anhydride-modified random polypropylene layer L), 60 μm thick) was extruded as the second polyolefin layer on the metal terminal side. This resulted in an adhesive film for metal terminals (total thickness 200 μm) consisting of the first polyolefin layer (r-PP layer, 60 μm thick), the substrate (CPP layer, 80 μm thick), and the second polyolefin layer (r-PPa layer, 60 μm thick). The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the selected resin and the cooling conditions for the film-forming resin. The cooling time was set to X seconds. The tensile modulus of elasticity of the obtained adhesive film for metal terminal, the substrate, the first polyolefin layer, and the second polyolefin layer, as well as the Martens hardness of each layer, are shown in Table 1.

[0144] Example 6 Using an extruder and a T-die casting machine, a polypropylene film (CPP layer (unstretched homopolypropylene layer C, thickness 65 μm)) was laminated on one side of the base material, and a polypropylene (r-PP layer (random polypropylene layer W, thickness 60 μm) was laminated on the other side as the first polyolefin layer on the exterior material side, and a maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer W) was laminated on the other side as the second polyolefin layer on the metal terminal side. A 75μm thick polyolefin layer (r-PP layer, 60μm thick) was extruded to obtain an adhesive film for metal terminals (total thickness 200μm) in which a first polyolefin layer (r-PP layer, 60μm thick), a substrate (CPP layer, 80μm thick), and a second polyolefin layer (r-PPa layer, 60μm thick) were laminated in this order. The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the cooling conditions of the selected resin and film-forming resin. The cooling condition was 1 / 4X seconds. The tensile modulus of the resulting adhesive film for metal terminals, substrate, first polyolefin layer, and second polyolefin layer, as well as the Martens hardness of each layer, are shown in Table 1.

[0145] Example 7 Using an extruder and a T-die casting machine, polypropylene (r-PP layer (random polypropylene layer Y), thickness 60 μm) was extruded onto one side of a polypropylene film (CPP layer (unstretched homopolypropylene layer A), thickness 80 μm) as the substrate, as the first polyolefin layer on the exterior material side, and maleic anhydride-modified polypropylene containing carbon black (r-PPa layer (maleic anhydride-modified random polypropylene layer L), thickness 20 μm) as the black colored layer on the other side, and maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer L), thickness 40 μm) as the second polyolefin layer on the metal terminal side, to obtain an adhesive film for metal terminals (total thickness 200 μm) in which the first polyolefin layer (r-PP layer, thickness 60 μm) / substrate (CPP layer, thickness 80 μm) / colored layer (r-PPa layer, thickness 20 μm) / second polyolefin layer (r-PPa layer, thickness 40 μm) were laminated in this order. The ratio of the thickness of the colored layer to the thickness of the adhesive film for metal terminals was 0.1. The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the cooling conditions of the selected resin and film-forming resin. The cooling condition was X seconds. The tensile modulus of the obtained adhesive film for metal terminals, substrate, first polyolefin layer, and second polyolefin layer, as well as the Martens hardness of each layer, are shown in Table 1.

[0146] Comparative Example 1 Using an extruder and a T-die casting machine, a polypropylene film (CPP layer (unstretched homopolypropylene layer D, thickness 80 μm)) was used as a substrate. On one side of the film, a polypropylene (r-PP layer (random polypropylene layer X), thickness 60 μm) was used as the first polyolefin layer on the exterior material side. On the other side, a maleic anhydride modified polypropylene (r-PPa layer (maleic anhydride modified random polypropylene layer X) containing carbon black as a black colored layer was used as the second polyolefin layer on the metal terminal side. A 60 μm thick layer (r-PP layer, 60 μm thick) was extruded to obtain an adhesive film for metal terminals (total thickness 200 μm) in which a first polyolefin layer (r-PP layer, 60 μm thick), a substrate (CPP layer, 80 μm thick), and a second polyolefin layer (r-PPa layer, 60 μm thick) were laminated in this order. The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the cooling conditions of the selected resin and film-forming resin. The cooling conditions were set to 1 / 2X seconds for the resin extruded from the T-die to reach room temperature. The tensile modulus of the resulting adhesive film for metal terminals, substrate, first polyolefin layer, and second polyolefin layer, as well as the Martens hardness of each layer, are listed in Table 1.

[0147] Comparative Example 2 Using an extruder and a T-die casting machine, a polypropylene film (CPP layer (unstretched homopolypropylene layer D), thickness 80 μm) was used as a substrate. On one side of the film, a polypropylene (r-PP layer (random polypropylene layer V), thickness 60 μm) was used as the first polyolefin layer on the exterior material side. On the other side, a maleic anhydride-modified polypropylene (r-PPa layer (maleic anhydride-modified random polypropylene layer V), thickness 60 μm) was used as the second polyolefin layer on the metal terminal side. L) was extruded to obtain an adhesive film for metal terminals (total thickness 200 μm) in which a first polyolefin layer (r-PP layer, thickness 60 μm), a substrate (CPP layer, thickness 80 μm), and a second polyolefin layer (r-PPa layer, thickness 60 μm) were laminated in this order. The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the cooling conditions of the selected resin and film-forming resin. The cooling condition was set to 1 / 2X second, during which the resin extruded from the T-die reached room temperature. The tensile modulus of the resulting adhesive film for metal terminals, substrate, first polyolefin layer, and second polyolefin layer, as well as the Martens hardness of each layer, are shown in Table 1.

[0148] Comparative Example 3 Using an extruder and a T-die casting machine, a polypropylene film substrate (CPP layer (unstretched homopolypropylene layer E), 80 μm thick) was extruded onto one side as the first polyolefin layer (r-PP layer (random polypropylene layer Y), 60 μm thick) on the exterior side. On the other side, a maleic anhydride-modified polypropylene containing carbon black as a black coloring layer (r-PPa layer (maleic anhydride-modified random polypropylene layer L), 60 μm thick) was extruded as the second polyolefin layer (metal terminal side) on the metal terminal side. This resulted in an adhesive film for metal terminals (total thickness 200 μm) consisting of the first polyolefin layer (r-PP layer, 60 μm thick) / substrate (CPP layer, 80 μm thick) / second polyolefin layer (r-PPa layer, 60 μm thick). The Martens hardness and tensile modulus were adjusted to obtain the desired physical properties by adjusting the resin and the cooling conditions of the film-forming resin. The cooling condition was set to 1 / 2X seconds, during which the resin extruded from the T-die reached room temperature. The tensile modulus of the resulting adhesive film for metal terminals, substrate, first polyolefin layer, and second polyolefin layer, as well as the Martens hardness of each layer, are shown in Table 1.

[0149] <Tensile modulus> The tensile modulus of the adhesive film, substrate, colored layer, first polyolefin layer, and second polyolefin layer was measured as follows. The tensile modulus of the substrate, colored layer, first polyolefin layer, and second polyolefin layer was measured by preparing each layer as a separate layer and using it as a measurement sample. These separate layers were prepared by forming a film on a polyethylene terephthalate film and peeling it off. The tensile modulus of the sample was measured in a 25°C environment in accordance with the provisions of JIS K7161-1 (ISO527-1). Specifically, the sample was cut into a strip with a width (TD) of 15 mm and a length (MD) of 50 mm. Next, in a 25°C environment, a Tensilon universal testing machine (RTG-1210 manufactured by A&D) was used to obtain stress-strain curves for the sample specimens at a tensile speed of 300 mm / min and a chuck distance of 30 mm. The tensile modulus of each sample was calculated from the slope of the line connecting the two points at 0.05% and 0.25% strain. The results are shown in Table 1.

[0150] <Martens hardness> The Martens hardness of the substrate, colored layer, first polyolefin layer, and second polyolefin layer was measured as follows. The adhesive film for metal terminals was used as a sample, and each layer laminated on the sample was measured for its Martens hardness. Specifically, the adhesive film for metal terminals was cut into a length of 30 mm and a width of 15 mm to prepare the sample. The sample was then embedded in an epoxy cold mounting resin and allowed to dry for approximately one day. The sample was then polished parallel to the TD direction using a Tegrapol-35 mechanical polishing machine manufactured by Marumoto Struers, resulting in a surface roughness of approximately 1.0 μm on the cross section. Measurements were performed using the indentation method with a Picodentor HM-500 manufactured by Fisher Instruments, with measurements taken perpendicular to the thickness cross section (the center portion of the thickness direction) of the layer being measured. The measurement conditions were as follows: The Martens hardness of the heat-sealable resin layer of the packaging material for an electricity storage device, which will be described later, was also measured in the same manner, using the packaging material for an electricity storage device as a sample and the heat-sealable resin layer laminated on the sample as the measurement object. The results are shown in Table 1.

[0151] [Martens hardness measurement conditions] The applied load was 25 mN. The load application rate was 25 mN / 20 seconds. The holding time was 5 seconds. The load unloading rate was 25 mN / 20 seconds. The indenter was a Vickers indenter with a square pyramid tip with a facing angle of 136°. The measurement temperature was 25°C. Measurements were taken 10 times at different measurement locations, and the measurement value was the average of a total of eight measurement values, excluding one maximum and one minimum value.

[0152] <Measurement of seal strength (adhesion strength) between adhesive film and exterior material> The seal strength (adhesion strength) between the adhesive film exterior material and the metal terminal was measured by the following procedure. The results are shown in Table 1.

[0153] (Fabrication of exterior materials) First, an exterior packaging material for an electricity storage device (hereinafter, sometimes simply referred to as "exterior packaging material") was prepared according to the following procedure. A substrate layer (30 μm thick) consisting of a polyethylene terephthalate film (12 μm thick), an adhesive layer (3 μm thick), and a nylon film (15 μm thick) was laminated onto an aluminum alloy foil (40 μm thick) by dry lamination, and a heat-sealable resin layer was laminated onto the other surface by coextrusion. Specifically, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied onto the nylon film to form an adhesive layer (3 μm thick) on the nylon film. Next, the adhesive layer and a polyethylene terephthalate film were laminated onto the nylon film to prepare a substrate layer. Next, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one surface of a barrier layer made of aluminum alloy foil to form an adhesive layer (3 μm thick) on the aluminum alloy foil. Next, a substrate layer with the adhesive layer and nylon film side facing the adhesive surface was laminated on the aluminum alloy foil, followed by aging treatment to produce a substrate layer / adhesive layer / barrier layer laminate. Next, an adhesive layer (40 μm thick, placed on the metal layer side) made of maleic anhydride-modified polypropylene resin and a heat-sealable resin layer (40 μm thick, innermost layer) made of random polypropylene resin were co-extruded on the barrier layer of the laminate, thereby laminating the adhesive layer / heat-sealable resin layer on the barrier layer, thereby obtaining an exterior material for an electrical storage device in which the substrate layer, adhesive layer, barrier layer, adhesive layer, and heat-sealable resin layer were laminated in this order. The Martens hardness of the heat-sealable resin layer of the resulting exterior material was 19.5 N / mm, as shown in Table 1. 2 It was.

[0154] Next, an aluminum foil (JIS H4160:1994 A8079H-O) with an MD of 25 mm, a TD of 22.5 mm, and a thickness of 400 μm was prepared as the metal terminal 2. Each adhesive film 1 obtained in the examples and comparative examples was cut to an MD of 25 mm and a TD of 20 mm. Next, as shown in the schematic diagram of FIG. 9, a metal terminal was sandwiched between two adhesive films to obtain an adhesive film / metal terminal / adhesive film laminate. At this time, the MD and TD of the metal terminal were aligned with the MD and TD of the adhesive film, respectively, and the metal terminal and adhesive film were laminated so that their centers were aligned (see FIG. 9(a)). The second polyolefin layer of the adhesive film for metal terminals was disposed on the metal terminal side. Next, the laminate was sandwiched between two polytetrafluoroethylene films (PTFE films, thickness 100 μm) and heated at a temperature of 200°C, a surface pressure of 0.25 MPa, and for 16 seconds to thermally fuse the adhesive film to the metal terminal, thereby producing a metal terminal with an adhesive film (see Figure 9(b)). Next, the packaging material 3 was cut to a size of 30 mm in TD and 100 mm in MD. As shown in the schematic diagram of Figure 10, the packaging materials were placed facing each other with the heat-sealable resin layers facing inward, and the resulting laminate was sandwiched between the opposing heat-sealable resin layers (see Figure 10(a)). The packaging materials were laminated so that the MD and TD directions of the packaging materials were aligned with the width and length directions of the laminate, respectively. In this state, a heat seal tester was used to heat seal the package at a width of 5 mm (5 mm in the y-axis direction in Figure 10(b)) at 215°C, a surface pressure of 3.0 MPa, and a time of 1.6 seconds (see the hatched area S in Figure 10(b)). The package was then naturally cooled to 25°C, yielding a laminate in which the packaging material and the adhesive film were heat-sealed (see Figure 10(b)). The resulting laminate was then cut to a width of 15 mm at the center of its short side (see the two-dot dash line in Figure 10(b) for the cutting position). Next, in a 25°C environment, the adhesive film was peeled off from the heat-sealable resin layer of the exterior material using a Tensilon universal material testing machine (RTG-1210 manufactured by A&D Corporation). The metal terminal with the adhesive film and the exterior material were chucked together to peel off the adhesive film from the heat-sealable resin layer of the exterior material. The maximum strength during peeling was recorded as the peel strength (N / 15 mm) to the exterior material. The peel speed was 5 mm / min, the peel angle was 180°, and the chuck distance was 30 mm. The average value was obtained by measuring three times.

[0155] [Table 1]

[0156] As described above, the present disclosure provides the following aspects of the invention. Item 1. An adhesive film for metal terminals that is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that encapsulates the electricity storage device element, the adhesive film for metal terminal is composed of a laminate including, in this order, at least a first polyolefin layer disposed on the surface of the exterior material for the electricity storage device, a base material, and a second polyolefin layer disposed on the metal terminal side; The adhesive film for metal terminal has a tensile modulus of 700 MPa or less, the substrate is a layer located between the first polyolefin layer and the second polyolefin layer, and has the highest Martens hardness measured in a direction perpendicular to a cross section in the thickness direction of the layer; The absolute value of the difference between the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the substrate and the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the first polyolefin layer is 10 N / mm 2 The adhesive film for metal terminals is as follows: Item 2. An adhesive film for metal terminals according to Item 1, wherein the absolute value of the difference between the tensile modulus of the substrate and the tensile modulus of the first polyolefin layer is 400 MPa or less. Item 3. An adhesive film for a metal terminal according to Item 1 or 2, wherein the tensile modulus of the second polyolefin layer is equal to or less than the tensile modulus of the substrate. Item 4. The absolute value of the difference between the tensile modulus of the first polyolefin layer and the tensile modulus of the base material is 300 MPa or less; the absolute value of the difference between the tensile modulus of the second polyolefin layer and the tensile modulus of the substrate is 300 MPa or less; Item 4. The adhesive film for metal terminal according to any one of items 1 to 3, wherein the absolute value of the difference between the tensile modulus of the first polyolefin layer and the tensile modulus of the second polyolefin layer is 300 MPa or less. Item 5. The adhesive film for a metal terminal according to any one of Items 1 to 4, further comprising a colored layer between the first polyolefin layer and the second polyolefin layer. Item 6. The adhesive film for a metal terminal according to any one of Items 1 to 5, further comprising a colored layer between the second polyolefin layer and the substrate. Item 7. A colored layer is provided between the first polyolefin layer and the second polyolefin layer, The difference between the Martens hardness of the substrate and the Martens hardness of the colored layer is 10 N / mm 2 Item 7. An adhesive film for a metal terminal according to any one of items 1 to 6, which is: Item 8. A colored layer is provided between the first polyolefin layer and the second polyolefin layer, Item 8. The adhesive film for a metal terminal according to any one of items 1 to 7, wherein the colored layer is black, gray, or white. Item 9. A colored layer is provided between the first polyolefin layer and the second polyolefin layer, Item 9. The adhesive film for a metal terminal according to any one of items 1 to 8, wherein the ratio of the thickness of the colored layer to the thickness of the adhesive film for a metal terminal is 0.30 or less. Item 10. A colored layer is provided between the first polyolefin layer and the second polyolefin layer, Item 10. The adhesive film for a metal terminal according to any one of items 1 to 9, wherein the colored layer has a thickness of 50 μm or less. Item 11. The packaging material for an electricity storage device is composed of a laminate including at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, The heat-sealable resin layer has a Martens hardness of 35 N / mm 2 Item 11. An adhesive film for a metal terminal according to any one of items 1 to 10, which is: Item 12. A method for producing an adhesive film for a metal terminal, which is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that encapsulates the electricity storage device element, comprising: the adhesive film for metal terminal is composed of a laminate including, in this order, at least a first polyolefin layer disposed on the surface of the exterior material for the electricity storage device, a base material, and a second polyolefin layer disposed on the metal terminal side; The adhesive film for metal terminal has a tensile modulus of 700 MPa or less, the substrate is a layer located between the first polyolefin layer and the second polyolefin layer, and has the highest Martens hardness measured in a direction perpendicular to a cross section in the thickness direction of the layer; The absolute value of the difference between the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the substrate and the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the first polyolefin layer is 10 N / mm 2 The following is a method for producing an adhesive film for a metal terminal. Item 13. A metal terminal with an adhesive film for a metal terminal, comprising the adhesive film for a metal terminal according to any one of Items 1 to 11 attached to a metal terminal. Item 14. An electricity storage device comprising: an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte; an exterior material for an electricity storage device that seals the electricity storage device element; and metal terminals that are electrically connected to the positive electrode and the negative electrode, respectively, and that protrude outside the exterior material for an electricity storage device, 12. An electricity storage device, wherein the adhesive film for a metal terminal according to any one of items 1 to 11 is interposed between the metal terminal and the exterior packaging material for an electricity storage device. Item 15. A method for manufacturing an electricity storage device including an electricity storage device element having at least a positive electrode, a negative electrode, and an electrolyte, an exterior material for an electricity storage device that seals the electricity storage device element, and metal terminals that are electrically connected to the positive electrode and the negative electrode, respectively, and that protrude outside the exterior material for an electricity storage device, A method for producing an electricity storage device, comprising a step of interposing the adhesive film for metal terminal according to any one of items 1 to 11 between the metal terminal and the exterior material for an electricity storage device, and sealing the electricity storage device element with the exterior material for an electricity storage device. Item 16. An exterior material for an electricity storage device for use in an electricity storage device, The electricity storage device includes at least an electricity storage device element having a positive electrode, a negative electrode, and an electrolyte, the electricity storage device exterior material sealing the electricity storage device element, and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding to the outside of the electricity storage device exterior material, and an adhesive film for metal terminals is interposed between the metal terminals and the electricity storage device exterior material, The adhesive film for a metal terminal is the adhesive film for a metal terminal according to any one of items 1 to 11, The packaging material for an electricity storage device is composed of a laminate including at least a base layer, a barrier layer, and a heat-sealable resin layer. Item 17. A kit comprising an exterior packaging material for an electricity storage device for use in an electricity storage device and the adhesive film for a metal terminal according to any one of Items 1 to 11, The electricity storage device includes at least an electricity storage device element including a positive electrode, a negative electrode, and an electrolyte, the electricity storage device exterior material sealing the electricity storage device element, and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding to the outside of the electricity storage device exterior material; The kit is used such that, when used, the adhesive film for a metal terminal is interposed between the metal terminal and the exterior material for an electricity storage device. [Explanation of symbols]

[0157] 1. Adhesive film for metal terminals 2 metal terminals 3. Exterior materials for energy storage devices 3a Peripheral part of the exterior material for the electricity storage device 4. Energy storage device elements 10. Energy storage devices 11 Base material 12a First polyolefin layer 12b Second polyolefin layer 12c 3rd layer (resin layer) 12d 4th layer (resin layer) 14 Colored layer 31 Base material layer 32 Adhesive layer 33 Barrier Layer 34 Adhesive layer 35 Heat-fusible resin layer

Claims

1. An adhesive film for metal terminals, which is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element, the adhesive film for metal terminal is composed of a laminate including, in this order, at least a first polyolefin layer disposed on a surface of the exterior material for an electricity storage device, a base material, and a second polyolefin layer disposed on the metal terminal side; The adhesive film for metal terminal has a tensile modulus of 700 MPa or less, the substrate is a layer located between the first polyolefin layer and the second polyolefin layer, and has the highest Martens hardness measured in a direction perpendicular to a cross section in a thickness direction of the layer; The absolute value of the difference between the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the substrate and the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the first polyolefin layer is 10 N / mm 2 The adhesive film for metal terminals is as follows:

2. 2. The adhesive film for metal terminal according to claim 1, wherein the absolute value of the difference between the tensile modulus of the substrate and the tensile modulus of the first polyolefin layer is 400 MPa or less.

3. 3. The adhesive film for a metal terminal according to claim 1, wherein the tensile modulus of elasticity of the second polyolefin layer is equal to or less than the tensile modulus of elasticity of the substrate.

4. the absolute value of the difference between the tensile modulus of the first polyolefin layer and the tensile modulus of the substrate is 300 MPa or less; the absolute value of the difference between the tensile modulus of the second polyolefin layer and the tensile modulus of the substrate is 300 MPa or less; 3. The adhesive film for metal terminal according to claim 1, wherein the absolute value of the difference between the tensile modulus of the first polyolefin layer and the tensile modulus of the second polyolefin layer is 300 MPa or less.

5. The adhesive film for a metal terminal according to claim 1 or 2, further comprising a colored layer between the first polyolefin layer and the second polyolefin layer.

6. The adhesive film for a metal terminal according to claim 1 or 2, further comprising a colored layer between the second polyolefin layer and the substrate.

7. a colored layer is provided between the first polyolefin layer and the second polyolefin layer; The difference between the Martens hardness of the substrate and the Martens hardness of the colored layer is 10 N / mm 2 The adhesive film for metal terminal according to claim 1 or 2, wherein:

8. a colored layer is provided between the first polyolefin layer and the second polyolefin layer; The adhesive film for a metal terminal according to claim 1 or 2, wherein the colored layer is black, gray, or white.

9. a colored layer is provided between the first polyolefin layer and the second polyolefin layer; 3. The adhesive film for a metal terminal according to claim 1, wherein the ratio of the thickness of the colored layer to the thickness of the adhesive film for a metal terminal is 0.30 or less.

10. a colored layer is provided between the first polyolefin layer and the second polyolefin layer; 3. The adhesive film for a metal terminal according to claim 1, wherein the colored layer has a thickness of 50 [mu]m or less.

11. the packaging material for an electricity storage device is composed of a laminate including at least a base layer, a barrier layer, and a heat-sealable resin layer in this order; The heat-sealable resin layer has a Martens hardness of 35 N / mm 2 The adhesive film for metal terminal according to claim 1 or 2, wherein:

12. A method for producing an adhesive film for a metal terminal, which is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that encapsulates the electricity storage device element, comprising: the adhesive film for metal terminal is composed of a laminate including, in this order, at least a first polyolefin layer disposed on a surface of the exterior material for an electricity storage device, a base material, and a second polyolefin layer disposed on a metal terminal side; The adhesive film for metal terminal has a tensile modulus of 700 MPa or less, the substrate is a layer located between the first polyolefin layer and the second polyolefin layer, and has the highest Martens hardness measured in a direction perpendicular to a cross section in a thickness direction of the layer; The absolute value of the difference between the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the substrate and the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the first polyolefin layer is 10 N / mm 2 The following is a method for producing an adhesive film for a metal terminal.

13. A metal terminal with an adhesive film for a metal terminal, comprising the adhesive film for a metal terminal according to claim 1 or 2 attached to a metal terminal.

14. An electricity storage device comprising: an electricity storage device element including at least a positive electrode, a negative electrode, and an electrolyte; an exterior material for an electricity storage device that seals the electricity storage device element; and metal terminals that are electrically connected to the positive electrode and the negative electrode, respectively, and that protrude outside the exterior material for an electricity storage device, An electricity storage device, comprising the adhesive film for metal terminals according to claim 1 or 2 interposed between the metal terminals and the exterior material for electricity storage devices.

15. A method for manufacturing an electricity storage device including at least an electricity storage device element including a positive electrode, a negative electrode, and an electrolyte, an exterior material for an electricity storage device that seals the electricity storage device element, and metal terminals that are electrically connected to the positive electrode and the negative electrode, respectively, and that protrude outside the exterior material for an electricity storage device, 3. A method for manufacturing an electricity storage device, comprising a step of interposing the adhesive film for metal terminals according to claim 1 or 2 between the metal terminals and the exterior material for an electricity storage device, and sealing the electricity storage device elements with the exterior material for an electricity storage device.

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

17. A kit comprising an exterior material for an electricity storage device for use in an electricity storage device and the adhesive film for a metal terminal according to claim 1 or 2, The electricity storage device includes at least an electricity storage device element including a positive electrode, a negative electrode, and an electrolyte, the electricity storage device exterior material sealing the electricity storage device element, and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding to the outside of the electricity storage device exterior material; The kit is used such that, when used, the adhesive film for a metal terminal is interposed between the metal terminal and the exterior material for an electricity storage device.

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