Adhesive film for metal terminal, method for manufacturing adhesive film for metal terminal, metal terminal with adhesive film for metal terminal, electricity storage device using adhesive film for metal terminal, and method for manufacturing electricity storage device

Abstract

To provide a metal terminal adhesive film excellent in followability to a shape of a metal terminal at heat sealing and excellent in bendability.SOLUTION: Provided is a metal terminal adhesive film interposed between a metal terminal electrically connected with an electrode of a power storage device element and a power storage device sheath material for encapsulating the power storage device element. The metal terminal adhesive film is configured by a laminate at least comprising a polyolefin layer arranged at the metal terminal side and a resin layer arranged at the power storage device sheath material side in this order. Martens hardness of the polyolefin layer measured in a direction perpendicular to a cross section in a thickness direction of the polyolefin layer under a predetermined measurement condition, is equal to or less than 37 N / mm2. The resin layer includes a layer whose Martens hardness measured in a direction perpendicular to a cross section in a thickness direction of the resin layer under the predetermined measurement condition is equal to or less than 98 N / mm2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an adhesive film for metal terminals, a method for manufacturing an adhesive film for metal terminals, a metal terminal with an adhesive film for metal terminals, an electricity storage device using the adhesive film for metal terminals, and a method for manufacturing an electricity storage device. [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 material 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 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] As described above, the adhesive film is disposed between the heat-sealable resin layer of the electrical storage device packaging material and the metal terminal, and adheres the metal terminal to the heat-sealable resin layer of the electrical storage device packaging material. In this case, if a gap is formed between the adhesive film and the metal terminal, a problem occurs in which the electrolyte, which is the content of the electrical storage device, leaks out of the electrical storage device. Therefore, the adhesive film is required to have excellent conformability so that, when heat-sealed to the metal terminal, the adhesive film conforms to the shape of the metal terminal and no gap is formed between the adhesive film and the metal terminal.

[0008] Furthermore, the adhesive film may be folded to accommodate it inside the exterior packaging material for an electricity storage device, and therefore it is preferable that the adhesive film have excellent foldability.

[0009] However, conventional adhesive films are not necessarily sufficient in terms of achieving both conformability and foldability, and the inventors of the present disclosure have sought to further improve conformability and foldability.

[0010] In light of these circumstances, a primary object of the present disclosure is to provide an adhesive film for metal terminals that exhibits excellent conformability to the shape of the metal terminal during heat sealing and also exhibits excellent foldability. Further, the present disclosure also aims to provide a method for manufacturing the adhesive film for metal terminals, a metal terminal equipped with the adhesive film for metal terminals that utilizes the adhesive film for metal terminals, an electricity storage device that utilizes the adhesive film for metal terminals, and a method for manufacturing the electricity storage device. [Means for solving the problem]

[0011] The inventors of the present disclosure conducted extensive research to solve the above-mentioned problems. As a result, they discovered that an adhesive film for metal terminals, which is composed of a laminate including, in this order, a polyolefin layer disposed on the metal terminal side and a resin layer disposed on the electrical storage device exterior packaging material side, can exhibit excellent conformability to the shape of the metal terminal during heat sealing and excellent foldability by setting the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the polyolefin layer to a predetermined value or less under predetermined measurement conditions, and further setting the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the resin layer to a predetermined value or less. The present disclosure was completed through further research based on this finding.

[0012] 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 a metal terminal is composed of a laminate including at least a polyolefin layer disposed on the metal terminal side and a resin layer disposed on the exterior material for an electricity storage device side, in this order; The polyolefin layer has a Martens hardness of 37 N / mm when measured in a direction perpendicular to a cross section in the thickness direction of the polyolefin layer under the following measurement conditions: 2 is as follows: The resin layer has a Martens hardness of 98 N / mm when measured in a direction perpendicular to a cross section in the thickness direction of the resin layer under the following measurement conditions: 2 1. An adhesive film for a metal terminal, comprising: <Measurement conditions for Martens hardness> The applied load is 10 mN. The load application rate is 1 mN / 10 seconds. The holding time is 10 seconds. The loading and unloading rate is 1 mN / 10 seconds. The indenter is a Vickers indenter with a square pyramid-shaped tip with an opposing angle of 136°. The measurement temperature is 25°C. The measurement values ​​were measured 10 times at different measurement locations, and the average value of a total of eight measurement values ​​was calculated, excluding one maximum value and one minimum value. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to provide an adhesive film for metal terminals that has excellent conformability to the shape of the metal terminal during heat sealing and also has excellent foldability. Further, the present disclosure also aims to provide a method for manufacturing the adhesive film for metal terminals, a metal terminal with an adhesive film for metal terminals that uses the adhesive film for metal terminals, an electricity storage device that uses the adhesive film for metal terminals, and a method for manufacturing the electricity storage device. [Brief explanation of the drawings]

[0014] [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 exterior packaging material for an electricity storage device according to the present disclosure. [Figure 7] This is a schematic cross-sectional view of an adhesive film / metal terminal / adhesive film laminate (metal terminal with adhesive film for metal terminal) obtained in an example by sandwiching a metal terminal between two adhesive films and heat-sealing them. [Figure 8] FIG. 1 is an image of a graph showing the relationship between indentation depth (μm) and load (mN) obtained by measuring Martens hardness, indentation modulus, and indentation depth hmax. [Figure 9] FIG. 2 is a schematic diagram illustrating a method for measuring Martens hardness by pressing an indenter perpendicularly into a cross section in the thickness direction of a polyolefin layer of an adhesive film for a metal terminal. DETAILED DESCRIPTION OF THE INVENTION

[0015] The adhesive film for metal terminals of the present disclosure is an adhesive film for metal terminals that is interposed between a metal terminal electrically connected to an electrode of an electricity storage device element and an exterior material for an electricity storage device that seals the electricity storage device element, and the adhesive film for metal terminals is composed of a laminate that includes, in this order, at least a polyolefin layer that is disposed on the metal terminal side and a resin layer that is disposed on the exterior material for an electricity storage device, and the polyolefin layer has a Martens hardness of 37 N / mm2 measured in a direction perpendicular to a cross section in the thickness direction of the polyolefin layer under the following measurement conditions: 2 The resin layer has a Martens hardness of 98 N / mm or less, measured in a direction perpendicular to a cross section in the thickness direction of the resin layer under the following measurement conditions: 2The adhesive film for metal terminal of the present disclosure is characterized by including the following layer: By having this configuration, the adhesive film for metal terminal of the present disclosure exhibits excellent conformability to the shape of the metal terminal during heat sealing and also excellent foldability.

[0016] <Measurement conditions for Martens hardness> The applied load is 10 mN. The load application rate is 1 mN / 10 seconds. The holding time is 10 seconds. The loading and unloading rate is 1 mN / 10 seconds. The indenter is a Vickers indenter with a square pyramid-shaped tip with an opposing angle of 136°. The measurement temperature is 25°C. The measurement values ​​were measured 10 times at different measurement locations, and the average value of a total of eight measurement values ​​was calculated, excluding one maximum value and one minimum value.

[0017] In the present disclosure, the Martens hardness of an adhesive film for metal terminals is measured by pressing an indenter against a cross section of the layer of the adhesive film for metal terminals to be measured in the thickness direction y (i.e., a cross section obtained by cutting the adhesive film for metal terminals in the thickness direction), in the direction x perpendicular to the thickness direction y, to measure the Martens hardness. For example, to explain a method for measuring the Martens hardness of a polyolefin layer, as shown in the schematic diagram of Figure 9, an indenter is pressed against a cross section of the polyolefin layer 11 of the adhesive film for metal terminals 1 in the thickness direction y (i.e., a cross section obtained by cutting the adhesive film for metal terminals 1 in the thickness direction), in the direction x perpendicular to the thickness direction y (arrow in Figure 9), to measure the Martens hardness.

[0018] The adhesive film for metal terminals of the present disclosure has a Martens hardness of 37 N / mm when measured in a direction perpendicular to a cross section in the thickness direction of the polyolefin layer. 2 or less, and further, the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the resin layer is 98 N / mm 2 By including the following layer, excellent conformability to the shape of the metal terminal during heat sealing and excellent bendability are both achieved.

[0019] The present disclosure also provides 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 encapsulates the electricity storage device element, and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, and protruding outside the exterior material for an electricity storage device, wherein the adhesive film for a metal terminal of the present disclosure is interposed between the metal terminal and the exterior material for an electricity storage device. The adhesive film for a metal terminal and a method for manufacturing the same of the present disclosure, and an electricity storage device using the adhesive film for a metal terminal and a method for manufacturing the same are described in detail below.

[0020] In this specification, numerical ranges indicated with "to" mean "greater than or equal to" or "less than or equal to." For example, the expression 2 to 15 mm means 2 mm or greater and 15 mm or less.

[0021] 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 a polyolefin layer and a resin 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 an electron microscope photograph of 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. 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 perpendicular 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 shapes is largest is determined as the MD. Alternatively, for example, the adhesive film for metal terminals can be left in a 150°C environment for 2 minutes, and the thermal shrinkage rate measured, and the larger shrinkage rate can be determined as MD.

[0022] Furthermore, in the adhesive film for metal terminals of the present disclosure, the "metal terminal side" of the polyolefin layer arranged on the metal terminal side means that the polyolefin layer is located relatively closer to the metal terminal than the resin layer. Furthermore, in the adhesive film for metal terminals of the present disclosure, the "electricity storage device sheathing material side" of the resin layer arranged on the electricity storage device sheathing material side means that the resin layer is located relatively closer to the electricity storage device sheathing material side than the polyolefin layer. That is, in the present disclosure, the "metal terminal side" and the "electricity storage device sheathing material side" refer to the relative positional relationships of the polyolefin layer and the resin layer, respectively.

[0023] Furthermore, one method for confirming the MD of an adhesive film for metal terminals is to observe the cross section of the adhesive film for metal terminals (for example, the cross section of a polyolefin layer, a resin layer (substrate, polyester layer)) with 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 shape in the direction perpendicular to the thickness direction of the adhesive film for metal terminals is the largest can be determined to be the MD. Specifically, the angle is changed by 10 degrees from the direction parallel to the cross section in the length direction of the adhesive film for metal terminals and the cross section in the length direction, and the Each cross section (10 cross sections in total) up to the direction perpendicular to the cross section in the thickness direction is observed using an electron microscope to confirm the sea-island structure. Next, the shape of each individual island is observed in each cross section. For each island shape, the straight-line 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 that direction is defined as the diameter y. For each cross section, the average of the diameters y of the top 20 island shapes in descending order of diameter y is calculated. The direction parallel to the cross section with the largest average diameter y of the island shape is determined to be MD.

[0024] 1. Adhesive film for metal terminals The adhesive film for metal terminals 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 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 metal terminal 1, at a peripheral portion 3a of the heat-sealed exterior material for an electricity storage device 3. In the present disclosure, the heating temperature when heat-sealing the exterior material for an electricity storage device is typically in the range of about 160 to 190°C, and the pressure is typically in the range of about 1.0 to 2.0 MPa. In the process of bonding a metal terminal and an exterior material for an electricity storage device via an adhesive film, heating and pressure are typically applied multiple times, for example, in a temporary bonding process to the metal terminal and a main bonding process. The temporary bonding process is a process of temporarily attaching the adhesive film to the metal terminal and removing air bubbles, while the main bonding process is a process of bonding the adhesive film to the metal terminal by applying heat and pressure once or multiple times under higher temperature conditions than in the temporary bonding process. The temporary bonding process of the adhesive film for a metal terminal to the metal terminal is carried out under conditions such as a temperature of about 140 to 160°C, a pressure of about 0.01 to 1.0 MPa, a time of about 3 to 15 seconds, and a number of times of about 3 to 6, while the main bonding process is carried out under conditions such as a temperature of about 160 to 240°C, a pressure of about 0.01 to 1.0 MPa, a time of about 3 to 15 seconds, and a number of times of about 1 to 3.

[0025] The adhesive film 1 for metal terminals of the present disclosure is provided to improve adhesion between the metal terminal 2 and the exterior packaging material 3 for an electricity storage device. Improved adhesion between the metal terminal 2 and the exterior packaging material 3 for an electricity storage device improves the sealing performance 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 exterior packaging material 3 for an electricity storage device. 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 exterior packaging material 3 for an electricity storage device are made of different materials. Therefore, without using such an adhesive film, the sealing performance of the electricity storage device element is likely to be reduced at the interface between the metal terminal 2 and the heat-sealable resin layer 35.

[0026] As shown in FIGS. 4 and 5, the adhesive film 1 for metal terminals of the present disclosure includes a laminated structure of at least a polyolefin layer 11 and a resin layer 12. The resin layer 12 can be composed of at least one layer selected from a substrate layer, a polyester layer, and a polyolefin layer. The laminated structure of the adhesive film 1 for metal terminals of the present disclosure is preferably a laminated structure in which the polyolefin layer 11 is laminated in this order with a substrate layer and a polyester layer as the resin layer 12; or a laminated structure in which the polyolefin layer 11 is laminated in this order with a substrate layer and a polyolefin layer as the resin layer 12. When the resin layer 12 includes a polyolefin layer, the polyolefin layer, like the polyolefin layer 11, is a layer containing a polyolefin-based resin, and examples of polyolefin-based resins include polyolefins and acid-modified polyolefins. Like the polyolefin layer 11, the polyolefin layer preferably contains an acid-modified polyolefin among polyolefin-based resins, and more preferably is a layer formed from an acid-modified polyolefin. In particular, the resin layer 12 preferably includes at least one of the substrate 12b located on the polyolefin layer 11 side and the polyester layer 12a constituting the surface of the adhesive film for metal terminal 1 on the side of the exterior material for an electricity storage device 3, and more preferably includes the substrate 12b and the polyester layer 12a. That is, the adhesive film for metal terminal 1 of the present disclosure preferably has a laminated configuration in which at least the polyolefin layer 11, the substrate 12b, and the polyester layer 12a are laminated in this order. In the present disclosure, the polyolefin layer 11 is disposed on the metal terminal side. Furthermore, the resin layer 12 is disposed on the side of the exterior material for an electricity storage device 3. In the adhesive film for metal terminal 1 of the present disclosure, it is preferred that one surface be constituted by the polyolefin layer 11 and the other surface be constituted by the polyester layer 12a.

[0027] In the adhesive film for metal terminal 1 of the present disclosure, the polyolefin layer 11 is a layer containing a polyolefin-based resin. Examples of polyolefin-based resins include polyolefins and acid-modified polyolefins. Among polyolefin-based resins, the polyolefin layer 11 preferably contains an acid-modified polyolefin, and is more preferably a layer formed from an acid-modified polyolefin.

[0028] The resin layer 12 is a layer containing a resin, and the resin is not particularly limited.

[0029] In the resin layer 12, the polyester layer 12a is a layer containing a polyester-based resin. As described below, the polyester layer 12a preferably contains at least one of polyethylene terephthalate and polybutylene terephthalate as a polyester-based resin, and more preferably polybutylene terephthalate. Furthermore, by using the same resin (e.g., polybutylene terephthalate) as the resin forming the polyester layer 12a arranged on the side of the electrical storage device sheathing material 3 as the resin forming the heat-sealable resin layer 35 of the electrical storage device sheathing material 3, the adhesion between the adhesive film for metal terminal 1 of the present disclosure and the electrical storage device sheathing material can be improved. Furthermore, in the adhesive film for metal terminal 1 of the present disclosure, by arranging the polyester layer 12a on the side of the electrical storage device sheathing material 3, excessive crushing of the adhesive film for metal terminal 1 during heat sealing can be suppressed.

[0030] In the resin layer 12, the base material 12b preferably contains a polyolefin resin, more preferably contains a polyolefin, and is more preferably a layer formed of a polyolefin.

[0031] A specific example of the laminated structure of the adhesive film 1 for metal terminals of the present disclosure is a three-layer structure in which a polyolefin layer 11 formed from acid-modified polypropylene, a substrate 12b formed from polypropylene, and a polyester layer 12a formed from polybutylene terephthalate are laminated in this order.

[0032] The materials constituting the polyolefin layer 11, the polyester layer 12a and the base material 12b will be described in detail later.

[0033] When the adhesive film 1 for metal terminals of the present disclosure is placed between the metal terminal 2 of the electricity storage device 10 and the exterior material 3 for electricity storage devices, 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 or polyester) of the exterior material 3 for electricity storage devices are bonded via the adhesive film for metal terminals 1. For example, the polyolefin layer 11 of the adhesive film 1 for metal terminals is placed on the metal terminal 2 side, and the polyester layer 12a of the resin layer 12 is placed on the exterior material 3 for electricity storage devices, with the polyolefin layer 11 in close contact with the metal terminal 2 and the polyester layer 12a in close contact with the heat-sealable resin layer 35 of the exterior material 3 for electricity storage devices.

[0034] In the adhesive film for metal terminal 1 of the present disclosure, the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the polyolefin layer 11 is 37 N / mm 2 The resin layer 12 has a Martens hardness of 98 N / mm2 or less when measured in a direction perpendicular to the cross section in the thickness direction. 2 More specifically, the resin layer 12 has a Martens hardness of 98 N / mm or less, measured in a direction perpendicular to a cross section in the thickness direction of at least one of the base material 12b and the polyester layer 12a. 2The adhesive film 1 for metal terminals of the present disclosure has high flexibility in the polyolefin layer 11 arranged on the metal terminal 2 side, and the resin layer 12 is not too hard, so it can exhibit excellent conformability and bendability around the metal terminal 2. While not wishing to be limited in any way, it is believed that the high flexibility of the polyolefin layer 11 and the not too hard resin layer 12 allow the polyolefin layer 11 to easily fill the gap formed between the metal terminal and the exterior material for an electricity storage device, and also allow the polyolefin layer 11 to easily wrap around the metal terminal in the thickness direction, thereby exhibiting excellent conformability to the metal terminal 2 and even excellent bendability. The conditions for measuring the Martens hardness are as follows. To pretreat the sample to be measured, the adhesive film for metal terminals is cut to a measurable size (e.g., MD 30 mm, TD 15 mm). Next, the sample is embedded in an epoxy cold mounting resin and allowed to dry for about one day. The cross section obtained by cutting in the TD direction was then polished using a Tegrapol-35 mechanical polishing machine manufactured by Marumoto Struers, to a surface roughness of approximately 1.0 μm. Martens hardness was measured using the indentation method. Measurements using the indentation method can be performed, for example, using a Picodentor HM-500 manufactured by Fisher Instruments.

[0035] <Measurement conditions for Martens hardness> The applied load is 10 mN. The load application rate is 1 mN / 10 seconds. The holding time is 10 seconds. The loading and unloading rate is 1 mN / 10 seconds. The indenter is a Vickers indenter with a square pyramid-shaped tip with an opposing angle of 136°. The measurement temperature is 25°C. The measurement values ​​were measured 10 times at different measurement locations, and the average value of a total of eight measurement values ​​was calculated, excluding one maximum value and one minimum value.

[0036] The Martens hardness of the polyolefin layer 11 is 37 N / mm 2However, from the viewpoint of more suitably exhibiting excellent conformability to the metal terminal 2 and excellent bendability, it 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 Below 20 N / mm, particularly preferably about 20 N / mm 2 The Martens hardness of the polyolefin layer 11 is preferably about 3 N / mm 2 More preferably, about 5N / mm 2 More preferably, about 8N / mm 2 The preferred range of the Martens hardness of the polyolefin layer 11 is 3 to 37 N / mm 2 Degree, 3~35N / mm 2 Degree, 3~30N / mm 2 Degree, 3~25N / mm 2 Degree, 3~20N / mm 2 Degree, 5~37N / mm 2 Degree, 5~35N / mm 2 Degree, 5~30N / mm 2 Degree, 5~25N / mm 2 Degree, 5~20N / mm 2 Degree, 8~37N / mm 2 Degree, 8~35N / mm 2 Degree, 8~30N / mm 2 Degree, 8~25N / mm 2 Degree, 8~20N / mm 2 The degree of

[0037] To further suitably exhibit excellent conformability to the metal terminal 2 and excellent bendability, the indentation modulus of the polyolefin layer 11 measured in a direction perpendicular to the thickness cross section under the Martens hardness measurement conditions is preferably about 700 MPa or less, more preferably about 550 MPa or less, even more preferably about 500 MPa or less, even more preferably about 350 MPa or less, and particularly preferably about 200 MPa or less. The indentation modulus of the polyolefin layer 11 is preferably about 100 MPa or more, more preferably about 120 MPa or more, and even more preferably about 150 MPa or more. Preferred ranges for the indentation elastic modulus of the polyolefin layer 11 include about 100 to 700 MPa, about 100 to 550 MPa, about 100 to 500 MPa, about 100 to 350 MPa, about 100 to 200 MPa, about 120 to 700 MPa, about 120 to 550 MPa, about 120 to 500 MPa, about 120 to 350 MPa, about 120 to 200 MPa, about 150 to 700 MPa, about 150 to 550 MPa, about 150 to 500 MPa, about 150 to 350 MPa, and about 150 to 200 MPa.

[0038] In order to more suitably exhibit excellent conformability to the metal terminal 2 and excellent bendability, the Martens hardness is measured in the direction perpendicular to the cross section of the polyolefin layer 11 in the thickness direction under the conditions for measuring the Martens hardness, i.e., an indentation depth h at a load of 10 mN. max is preferably about 3.0 μm or more, more preferably about 3.5 μm or more, even more preferably about 3.8 μm or more, even more preferably about 4.0 μm or more, even more preferably about 4.5 μm or more, and particularly preferably about 5.0 μm or more. max The indentation depth h of the polyolefin layer 11 is preferably about 10.0 μm or less, more preferably about 8.0 μm or less, and even more preferably about 7.0 μm or less. maxPreferred ranges include about 3.0 to 10.0 μm, about 3.0 to 8.0 μm, about 3.0 to 7.0 μm, about 3.5 to 10.0 μm, about 3.5 to 8.0 μm, about 3.5 to 7.0 μm, about 3.8 to 10.0 μm, about 3.8 to 8.0 μm, about 3.8 to 7.0 μm, about 4.0 to 10.0 μm, about 4.0 to 8.0 μm, about 4.0 to 7.0 μm, about 4.5 to 10.0 μm, about 4.5 to 8.0 μm, and about 4.5 to 7.0 μm.

[0039] The Martens hardness measured in a direction perpendicular to the cross section of the resin layer 12 in the thickness direction is 98 N / mm 2 However, from the viewpoint of more suitably exhibiting excellent conformability to the metal terminal 2 and excellent bendability, the Martens hardness is preferably about 95 N / mm 2 Less than or equal to about 60 N / mm 2 or less, more preferably about 45 N / mm 2 or less, more preferably about 40 N / mm 2 The Martens hardness is preferably about 8 N / mm 2 More preferably, about 15 N / mm 2 More preferably, about 20 N / mm 2 More preferably, about 25 N / mm 2 More than 30N / mm 2 The preferred range of the Martens hardness is 8 to 98 N / mm 2 Degree, 8~95N / mm 2 Degree, 8~60N / mm 2 Degree, 8~45N / mm 2 Degree, 8~40N / mm 2 degree, 15~98N / mm 2 Degree, 15~95N / mm 2 degree, 15~60N / mm 2 Degree, 15~45N / mm 2 degree, 15~40N / mm 2 degree, 20~98N / mm 2 Degree, 20~95N / mm 2 Degree, 20~60N / mm 2degree, 20~45N / mm 2 Degree, 20~40N / mm 2 degree, 25~98N / mm 2 Degree, 25~95N / mm 2 degree, 25~60N / mm 2 degree, 25~45N / mm 2 degree, 25~40N / mm 2 degree, 30~98N / mm 2 Degree, 30~95N / mm 2 degree, 30~60N / mm 2 degree, 30~45N / mm 2 degree, 30~40N / mm 2 The degree of

[0040] When the resin layer 12 includes a polyester layer 12a, the Martens hardness measured in the direction perpendicular to the cross section in the thickness direction of the polyester layer 12a is preferably 98 N / mm 2 or less, more preferably about 95 N / mm 2 or less, more preferably about 60 N / mm 2 or less, more preferably about 45 N / mm 2 or less, more preferably about 40 N / mm 2 The Martens hardness is preferably about 8 N / mm 2 More preferably, about 15 N / mm 2 More preferably, about 20 N / mm 2 More preferably, about 25 N / mm 2 More than 30N / mm 2 The preferred range of the Martens hardness of the polyester layer 12a is 8 to 98 N / mm 2 Degree, 8~95N / mm 2 Degree, 8~60N / mm 2 Degree, 8~45N / mm 2 Degree, 8~40N / mm 2 degree, 15~98N / mm 2 Degree, 15~95N / mm 2 degree, 15~60N / mm 2 Degree, 15~45N / mm 2degree, 15~40N / mm 2 degree, 20~98N / mm 2 Degree, 20~95N / mm 2 Degree, 20~60N / mm 2 degree, 20~45N / mm 2 Degree, 20~40N / mm 2 degree, 25~98N / mm 2 Degree, 25~95N / mm 2 degree, 25~60N / mm 2 degree, 25~45N / mm 2 degree, 25~40N / mm 2 degree, 30~98N / mm 2 Degree, 30~95N / mm 2 degree, 30~60N / mm 2 degree, 30~45N / mm 2 degree, 30~40N / mm 2 The degree of

[0041] Furthermore, when the resin layer 12 includes a substrate 12b, the Martens hardness measured in a direction perpendicular to the cross section in the thickness direction of the substrate 12b under the above-mentioned Martens hardness measurement conditions is preferably 98 N / mm 2 or less, more preferably about 95 N / mm 2 or less, more preferably about 60 N / mm 2 or less, more preferably about 45 N / mm 2 or less, more preferably about 40 N / mm 2 The Martens hardness is preferably about 8 N / mm 2 More preferably, about 15 N / mm 2 More preferably, about 20 N / mm 2 More preferably, about 25 N / mm 2 More than 30N / mm 2 The preferred range of the Martens hardness of the substrate 12b is 8 to 98 N / mm 2 Degree, 8~95N / mm 2 Degree, 8~60N / mm 2 Degree, 8~45N / mm 2 Degree, 8~40N / mm 2 degree, 15~98N / mm2 Degree, 15~95N / mm 2 degree, 15~60N / mm 2 Degree, 15~45N / mm 2 degree, 15~40N / mm 2 degree, 20~98N / mm 2 Degree, 20~95N / mm 2 Degree, 20~60N / mm 2 degree, 20~45N / mm 2 Degree, 20~40N / mm 2 degree, 25~98N / mm 2 Degree, 25~95N / mm 2 degree, 25~60N / mm 2 degree, 25~45N / mm 2 degree, 25~40N / mm 2 degree, 30~98N / mm 2 Degree, 30~95N / mm 2 degree, 30~60N / mm 2 degree, 30~45N / mm 2 degree, 30~40N / mm 2 The degree of

[0042] To further enhance the excellent conformability and bendability of the polyester layer 12a relative to the metal terminal 2, the indentation modulus of the polyester layer 12a measured in a direction perpendicular to the thickness direction of the cross section under the Martens hardness measurement conditions is preferably about 2100 MPa or less, more preferably about 1500 MPa or less, even more preferably about 1200 MPa or less, even more preferably about 1000 MPa or less, and even more preferably about 800 MPa or less. The indentation modulus of the polyester layer 12a is preferably about 400 MPa or more, more preferably about 500 MPa or more, even more preferably about 600 MPa or more, and even more preferably about 700 MPa or more. Preferred ranges for the indentation elastic modulus of the polyester layer 12a include about 400 to 2100 MPa, about 400 to 1500 MPa, about 400 to 1200 MPa, about 400 to 1000 MPa, about 400 to 800 MPa, about 500 to 2100 MPa, about 500 to 1500 MPa, about 500 to 1200 MPa, about 500 to 1000 MPa, about 500 to 800 MPa, about 600 to 2100 MPa, about 600 to 1500 MPa, about 600 to 1200 MPa, about 600 to 1000 MPa, about 600 to 800 MPa, about 700 to 2100 MPa, about 700 to 1500 MPa, about 700 to 1200 MPa, about 700 to 1000 MPa, and about 700 to 800 MPa.

[0043] In order to further preferably exhibit excellent conformability to the metal terminal 2 and excellent bendability, the Martens hardness is measured in the direction perpendicular to the cross section of the polyester layer 12a in the thickness direction under the conditions for measuring the Martens hardness, i.e., an indentation depth h at a load of 10 mN. max is preferably about 2.5 μm or more, more preferably about 2.8 μm or more, and even more preferably about 3.0 μm or more. max The indentation depth h of the polyester layer 12a is preferably about 5.0 μm or less, more preferably about 4.5 μm or less, and even more preferably about 4.0 μm or less. maxPreferred ranges include about 2.5 to 5.0 μm, about 2.5 to 4.5 μm, about 2.5 to 4.0 μm, about 2.8 to 5.0 μm, about 2.8 to 4.5 μm, about 2.8 to 4.0 μm, about 3.0 to 5.0 μm, about 3.0 to 4.5 μm, and about 3.0 to 4.0 μm.

[0044] In order to more suitably exhibit excellent conformability to the metal terminal 2 and excellent bendability, the Martens hardness measured in the direction perpendicular to the cross section in the thickness direction of the substrate 12b under the conditions for measuring the Martens hardness is preferably about 60 N / mm 2 or less, more preferably about 50 N / mm 2 or less, more preferably about 45 N / mm 2 The Martens hardness of the substrate 12b is preferably about 10 N / mm 2 More preferably, about 15 N / mm 2 More preferably, about 20 N / mm 2 More preferably, about 25 N / mm 2 More than 30N / mm 2 The preferred range of the Martens hardness of the substrate 12b is 10 to 60 N / mm 2 Degree, 10~50N / mm 2 Degree, 10~45N / mm 2 degree, 15~60N / mm 2 degree, 15~50N / mm 2 Degree, 15~45N / mm 2 Degree, 20~60N / mm 2 degree, 20~50N / mm 2 degree, 20~45N / mm 2 degree, 25~60N / mm 2 degree, 25~50N / mm 2 degree, 25~45N / mm 2 degree, 30~60N / mm 2 degree, 30~50N / mm 2 degree, 30~45N / mm 2 The degree of

[0045] To further suitably exhibit excellent conformability to the metal terminal 2 and excellent bendability, the indentation modulus of the substrate 12b measured in a direction perpendicular to the thickness cross section under the Martens hardness measurement conditions is preferably about 1500 MPa or less, more preferably about 1200 MPa or less, even more preferably about 1000 MPa or less, and even more preferably about 800 MPa or less. The indentation modulus of the substrate 12b is preferably about 200 MPa or more, more preferably about 300 MPa or more, even more preferably about 500 MPa or more, and even more preferably about 700 MPa or more. Preferred ranges for the indentation elastic modulus of the substrate 12b include about 200 to 1500 MPa, about 200 to 1200 MPa, about 200 to 1000 MPa, about 200 to 800 MPa, about 300 to 1500 MPa, about 300 to 1200 MPa, about 300 to 1000 MPa, about 300 to 800 MPa, about 500 to 1500 MPa, about 500 to 1200 MPa, about 500 to 1000 MPa, about 500 to 800 MPa, about 700 to 1500 MPa, about 700 to 1200 MPa, about 700 to 1000 MPa, and about 700 to 800 MPa.

[0046] In order to further preferably exhibit excellent conformability to the metal terminal 2 and excellent bendability, the Martens hardness is measured in the direction perpendicular to the cross section of the substrate 12b in the thickness direction under the conditions for measuring the Martens hardness, i.e., an indentation depth h at a load of 10 mN. max is preferably about 2.5 μm or more, more preferably about 2.8 μm or more, and even more preferably about 3.0 μm or more. max is preferably about 5.0 μm or less, more preferably about 4.5 μm or less, and even more preferably about 4.0 μm or less. max Preferred ranges include about 2.5 to 5.0 μm, about 2.5 to 4.5 μm, about 2.5 to 4.0 μm, about 2.8 to 5.0 μm, about 2.8 to 4.5 μm, about 2.8 to 4.0 μm, about 3.0 to 5.0 μm, about 3.0 to 4.5 μm, and about 3.0 to 4.0 μm.

[0047] In the adhesive film for metal terminal 1 of the present disclosure, the Martens hardness, the indentation modulus and the indentation depth h of the polyolefin layer 11 and the resin layer 12 (polyester layer 12a, substrate 12b) max These can be adjusted by the composition, skeleton, dispersibility, molecular weight, melting point, MFR of the resin constituting each layer, as well as the conditions of the T-die, inflation, etc. in the production of the adhesive film for metal terminal 1 (for example, the extrusion width from the T-die, the stretching ratio, the stretching speed, the heat treatment temperature, etc.). For example, the Martens hardness, the indentation modulus, and the indentation depth h of the polyolefin layer 11 of the adhesive film for metal terminal max In order to improve flexibility, a method of adjusting the composition of the polyolefin layer 11 includes adding a predetermined amount of a butene component, an ethylene-propylene-butene copolymer, an amorphous ethylene-propylene copolymer, a propylene-α-olefin copolymer, etc. In addition, for example, the Martens hardness, the indentation modulus, and the indentation depth h of the polyester layer 12a of the adhesive film for metal terminals can be adjusted. max As a method for adjusting the composition of the polyester layer 12a, a method of copolymerizing a polyether resin to improve flexibility can be mentioned. In addition, for example, the Martens hardness, indentation modulus and indentation depth h of the substrate 12b of the adhesive film for metal terminal can be adjusted. max As a method for adjusting the composition of the base material 12b, there is a method of copolymerizing polyethylene to improve flexibility.

[0048] The total thickness of the adhesive film 1 for metal terminal of the present disclosure is, for example, about 60 μm or more, preferably about 80 μm or more, preferably about 100 μm or more, more preferably about 120 μm or more, and even more preferably about 150 μm or more, from the viewpoint of more suitably exhibiting excellent conformability to the metal terminal 2 and excellent bendability. The total thickness of the adhesive film 1 for metal terminal of the present disclosure is preferably about 200 μm or less, more preferably 180 μm or less. Preferred ranges for the total thickness of the adhesive film 1 for metal terminal of the present disclosure include about 60 to 200 μm, about 60 to 180 μm, about 80 to 200 μm, about 80 to 180 μm, about 100 to 200 μm, about 100 to 180 μm, about 120 to 200 μm, about 120 to 180 μm, about 150 to 200 μm, and about 150 to 180 μm. As a more specific example, when the adhesive film 1 for metal terminals of the present disclosure is used in a consumer electricity storage device, the total thickness is preferably about 60 to 100 μm, and when it is used in an in-vehicle electricity storage device, the total thickness is preferably about 100 to 200 μm.

[0049] In the adhesive film 1 for metal terminals, the ratio of the total thickness of the polyolefin layer 11 and the resin layer 12 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 packaging material 3 for an electricity storage device of the present disclosure includes the polyolefin layer 11 and the polyester layer 12a, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the packaging material 3 for an electricity storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, when the packaging material 3 for an electricity storage device of the present disclosure includes the polyolefin layer 11, the base material 12b, and the polyester layer 12a, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the packaging material 3 for an electricity storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Furthermore, when the packaging material 3 for an electricity storage device includes the polyolefin layer 11, the adhesion promoter layer 13, the base material 12b, the adhesion promoter layer 13, and the polyester layer 12a, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the packaging material 3 for an electricity storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0050] The polyolefin layer 11 and the resin layer 12 (the polyester layer 12a, the substrate 12b, and the adhesion promoter layer 13) will be described in detail below.

[0051] [Polyolefin layer 11] As shown in Figures 4 and 5, the adhesive film 1 for metal terminals of the present disclosure comprises a polyolefin layer 11 arranged on the metal terminal 2 side and a resin layer 12 arranged on the exterior packaging material 3 for an electricity storage device side.

[0052] In the adhesive film 1 for metal terminals of the present disclosure, the polyolefin layer 11 is a layer containing a polyolefin-based resin. Examples of polyolefin-based resins include polyolefins and acid-modified polyolefins. Among polyolefin-based resins, the polyolefin layer 11 preferably contains an acid-modified polyolefin, and is more preferably a layer formed from an acid-modified polyolefin. Acid-modified polyolefins have a high affinity for metals. Therefore, in the adhesive film 1 for metal terminals of the present disclosure, by arranging the polyolefin layer 11 formed from an acid-modified polyolefin on the metal terminal 2 side, excellent adhesion can be exhibited at the interface between the adhesive film 1 for metal terminals and the metal terminal 2.

[0053] The acid-modified polyolefin is not particularly limited as long as it is an acid-modified polyolefin, but preferred examples include polyolefins graft-modified with an unsaturated carboxylic acid or an anhydride thereof.

[0054] Specific examples of acid-modified 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, polypropylene is more preferred, and homopolypropylene is particularly preferred. That is, it is particularly preferred that the polyolefin layer 11 is formed from acid-modified homopolypropylene.

[0055] The acid-modified polyolefin may be a cyclic polyolefin. For example, a carboxylic acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a cyclic polyolefin by substituting an α,β-unsaturated carboxylic acid or an anhydride thereof for some of the monomers constituting the cyclic polyolefin, or by block polymerizing or graft polymerizing an α,β-unsaturated carboxylic acid or an anhydride thereof with a cyclic polyolefin.

[0056] The acid-modified cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomer constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, preferred are cyclic alkenes, and more preferred are norbornene. Styrene is also an example of a constituting monomer.

[0057] Examples of carboxylic acids or anhydrides thereof used for acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride. When the polyolefin layer 11 is analyzed by infrared spectroscopy, a peak derived from maleic anhydride is preferably detected. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak derived from maleic anhydride is detected at a wave number of 1760 cm. -1 Near and wave number 1780cm -1 A peak derived from maleic anhydride is detected around . When the polyolefin layer 11 is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected when measured by infrared spectroscopy. However, if the degree of acid modification is low, the peak becomes small and may not be detected. In such cases, analysis can be performed by nuclear magnetic resonance spectroscopy.

[0058] The polyolefin layer 11 may be formed of one type of resin component alone, or may be formed of a blend polymer in which two or more types of resin components are combined. Furthermore, the polyolefin layer 11 may be formed of only one layer, or may be formed of two or more layers of the same or different resin components. From the viewpoint of film formability of the polyolefin layer 11, it is preferable to form it of a blend polymer in which two or more types of resin components are combined. When using a blend polymer, the polyolefin layer 11 preferably contains acid-modified polypropylene as the main component (50% by mass or more of a component) and 50% by mass or less of another resin (preferably polyethylene from the viewpoint of improving flexibility). On the other hand, from the viewpoint of the electrolyte resistance of the polyolefin layer 11, it is preferable that the polyolefin layer 11 contains acid-modified polypropylene alone as the resin.

[0059] Furthermore, the polyolefin layer 11 may contain a filler as needed. When the polyolefin layer 11 contains 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 in the range of about 0.1 to 35 μm, preferably about 5.0 to 30 μm, and more preferably about 10 to 25 μm. The content of the filler is in the range of about 5 to 30 parts by mass, and more preferably about 10 to 20 parts by mass, relative to 100 parts by mass of the resin component that forms the polyolefin layer 11.

[0060] 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 component that forms the polyolefin layer 11, a method in which the two are melt-blended in advance using a Banbury mixer or the like to form a masterbatch and then mixed in a predetermined mixing ratio, or a method in which the filler is directly mixed with the resin component can be used.

[0061] Furthermore, each polyolefin layer 11 may contain a pigment, if necessary. Various inorganic pigments can be used as the pigment. A specific example of the pigment is preferably carbon (carbon, graphite), which is exemplified as the filler above. Carbon (carbon, graphite) is a material generally used inside an electricity storage device and is unlikely to dissolve in the electrolyte. Furthermore, it has a significant coloring effect, and a sufficient coloring effect can be obtained with an amount added that does not impair adhesion. Furthermore, it does not melt due to heat, and can increase the apparent melt viscosity of the added resin. Furthermore, it prevents the pressed portion from becoming thin during thermal adhesion (heat sealing), thereby providing excellent sealing between the electricity storage device exterior material and the metal terminal.

[0062] When a pigment is added to the polyolefin layer 11, for example, when carbon black with a particle size of approximately 0.03 μm is used, the amount of pigment added is about 0.05 to 0.3 parts by mass, and preferably about 0.1 to 0.2 parts by mass, per 100 parts by mass of the resin component that forms the polyolefin layer 11. By adding a pigment to the polyolefin layer 11, the presence or absence of the adhesive film for metal terminal 1 can be detected by a sensor or visually inspected.

[0063] The melt mass flow rate (MFR) of the polyolefin layer 11 at 230°C is preferably about 5 g / 10 min or more, more preferably about 7 g / 10 min or more, and even more preferably about 8 g / 10 min or more, from the viewpoint of satisfying the above-mentioned Martens hardness and more suitably exhibiting the excellent conformability and excellent bendability of the adhesive film 1 for metal terminals to the metal terminal 2, and is preferably about 11 g / 10 min or less, more preferably about 10 g / 10 min or less, and preferred ranges include about 5 to 11 g / 10 min, about 5 to 10 g / 10 min, about 7 to 11 g / 10 min, about 7 to 10 g / 10 min, about 8 to 11 g / 10 min, and about 8 to 10 g / 10 min. The melt mass flow rate (MFR) of the polyolefin layer 11 is a value (g / 10 min) measured at 230°C in accordance with the provisions of JIS K7210-1:2014 (ISO 1133-1:2011). When the polyolefin layer 11 is an acid-modified polyolefin layer, it is particularly preferable that the MFR value of the acid-modified polyolefin layer satisfies the above value.

[0064] The melting point of the polyolefin layer 11 is preferably about 120°C or higher, more preferably about 130°C or higher, and is preferably about 160°C or lower, more preferably about 150°C or lower, with preferred ranges being about 120 to 160°C, about 120 to 150°C, about 130 to 160°C, or about 130 to 150°C, from the viewpoint of satisfying the above-mentioned Martens hardness and more preferably exhibiting excellent conformability and bendability of the adhesive film for metal terminal 1 to the metal terminal 2. The melting point is an endothermic peak measured with a differential scanning calorimeter (DSC).

[0065] The thickness of the polyolefin layer 11 is preferably about 10 μm or more, more preferably about 15 μm or more, even more preferably about 20 μm or more, and even more preferably about 30 μm or more, from the viewpoint of satisfying the above-mentioned Martens hardness and more preferably exhibiting the excellent conformability and excellent bendability of the adhesive film 1 for metal terminals to the metal terminal 2, and is, for example, about 120 μm or less, preferably about 80 μm or less, more preferably about 60 μm or less, and even more preferably about 50 μm or less. Preferred ranges for the thickness of the polyolefin layer 11 include about 10 to 120 μm, about 10 to 80 μm, about 10 to 60 μm, about 10 to 50 μm, about 15 to 120 μm, about 15 to 80 μm, about 15 to 60 μm, about 15 to 50 μm, about 20 to 120 μm, about 20 to 80 μm, about 20 to 60 μm, about 20 to 50 μm, about 30 to 120 μm, about 30 to 80 μm, about 30 to 60 μm, and about 30 to 50 μm. More specific examples include, for example, when the adhesive film 1 for metal terminals of the present disclosure is used in a consumer electricity storage device, the thickness of the polyolefin layer 11 is preferably about 10 to 30 μm, and when used in an in-vehicle electricity storage device, it is preferably about 30 to 120 μm.

[0066] The ratio of the thickness of the substrate 12b to the total thickness of the polyolefin layer 11 is preferably about 0.3 or more, more preferably about 0.4 or more, and even more preferably 0.5 or more, from the viewpoint of satisfying the above-mentioned Martens hardness and more preferably exhibiting excellent conformability and excellent bendability of the adhesive film 1 for metal terminals to the metal terminal 2, and is preferably about 1.0 or less, more preferably about 0.8 or less, and preferred ranges include about 0.3 to 1.0, about 0.3 to 0.8, about 0.4 to 1.0, about 0.4 to 0.8, about 0.5 to 1.0, and about 0.5 to 0.8.

[0067] Furthermore, the proportion of the total thickness of the adhesive film for metal terminal 1, taken as 100%, is preferably about 30 to 80%, more preferably about 50 to 70%.

[0068] [Polyester layer 12a] The polyester layer 12a is a layer containing a polyester-based resin.

[0069] Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters. Examples of copolymer polyesters include copolymer polyesters in which ethylene terephthalate is the main repeating unit. Specific examples 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 / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), and polyethylene (terephthalate / decanedicarboxylate). These polyesters may be used alone or in combination of two or more.

[0070] The polyester layer 12a preferably contains at least one of polyethylene terephthalate and polybutylene terephthalate as a resin among polyester-based resins. The resin contained in the polyester layer 12a is preferably at least one of polyethylene terephthalate and polybutylene terephthalate, and more preferably polybutylene terephthalate.

[0071] The polyester layer 12a may be formed of a single resin component alone or a blend polymer of two or more resin components.Furthermore, the polyester layer 12a may be formed of only one layer or two or more layers of the same or different resin components.

[0072] The polyester layer 12a preferably contains a polyester resin and an elastomer. The elastomer contained in the polyester layer 12a may be any elastomer that enhances the flexibility of the adhesive film for metal terminals 1 while ensuring excellent heat resistance and sealing properties. Preferred elastomers include at least one thermoplastic elastomer selected from polyesters, polyamides, polyurethanes, polyolefins, polystyrenes, polyethers, and acrylics, or thermoplastic elastomers that are copolymers of these. More preferred examples include thermoplastic elastomers composed of a block copolymer of polybutylene terephthalate and polyether, and thermoplastic elastomers composed of an α-olefin copolymer of polymethylpentene. In the thermoplastic elastomer composed of a block copolymer of polybutylene terephthalate and polyether, the polyether component may be a copolymer of terephthalic acid and polytetramethylene ether glycol. Specific examples of preferred polyether-based thermoplastic elastomers include polytetramethylene glycol and polyepsilon caprolactam. The content of the elastomer in the polyester layer 12a is not particularly limited as long as it ensures excellent heat resistance and sealing properties of the adhesive film for metal terminal 1 while increasing its flexibility, and is, for example, about 0.1% by mass or more, preferably about 0.5% by mass or more, more preferably about 1.0% by mass or more, and even more preferably about 3.0% by mass or more. The content is, for example, about 10.0% by mass or less, about 8.0% by mass or less, or about 5.0% by mass or less. Preferred ranges for the content include about 0.1 to 10.0 mass%, about 0.1 to 8.0 mass%, about 0.1 to 5.0 mass%, about 0.5 to 10.0 mass%, about 0.5 to 8.0 mass%, about 0.5 to 5.0 mass%, about 1.0 to 10.0 mass%, about 1.0 to 8.0 mass%, about 1.0 to 5.0 mass%, about 3.0 to 10.0 mass%, about 3.0 to 8.0 mass%, and about 3.0 to 5.0 mass%, etc.

[0073] From the viewpoint of improving the heat resistance of the adhesive film for metal terminal 1, the melting point of the polyester layer 12a is preferably at least 20°C higher, more preferably at least 40°C higher, and even more preferably at least 60°C higher than the melting point of the polyolefin layer 11. The melting point of the polyester layer 12a is preferably at least 180°C, more preferably at least 190°C, and even more preferably at least 200°C, and is preferably at most 240°C, more preferably at most 230°C, and even more preferably at most 220°C.

[0074] To more suitably achieve the effects of the present disclosure, the thickness of the polyester layer 12a is preferably about 10 μm or more, more preferably about 15 μm or more, and even more preferably about 20 μm or more, and is preferably about 60 μm or less, more preferably about 55 μm or less, and even more preferably about 50 μm or less. Preferred thickness ranges for the polyester layer 12a include about 10 to 60 μm, about 10 to 55 μm, about 10 to 50 μm, about 15 to 60 μm, about 15 to 55 μm, about 15 to 50 μm, about 20 to 60 μm, about 20 to 55 μm, and about 20 to 50 μm, respectively.

[0075] In the present disclosure, from the viewpoint of more suitably exerting the effects of the present disclosure, the ratio of the thickness of the polyester layer 12a to the total thickness (100%) of the adhesive film 1 for metal terminals is preferably 20% or more, more preferably 30% or more, even more preferably 40% or more, and also preferably 80% or less, more preferably 70% or less, even more preferably 60% or less.

[0076] [Base material 12b] In the adhesive film 1 for a metal terminal, the substrate 12b is a layer that functions as a support for the adhesive film 1 for a metal terminal.

[0077] The material forming the substrate 12b is not particularly limited. Examples of materials that can be used to form the substrate 12b 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 12b is preferably a resin containing a polyolefin skeleton, such as polyolefin or acid-modified polyolefin. Whether the resin forming the substrate 12b contains a polyolefin skeleton can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like.

[0078] As described above, the substrate 12b preferably contains a polyolefin resin, more preferably a polyolefin, and more preferably a layer formed of a polyolefin. 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. In particular, from the viewpoints of increasing the residual thickness of the adhesive film for metal terminals after heat sealing and imparting excellent insulating properties to the adhesive film for metal terminals, the substrate 12b preferably contains homopolypropylene, and is particularly preferably formed of homopolypropylene.

[0079] 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.

[0080] 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.

[0081] Furthermore, the base material 12b may be formed of a nonwoven fabric made of the above-mentioned resin. When the base material 12b is a nonwoven fabric, the base material 12b is preferably made of the above-mentioned polyolefin resin, polyamide resin, or the like.

[0082] Furthermore, by blending a colorant into the substrate 12b, the substrate 12b can be made into a layer containing a colorant. Also, light transmittance can be adjusted by selecting a resin with low transparency. When the substrate 12b is a film, a colored film or a film with low transparency can be used. When the substrate 12b is a nonwoven fabric, a nonwoven fabric using fibers or a binder containing a colorant or a nonwoven fabric with low transparency can be used.

[0083] The melt mass flow rate (MFR) of the substrate 12b at 230°C is preferably 8g / 10min or less, more preferably 4g / 10min or less, from the viewpoint of satisfying the above-mentioned Martens hardness and more preferably exhibiting excellent conformability and bendability of the adhesive film 1 for metal terminal 2. Also, from the viewpoint of obtaining an adhesive film 1 for metal terminal 1 with excellent flexibility (good evaluation of conformability and bendability, described below), it is preferably 1g / 10min or more, more preferably 2g / 10min or more, with preferred ranges being about 1 to 8g / 10min, about 1 to 4g / 10min, about 2 to 8g / 10min, and about 2 to 4g / 10min. When the substrate 12b is a polyolefin layer (a layer formed from polyolefin), it is particularly suitable that the MFR value of the polyolefin layer satisfies the above values. The melt mass flow rate (MFR) of the substrate 12b is a value (g / 10 min) at 230° C. measured in accordance with the provisions of JIS K7210-1:2014 (ISO 1133-1:2011).

[0084] Furthermore, from the viewpoint of satisfying the above-mentioned Martens hardness and more preferably exhibiting excellent conformability and bendability of the adhesive film for metal terminal 1 to the metal terminal 2, the melting point of the substrate 12b is preferably 130°C or higher, more preferably 150°C or higher, and is preferably 190°C or lower, more preferably 170°C or lower, with preferred ranges being about 130 to 190°C, about 130 to 170°C, about 150 to 190°C, or about 150 to 170°C. The melting point is an endothermic peak measured with a differential scanning calorimeter (DSC).

[0085] When the substrate 12b is made of a resin film, the surface of the substrate 12b may be subjected to a known adhesion enhancing treatment such as corona discharge treatment, ozone treatment, or plasma treatment, if necessary.

[0086] The thickness of the substrate 12b is, for example, about 100 μm or less, preferably about 60 μm or less, and more preferably about 55 μm or less, from the viewpoint of more suitably exhibiting the excellent conformability and bendability of the adhesive film for a metal terminal 1 to the metal terminal 2. The thickness of the substrate 12b is preferably about 20 μm or more, more preferably about 30 μm or more, and even more preferably about 40 μm or more. Preferred ranges for the thickness of the substrate 12b include about 20 to 100 μm, about 20 to 60 μm, about 20 to 55 μm, about 30 to 100 μm, about 30 to 60 μm, about 30 to 55 μm, about 40 to 100 μm, about 40 to 60 μm, and about 40 to 55 μm. As a more specific example, when the adhesive film 1 for metal terminals of the present disclosure is used in a consumer electricity storage device, the thickness of the substrate 12b is preferably about 30 to 55 μm, and when used in an in-vehicle electricity storage device, the thickness is preferably about 40 to 100 μm.

[0087] [Adhesion promoter layer 13] The adhesion promoter layer 13 is a layer that is provided as needed for the purpose of firmly adhering the substrate 12b to the polyolefin layer 11 and the polyester layer 12a (see FIG. 5). The adhesion promoter layer 13 may be provided on only one side between the substrate 12b and the polyolefin layer 11 and the polyester layer 12a, or on both sides.

[0088] 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 further improving electrolyte resistance, 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 show little decrease in laminate strength after immersion in an electrolyte. 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.

[0089] 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 2 In the case of a two-component curing adhesion promoter that uses polyethyleneimine as the main component and polycarbodiimide as the crosslinking agent, the adhesive strength is about 5 to 50 mg / m 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:

[0090] [ka]

[0091] The adhesive film for metal terminal 1 of the present disclosure can be produced, for example, by laminating a polyolefin layer 11 and a polyester layer 12a on both surfaces of a substrate 12b. The substrate 12b and the polyolefin layer 11 and the polyester layer 12a can be laminated by known methods such as extrusion lamination, T-die lamination, inflation lamination, and thermal lamination. When the substrate 12b and the polyolefin layer 11 and the polyester layer 12a are laminated via an adhesion promoter layer 13, for example, the adhesion promoter that constitutes the adhesion promoter layer 13 can be applied to the substrate 12b by the above-mentioned method and dried, and then the polyolefin layer 11 and the polyester layer 12a can be laminated on top of the adhesion promoter layer 13.

[0092] 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.

[0093] [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.

[0094] 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.

[0095] 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 4000 μm, more preferably about 60 to 3000 μm, and even more preferably about 70 to 1000 μm. The length of the metal terminal 2 is preferably about 1 to 200 mm, and more preferably about 3 to 150 mm. The width of the metal terminal 2 is preferably about 1 to 200 mm, and more preferably about 3 to 150 mm.

[0096] [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. 6 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 periphery 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.

[0097] The thickness of the laminate constituting the electricity storage device packaging material 3 is not particularly limited, but the upper limit, from the viewpoints of cost reduction, energy density improvement, etc., is preferably about 190 μm or less, about 180 μm or less, about 160 μm or less, about 155 μm or less, about 140 μm or less, about 130 μm or less, or about 120 μm or less, and the lower limit, from the viewpoint of maintaining the function of the electricity storage device packaging material 3 to protect the electricity storage device elements 4, is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, or about 80 μm or more, and preferred ranges are, for example, about 35 to 190 μm, about 35 to 180 μm, or about 35 to 160 μm. , about 35-155μm, about 35-140μm, about 35-130μm, about 35-120μm, about 45-190μm, about 45-180μm, 45- Approx. 160μm, approx. 45~155μm, approx. 45~140μm, approx. 45~130μm, approx. 45~120μm, approx. 60~190μm, 60~180μm Examples include about 60 to 160 μm, about 60 to 155 μm, about 60 to 140 μm, about 60 to 130 μm, about 60 to 120 μm, about 80 to 190 μm, about 80 to 180 μm, about 80 to 160 μm, about 80 to 155 μm, about 80 to 140 μm, about 80 to 130 μm, and about 80 to 120 μm.

[0098] Furthermore, the adhesive film 1 for metal terminals of the present disclosure can be suitably applied to packaging materials for all-solid-state batteries, and the thickness of the laminate constituting the packaging material for all-solid-state batteries is not particularly limited, but from the viewpoints of cost reduction, improving energy density, etc., it is preferably about 10,000 μm or less, about 8,000 μm or less, about 5,000 μm or less, and about 500 μm or less. From the viewpoint of maintaining the function of the packaging material for all-solid-state batteries, which is to protect the battery element, it is preferably about 100 μm or more, about 1 Examples of the thickness include 50 μm or more and approximately 200 μm or more, and preferred ranges include, for example, about 100 to 10,000 μm, about 100 to 8,000 μm, about 100 to 5,000 μm, about 150 to 10,000 μm, about 150 to 8,000 μm, about 150 to 5,000 μm, about 200 to 10,000 μm, about 200 to 8,000 μm, about 200 to 5,000 μm, about 150 to 500 μm, and about 200 to 500 μm, with about 100 to 500 μm being particularly preferred.

[0099] (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.

[0100] 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, 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] The thickness of the base layer 31 is, for example, about 10 to 50 μm, and preferably about 15 to 30 μm.

[0106] (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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] Furthermore, when the packaging material 3 for an electricity storage device is a packaging material for an all-solid-state battery, the adhesive layer 32 is preferably formed from a cured product of a resin composition containing at least one of polyester and polycarbonate and at least one of an alicyclic isocyanate compound and an aromatic isocyanate compound. This prevents delamination between the barrier layer 33 and the heat-fusible resin layer 35 in a high-temperature environment, and also enables the packaging material for an all-solid-state battery to exhibit high seal strength.

[0111] The polyester is preferably a polyester polyol. There are no particular limitations on the polyester polyol as long as it has an ester bond in the polymer main chain and a plurality of hydroxyl groups at the terminal or side chain. The polycarbonate is preferably a polycarbonate polyol. There are no particular limitations on the polyester polyol as long as it has a carbonate bond in the polymer main chain and a plurality of hydroxyl groups at the terminal or side chain. The polyester is preferably, for example, a polyester obtained by previously reacting a polyester polyol with a polyisocyanate (e.g., diisocyanate) to extend the urethane chain, or a polycarbonate obtained by previously reacting a polycarbonate polyol with a polyisocyanate (e.g., diisocyanate) to extend the urethane chain. The polyester and polycarbonate contained in the resin composition forming the adhesive layer 5 may each be one type or two or more types.

[0112] The alicyclic isocyanate compound is not particularly limited as long as it is a compound having an alicyclic structure and an isocyanate group. The alicyclic isocyanate compound preferably has two or more isocyanate groups. Specific examples of the alicyclic isocyanate compound include isophorone diisocyanate (IPDI), bis(4-isocyanatocyclohexyl)methane, 1,3-bis(isocyanatomethyl)cyclohexane, methylenebis(4,1-cyclohexylene)diisocyanate, and the like, as well as their polymers or nurates, mixtures thereof, and copolymers with other polymers. Other examples include adducts, biuret compounds, and isocyanurates. The alicyclic isocyanate compound is preferably a polyol-modified polyisocyanate obtained by reacting an alicyclic isocyanate with a polyol (e.g., polyester polyol) in advance. The resin composition forming the adhesive layer 5 may contain one or more types of alicyclic isocyanate compounds.

[0113] The aromatic isocyanate compound is not particularly limited as long as it is a compound having an aromatic ring and an isocyanate group. Preferably, the aromatic isocyanate compound has two or more isocyanate groups. Specific examples of aromatic isocyanate compounds include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), their polymers or nurates, mixtures of these, and copolymers with other polymers. Other examples include adducts, biuret compounds, and isocyanurates. Preferably, the aromatic isocyanate compound is a polyol-modified polyisocyanate obtained by reacting an aromatic isocyanate with a polyol (e.g., polyester polyol) in advance. The aromatic isocyanate compound contained in the resin composition forming the adhesive layer 5 may be one type or two or more types.

[0114] The resin composition forming the adhesive layer 32 may, for example, contain an alicyclic isocyanate compound but not contain an aromatic isocyanate compound, or may, for example, contain an aromatic isocyanate compound but not contain an alicyclic isocyanate compound, or may, for example, contain both an alicyclic isocyanate compound and an aromatic isocyanate compound. The resin composition forming the adhesive layer 32 preferably contains an aromatic isocyanate compound.

[0115] The content of the alicyclic isocyanate compound and aromatic isocyanate compound in the adhesive layer 32 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %, in the resin composition constituting the adhesive layer 5. Furthermore, when the adhesive layer 5 contains both an alicyclic isocyanate compound and an aromatic isocyanate compound, the total content thereof in the resin composition constituting the adhesive layer 5 is preferably in the range of 0.1 to 50 mass %, and more preferably in the range of 0.5 to 40 mass %.

[0116] The thickness of the adhesive layer 32 is, for example, about 2 to 50 μm, and preferably about 3 to 25 μm.

[0117] (Barrier layer 33) In the electrical storage device packaging material, the barrier layer 33 is a layer that not only improves the strength of the electrical storage device packaging material but also has the function of preventing water vapor, oxygen, light, and the like from penetrating into the electrical storage device. The barrier layer 33 is preferably a metal layer, i.e., a layer formed of a metal. Specific examples of metals constituting the barrier layer 33 include aluminum, stainless steel, and titanium, and aluminum is preferred. The barrier layer 33 can be formed, for example, from a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, or a film provided with any of these vapor deposition films. It is preferably formed from a metal foil, and more preferably from an aluminum foil. From the viewpoint of preventing the occurrence of wrinkles or pinholes in the barrier layer 33 during the production of the 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).

[0118] The thickness of the barrier layer 33 is preferably about 10 to 200 μm, and more preferably about 20 to 100 μm, from the viewpoint of making the packaging material for an electricity storage device thinner and making it less likely to produce pinholes during molding.

[0119] 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.

[0120] (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.

[0121] The adhesive layer 34 is formed of an adhesive capable of bonding the barrier layer 33 and the heat-sealable resin layer 35. The composition of the adhesive used to form the adhesive layer is not particularly limited, but examples thereof include a resin composition containing an acid-modified polyolefin. Examples of acid-modified polyolefins include the same as those exemplified for the polyolefin layer 11.

[0122] It is also preferable that the adhesive layer 34 is a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group, and it is particularly preferable that the adhesive layer 34 is a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group.

[0123] Furthermore, when the packaging material 3 for an electricity storage device is a packaging material for an all-solid-state battery, similar to the adhesive layer 32, the adhesive layer 34 is preferably formed from a cured product of a resin composition containing at least one of polyester and polycarbonate, and at least one of an alicyclic isocyanate compound and an aromatic isocyanate compound.

[0124] The thickness of the adhesive layer 34 is, for example, about 1 to 40 μm, and preferably about 2 to 30 μm.

[0125] (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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] The heat-sealable resin layer 35 may be formed of a single resin component alone, or may be formed of a blend polymer of two or more resin components. The heat-sealable resin layer 35 may be formed of only one layer, or may be formed of two or more layers of the same or different resin components. It is particularly preferred that the polyester layer 12a and the heat-sealable resin layer 35 use the same resin, as this improves adhesion between these layers.

[0131] The thickness of the heat-fusible 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.

[0132] Furthermore, the adhesive film 1 for metal terminals of the present disclosure can be particularly suitably applied to packaging materials for all-solid-state batteries, and the melting point of the heat-sealable resin layer 35 of the packaging material for all-solid-state batteries is preferably 150 to 250°C, more preferably 180 to 270°C, even more preferably 200 to 270°C, and even more preferably 200 to 250°C.

[0133] Examples of resins contained in the heat-sealable resin layer 35 of the all-solid-state battery packaging material include polyolefins such as polypropylene and polyethylene, acid-modified polyolefins such as acid-modified polypropylene and acid-modified polyethylene, and polybutylene terephthalate. Among these, polybutylene terephthalate has excellent heat resistance, so in the all-solid-state battery packaging material, the heat-sealable resin layer 35 is preferably formed from a polybutylene terephthalate film. Furthermore, by forming the heat-sealable resin layer 35 from a polybutylene terephthalate film, adhesion to the resin layer of the adhesive film for metal terminal of the present disclosure is also excellent. The polybutylene terephthalate film forming the heat-sealable resin layer 35 may be formed by laminating a pre-prepared polybutylene terephthalate film with the adhesive layer 34 to form the heat-sealable resin layer 35, or by melt-extruding the resin forming the polybutylene terephthalate film to form a film and laminating it with the adhesive layer 34, or by co-extruding the adhesive layer 34 and the polybutylene terephthalate and laminating it on the barrier layer 33.

[0134] The polybutylene terephthalate film may be a stretched polybutylene terephthalate film or an unstretched polybutylene terephthalate film, and is preferably an unstretched polybutylene terephthalate film.

[0135] The polybutylene terephthalate film preferably further contains an elastomer in addition to polybutylene terephthalate. The elastomer serves to ensure the durability of the polybutylene terephthalate film in high-temperature environments while increasing its flexibility. Preferred elastomers include at least one thermoplastic elastomer selected from polyesters, polyamides, polyurethanes, polyolefins, polystyrenes, and polyethers, or thermoplastic elastomer copolymers thereof. The content of the elastomer in the polybutylene terephthalate film is not particularly limited as long as it ensures the durability of the polybutylene terephthalate film in high-temperature environments while increasing its flexibility. For example, the content is about 0.1% by mass or more, preferably about 0.5% by mass or more, more preferably about 1.0% by mass or more, and even more preferably about 3.0% by mass or more. The content may be, for example, about 10.0% by mass or less, about 8.0% by mass or less, or about 5.0% by mass or less. Preferred ranges for the content include about 0.1 to 10.0 mass%, about 0.1 to 8.0 mass%, about 0.1 to 5.0 mass%, about 0.5 to 10.0 mass%, about 0.5 to 8.0 mass%, about 0.5 to 5.0 mass%, about 1.0 to 10.0 mass%, about 1.0 to 8.0 mass%, about 1.0 to 5.0 mass%, about 3.0 to 10.0 mass%, about 3.0 to 8.0 mass%, and about 3.0 to 5.0 mass%, etc.

[0136] 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 resins. When the heat-sealable resin layer 35 is formed of two or more layers, at least one layer is formed of a polybutylene terephthalate film, and the polybutylene terephthalate film is preferably the innermost layer of the all-solid-state battery packaging material. Furthermore, the layer bonded to the adhesive layer 34 is preferably a polybutylene terephthalate film. When the heat-sealable resin layer 35 is formed of two or more layers, the layer not formed of a polybutylene terephthalate film may be formed of, for example, a polyolefin such as polypropylene or polyethylene, or an acid-modified polyolefin such as acid-modified polypropylene or acid-modified polyethylene. However, since polyolefins and acid-modified polyolefins have lower durability in high-temperature environments than polybutylene terephthalate, the heat-sealable resin layer 35 is preferably formed of only a polybutylene terephthalate film.

[0137] 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.

[0138] Specifically, an electricity storage device element 4 including at least a positive electrode, a negative electrode, and an electrolyte is enclosed in an electricity storage device packaging material 3, with metal terminals 2 connected to the positive and negative electrodes protruding outward, and an adhesive film 1 for metal terminals of the present disclosure is interposed between the metal terminals 2 and a heat-sealable resin layer 35, and the electricity storage device element 4 is covered around its periphery so as to form a flange portion of the electricity storage device packaging material (a region where the heat-sealable resin layers 35 come into contact with each other, i.e., the peripheral portion 3a of the electricity storage device packaging material), and the heat-sealable resin layers 35 of the flange portion are heat-sealed to provide an electricity storage device 10 using the electricity storage device packaging material 3. When the electricity storage device element 4 is housed using the electricity storage device packaging material 3, the heat-sealable resin layer 35 of the electricity storage device packaging material 3 is used so that it faces inside (the surface in contact with the electricity storage device element 4).

[0139] The exterior material for an electricity storage device according to 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 according to 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 according to the present disclosure is applied is not particularly limited, and examples include lithium ion batteries, lithium ion polymer batteries, all-solid-state 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 according to the present disclosure.

[0140] Among these, the adhesive film for metal terminal 1 of the present disclosure can be suitably applied to all-solid-state batteries. [Example]

[0141] 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.

[0142] <Production of adhesive film for metal terminals> Example 1 A laminate was produced by coextrusion molding in which a maleic anhydride-modified polypropylene (polypropylene modified with maleic anhydride) forming a polyolefin-based resin layer, an imine-modified polypropylene (polypropylene modified with a basic functional group (IP: imine-modified PP)) forming a polyolefin-based resin layer, and a polybutylene terephthalate forming a polyester-based resin layer were laminated in this order, and a polyolefin-based resin layer (h-PPa layer, thickness 30 μm) / an imine-modified polyolefin-based resin layer (r-IP layer, thickness 30 μm) / a polyester-based resin layer (h-PBT layer, thickness 40 μm) were laminated in this order to obtain an adhesive film for metal terminals (thickness 100 μm). The materials forming the polyolefin layer, polyester layer, and base layer were particularly flexible materials not used in conventional adhesive films for metal terminals, so that they had the Martens hardness listed in Table 1.

[0143] Example 2 A laminate was produced by coextrusion molding in which a maleic anhydride-modified polypropylene (polypropylene modified with maleic anhydride) forming a polyolefin-based resin layer, an imine-modified polypropylene (polypropylene modified with a basic functional group (IP: imine-modified PP)) forming a polyolefin-based resin layer, and a polybutylene terephthalate forming a polyester-based resin layer were laminated in this order, and a polyolefin-based resin layer (h-PPa layer, thickness 30 μm) / an imine-modified polyolefin-based resin layer (h-IP layer, thickness 30 μm) / a polyester-based resin layer (h-PBT layer, thickness 40 μm) were laminated in this order to obtain an adhesive film for metal terminals (thickness 100 μm). The materials forming the polyolefin layer, polyester layer, and base layer were particularly flexible materials not used in conventional adhesive films for metal terminals, so that they had the Martens hardness listed in Table 1.

[0144] Example 3 A laminate was produced by coextrusion molding in which a maleic anhydride-modified polypropylene (polypropylene modified with maleic anhydride) forming a polyolefin-based resin layer, an imine-modified polypropylene (polypropylene modified with a basic functional group (IP: imine-modified PP)) forming a polyolefin-based resin layer, and a polybutylene terephthalate forming a polyester-based resin layer were laminated in this order. A polyolefin-based resin layer (h-PPa layer, 30 μm thick) / an imine-modified polyolefin-based resin layer (r-IP layer, 30 μm thick) / a polyester-based resin layer (copolymerized with polyether-PBT layer, 40 μm thick) were laminated in this order to obtain an adhesive film for metal terminals (100 μm thick). The materials forming the polyolefin layer, polyester layer, and base layer were particularly flexible materials not used in conventional adhesive films for metal terminals, so that they had the Martens hardness listed in Table 1.

[0145] Example 4 A laminate was produced by coextrusion molding in which a maleic anhydride-modified polypropylene (polypropylene modified with maleic anhydride) forming a polyolefin-based resin layer, an imine-modified polypropylene (polypropylene modified with a basic functional group (IP: imine-modified PP)) forming a polyolefin-based resin layer, and a polybutylene terephthalate forming a polyester-based resin layer were laminated in this order. A polyolefin-based resin layer (h-PPa layer, 30 μm thick) / an imine-modified polyolefin-based resin layer (h-IP layer, 30 μm thick) / a polyester-based resin layer (copolymerized with polyether-PBT layer, 40 μm thick) were laminated in this order to obtain an adhesive film for metal terminals (100 μm thick). The materials forming the polyolefin layer, polyester layer, and base layer were particularly flexible materials not used in conventional adhesive films for metal terminals, so that they had the Martens hardness listed in Table 1.

[0146] Example 5 A laminate was produced by coextrusion molding in which a maleic anhydride-modified polypropylene (h-PPa, different from those used in Examples 1-4) forming the polyolefin resin layer, an imine-modified polypropylene (polypropylene modified with a basic functional group (IP: imine-modified PP)) forming the polyolefin resin layer, and a polybutylene terephthalate (the same as in Examples 3 and 4) forming the polyester resin layer were laminated in this order. A 100 μm thick adhesive film for metal terminals was obtained, in which the polyolefin resin layer (h-PPa layer, 30 μm thick) / imine-modified polyolefin resin layer (h-IP layer, 30 μm thick) / polyester resin layer (copolymerized with polyether-PBT layer, 40 μm thick) were laminated in this order. The materials forming the polyolefin layer, polyester layer, and base layer were particularly flexible materials not used in conventional adhesive films for metal terminals, so as to have the Martens hardness listed in Table 1.

[0147] Example 6 The polyolefin layers on the metal terminal side and the exterior material side for the power storage device were made of maleic anhydride-modified random polypropylene (r-PPa), and the base material was made of random polypropylene (r-PP). Using the resins for each layer, T-die extrusion molding was performed to obtain an adhesive film for metal terminals (100 μm) consisting of a polyolefin layer (25 μm, r-PPa layer), a base material (100 μm, r-PP layer), and a resin layer (25 μm, r-PPa layer) laminated in that order.

[0148] Comparative Example 1 A laminate was produced by coextrusion molding in which a maleic anhydride-modified polypropylene (h-PPa, different from Examples 1-5) forming a polyolefin-based resin layer, an imine-modified polypropylene (same as Examples 2, 4, and 5) forming a polyolefin-based resin layer, and a polybutylene terephthalate forming a polyester-based resin layer (different from Examples 1 and 2) were laminated in this order, and an adhesive film for metal terminals (100 μm thick) was obtained in which a polyolefin-based resin layer (h-PPa layer, 30 μm thick) / an imine-modified polyolefin-based resin layer (h-IP layer, 30 μm thick) / a polyester-based resin layer (copolymerized with polyether-PBT layer, 40 μm thick) were laminated in this order. Materials forming the polyolefin layer, polyester layer, and base layer were used that were particularly flexible and not used in conventional adhesive films for metal terminals, so as to have the Martens hardness listed in Table 1.

[0149] Comparative Example 2 A laminate was produced by coextrusion molding in which a maleic anhydride-modified polypropylene (h-PPa, different from Examples 1-5) forming a polyolefin-based resin layer, an imine-modified polypropylene (same as in Examples 2, 4, and 5) forming a polyolefin-based resin layer, and a polybutylene terephthalate (same as in Examples 3, 4, and 5) forming a polyester-based resin layer were laminated in this order, and an adhesive film for metal terminals (thickness 100 μm) was obtained in which a polyolefin-based resin layer (h-PPa layer, thickness 30 μm) / an imine-modified polyolefin-based resin layer (h-IP layer, thickness 30 μm) / a polyester-based resin layer (copolymerized with polyether-PBT layer, thickness 40 μm) were laminated in this order. The materials forming the polyolefin layer, polyester layer, and base layer were particularly flexible materials not used in conventional adhesive films for metal terminals, so that they had the Martens hardness listed in Table 1.

[0150] <Martens hardness, indentation modulus, indentation depth h max Measurement of The Martens hardness, indentation modulus and indentation depth h of the polyolefin layer, substrate and resin layer of the adhesive film for metal terminals in the examples and comparative examples were measured. max These measurements were performed by cutting the adhesive film for metal terminals to 30 mm in MD and 15 mm in TD as a pretreatment for the samples to be measured. Next, the samples were embedded in an epoxy cold mounting resin and allowed to dry for approximately one day. The cross-section obtained by cutting in the TD direction was then polished using a Tegrapol-35 mechanical polishing machine manufactured by Marumoto Struers, resulting in a surface roughness of approximately 1.0 μm. Measurements were performed using the indentation method using a Picodentor HM-500 manufactured by Fisher Instruments, with measurements being performed in the direction perpendicular to the cross-section in the thickness direction of the layer to be measured (the center part in the thickness direction). The cross-section to be measured was obtained by cutting the adhesive film for metal terminals in the TD direction and was subjected to the pretreatment described above. The measurement conditions were as follows. (Measurement conditions) The applied load is 10 mN. The load application rate is 1 mN / 10 seconds. The holding time is 10 seconds. The loading and unloading rate is 1 mN / 10 seconds. The indenter is a Vickers indenter with a square pyramid-shaped tip with an opposing angle of 136°. The measurement temperature is 25°C. The measurement values ​​were measured 10 times at different measurement locations, and the average value of a total of eight measurement values ​​was calculated, excluding one maximum value and one minimum value.

[0151] For reference, the Martens hardness, indentation modulus, and indentation depth h max FIG. 8 shows an image of a graph showing the relationship between the indentation depth (μm) and the load (mN) obtained by the measurement.

[0152] The Martens hardness is calculated by the following formula: HM (Martens hardness) = Maximum load F (N) / Surface area of ​​indenter calculated from indentation depth (mm 2 )=Maximum load F(N) / 26.43h2 F: Maximum load (N) h: Indentation depth under test load = h max (The value at point E in Figure 8 (the point where a perpendicular line is drawn from point C to the Y axis))

[0153] The indentation modulus is calculated from the gradient of the tangent line of CD in Figure 8. max is calculated from the value at point E in Figure 8.

[0154] <Conformity evaluation (adhesive film / metal terminal)> An aluminum foil (JIS H4160:1994 A8079H-O) measuring 50 mm in length, 22.5 mm in width, and 400 μm in thickness was prepared as a metal terminal. Each adhesive film for metal terminals (45 mm in length and 15 mm in width) obtained in the Examples and Comparative Examples was also prepared. Next, the metal terminal was sandwiched between two adhesive films to obtain an adhesive film / metal terminal / adhesive film laminate. The two films were overlapped so that the longitudinal direction of the metal terminal and the width direction of the adhesive film for metal terminal coincided, with the overlapping area measuring 22.5 mm x 15 mm. Next, the laminate sandwiched between two tetrafluoroethylene-ethylene copolymer films (ETFE films, 100 μm thick) was placed on a hot plate heated to 190°C, and a 500 g weight with a sponge attached was placed on top (pressure of 0.015 MPa). The laminate was then left to stand for 12 seconds to heat-seal the adhesive film to the metal terminal. At this time, as shown in the schematic diagram of Figure 7, the metal terminal was sandwiched between the adhesive films, so that the metal terminal was surrounded by the adhesive film and a portion where the two adhesive films were heat-sealed together was formed. The heat-sealed laminate was allowed to cool naturally to 25°C, and a cross section in the thickness direction (see area M surrounded by the dashed circle in Figure 7) was observed with a laser microscope to evaluate the conformability of the adhesive film for metal terminals to the shape of the metal terminal according to the following criteria. The results are shown in Table 1. A+: No air bubbles between the adhesive film for metal terminals and the metal terminals A: There are no bubbles at the interface between the adhesive film for metal terminals and the metal terminal, but there are bubbles in the adhesive film for metal terminals near the interface. B: There are bubbles at the interface between the adhesive film for metal terminals and the metal terminal, but there are no bubbles in the adhesive film for metal terminals near the interface. C: There are bubbles at the interface between the adhesive film for metal terminals and the metal terminals, and there are also bubbles in the adhesive film for metal terminals near the interface.

[0155] <Bending property evaluation> Each adhesive film for metal terminals obtained in the Examples and Comparative Examples was cut to a size of 100 mm in length (MD) and 15 mm in width (TD). The adhesive film was wrapped around a mandrel testing machine (a metal rod with a diameter of 2 mm) and subjected to a bending test. The adhesive film for metal terminals was visually observed and evaluated according to the following criteria. The results are shown in Table 1. A+: The adhesive film for metal terminals does not whiten on the wrapped area, and returns to its original shape after wrapping. A: There is no whitening of the area where the adhesive film for metal terminals is wrapped, but it does not return to its original shape after wrapping and tends to curl slightly. B: There is no whitening in the area where the adhesive film for metal terminals is wrapped, but it does not return to its original shape after wrapping and curls. C: Whitening of the area where the adhesive film for metal terminals is wrapped

[0156] <Insulation evaluation (measurement of remaining thickness of adhesive film for metal terminals after heat sealing)> The center of the adhesive film for metal terminals of the metal terminals with adhesive film for metal terminals obtained in Examples and Comparative Examples was cut, and the thickness of the adhesive film for metal terminals was measured by cross-sectional observation under an optical microscope and recorded as the pre-sealing thickness. Next, the exterior packaging material was cut to a size of 60 x 150 mm, folded in half with the heat-sealable resin layer on the inside, and a separately prepared metal terminal with adhesive film for metal terminals was sandwiched between the two pieces with the edge closest to the adhesive film for metal terminals pressed against the fold. The metal terminal was heat-sealed using a 7 mm wide upper and lower metal head sealer under conditions of 240°C x 1.0 MPa x 5 seconds. The center of this sealed portion was cut, and the thickness of the adhesive film for metal terminals was measured in the same manner as the pre-sealing thickness and recorded as the post-sealing thickness. The remaining percentage of the adhesive film for metal terminals (%) was calculated from the post-sealing thickness / pre-sealing thickness (minus the thickness of the metal terminal) and used to evaluate insulation properties. The results are shown in Table 1.

[0157] [Table 1]

[0158] In the layer configurations shown in Table 1, h-PPa means homopolypropylene modified with maleic anhydride, r-PPa means random polypropylene modified with maleic anhydride, h-IP means imine-modified homopolypropylene, r-IP means imine-modified random polypropylene, and h-PBT means homopolybutylene terephthalate, and the numbers in parentheses indicate the thickness (μm).

[0159] The adhesive film for metal terminals of Example 1-5 had a Martens hardness of 37 N / mm2 measured in a direction perpendicular to the cross section in the thickness direction of the polyolefin layer. 2 and the Martens hardness measured in the direction perpendicular to the cross section in the thickness direction of the resin is 98 N / mm 2 (In Examples 1 to 5, the Martens hardness measured in the direction perpendicular to the cross section of the substrate and polyester layer, which are resin layers, is 98 N / mm 2The adhesive films for metal terminals of Examples 1-5 are excellent in conformability to the shape of the metal terminal during heat sealing, and are also excellent in bendability.

[0160] 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 a metal terminal is composed of a laminate including, in this order, at least a polyolefin layer disposed on the metal terminal side and a resin layer disposed on the exterior material for an electricity storage device side; The polyolefin layer has a Martens hardness of 37 N / mm when measured in a direction perpendicular to a cross section in the thickness direction of the polyolefin layer under the following measurement conditions: 2 is as follows: The resin layer has a Martens hardness of 98 N / mm when measured in a direction perpendicular to a cross section in the thickness direction of the resin layer under the following measurement conditions: 2 An adhesive film for a metal terminal, comprising the following layers: <Measurement conditions for Martens hardness> The applied load is 10 mN. The load application rate is 1 mN / 10 seconds. The holding time is 10 seconds. The loading and unloading rate is 1 mN / 10 seconds. The indenter is a Vickers indenter with a square pyramid-shaped tip with an opposing angle of 136°. The measurement temperature is 25°C. The measurement values ​​were measured 10 times at different measurement locations, and the average value of a total of eight measurement values ​​was calculated, excluding one maximum value and one minimum value. Item 2. An adhesive film for metal terminals according to Item 1, wherein the indentation modulus measured in a direction perpendicular to a cross section in the thickness direction of the polyolefin layer under the conditions for measuring the Martens hardness is 700 MPa or less. Item 3. The adhesive film for metal terminal according to Item 1 or 2, wherein the polyolefin layer has a thickness of 120 μm or less. Item 4. Under the conditions for measuring the Martens hardness, the indentation depth h measured in a direction perpendicular to the cross section in the thickness direction of the polyolefin layer under a load of 10 mN max Item 4. The adhesive film for a metal terminal according to any one of items 1 to 3, wherein the thickness is 3.0 μm or more. Item 5. The resin layer includes at least a substrate located on the polyolefin layer side and a polyester layer that constitutes the surface of the adhesive film for metal terminals on the exterior material side for the storage battery device, and at least one of the substrate and the polyester layer has a Martens hardness of 98 N / mm 2 or less measured in a direction perpendicular to a cross section in the thickness direction of the substrate and the polyester layer under the Martens hardness measurement conditions. 2 Item 5. An adhesive film for a metal terminal according to any one of items 1 to 4, which is: Item 6. An adhesive film for metal terminal according to Item 5, wherein the indentation modulus measured in a direction perpendicular to a cross section in the thickness direction of the substrate under the conditions for measuring the Martens hardness is 1500 MPa or less. Item 7. The adhesive film for metal terminal according to Item 5 or 6, wherein the thickness of the substrate is 60 μm or less. Item 8. The adhesive film for a metal terminal according to any one of Items 5 to 7, wherein the substrate includes a polyolefin skeleton. Item 9. The adhesive film for metal terminal according to any one of Items 5 to 8, wherein, under the conditions for measuring the Martens hardness, the indentation modulus measured in a direction perpendicular to a cross section in the thickness direction of the polyester layer is 2100 MPa or less. Item 10. The adhesive film for a metal terminal according to any one of Items 5 to 9, wherein the polyester layer has a thickness of 60 μm or less. Item 11. The adhesive film for a metal terminal according to any one of Items 1 to 10, wherein the adhesive film for a metal terminal has a thickness of 200 μm or less. 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 a metal terminal is composed of a laminate including, in this order, at least a polyolefin layer disposed on the metal terminal side and a resin layer disposed on the exterior material for an electricity storage device side; obtaining a laminate having the polyolefin layer and the resin layer in this order, The polyolefin layer has a Martens hardness of 37 N / mm when measured in a direction perpendicular to a cross section in the thickness direction of the polyolefin layer under the following measurement conditions: 2 is as follows: The resin layer has a Martens hardness of 98 N / mm when measured in a direction perpendicular to a cross section in the thickness direction of the resin layer under the following measurement conditions: 2 A method for producing an adhesive film for a metal terminal, comprising the following layers: <Measurement conditions for Martens hardness> The applied load is 10 mN. The load application rate is 1 mN / 10 seconds. The holding time is 10 seconds. The loading and unloading rate is 1 mN / 10 seconds. The indenter is a Vickers indenter with a square pyramid-shaped tip with an opposing angle of 136°. The measurement temperature is 25°C. The measurement values ​​were measured 10 times at different measurement locations, and the average value of a total of eight measurement values ​​was calculated, excluding one maximum value and one minimum value. 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 including at least the electricity storage device element including a positive electrode, a negative electrode, and an electrolyte, the electricity storage device casing material that seals the electricity storage device element, and the metal terminals that are electrically connected to the positive electrode and the negative electrode, respectively, and that protrude outside the electricity storage device casing material, 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 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 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. [Explanation of symbols]

[0161] 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 Polyolefin layer 12 Resin layer 12a Polyester layer 12b Base material 13 Adhesion promoter 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 a metal terminal is composed of a laminate including, in this order, at least a polyolefin layer disposed on the metal terminal side and a resin layer disposed on the exterior material for an electricity storage device side; The polyolefin layer has a Martens hardness of 37 N / mm when measured in a direction perpendicular to a cross section in the thickness direction of the polyolefin layer under the following measurement conditions: 2 is as follows: The resin layer includes at least a substrate located on the polyolefin layer side and a polyester layer constituting the surface of the adhesive film for metal terminals on the exterior material side for an electrical storage device, and at least one of the substrate and the polyester layer has a Martens hardness of 98 N / mm 2 or less when measured in a direction perpendicular to a cross section in the thickness direction of the substrate and the polyester layer under the Martens hardness measurement conditions described below; The adhesive film for a metal terminal, wherein the substrate comprises a polyolefin skeleton. <Measurement conditions for Martens hardness> The applied load is 10 mN. The load application rate is 1 mN / 10 seconds. The holding time is 10 seconds. The load unloading rate is 1 mN / 10 seconds. The indenter is a Vickers indenter having a square pyramid shape with a facing angle of 136° at the tip. The measurement temperature is 25°C. The measurement was performed 10 times at different measurement points, and the measurement value was the average value of a total of eight measurement values ​​excluding one maximum value and one minimum value.

2. 2. An adhesive film for metal terminals according to claim 1, wherein the indentation modulus measured in a direction perpendicular to a cross section in the thickness direction of the polyolefin layer under the conditions for measuring the Martens hardness is 700 MPa or less.

3. 3. The adhesive film for metal terminal according to claim 1, wherein the polyolefin layer has a thickness of 120 μm or less.

4. Under the conditions for measuring the Martens hardness, the indentation depth h measured in a direction perpendicular to the cross section in the thickness direction of the polyolefin layer under a load of 10 mN max The adhesive film for metal terminals according to any one of claims 1 to 3, wherein the thickness is 3.0 µm or more.

5. The adhesive film for metal terminals according to any one of claims 1 to 4, wherein the indentation modulus measured in a direction perpendicular to the cross section in the thickness direction of the substrate under the Martens hardness measurement conditions is 1500 MPa or less.

6. The adhesive film for metal terminals according to any one of claims 1 to 5, wherein the thickness of the substrate is 60 µm or less.

7. The adhesive film for metal terminals according to any one of claims 1 to 6, wherein the indentation modulus measured in a direction perpendicular to the thickness direction cross section of the polyester layer under the Martens hardness measurement conditions is 2100 MPa or less.

8. The adhesive film for metal terminals according to any one of claims 1 to 7, wherein the thickness of the polyester layer is 60 µm or less.

9. The adhesive film for metal terminal according to any one of claims 1 to 8, wherein the thickness of the adhesive film for metal terminal is 200 µm or less.

10. 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 a metal terminal is composed of a laminate including, in this order, at least a polyolefin layer disposed on the metal terminal side and a resin layer disposed on the exterior material for an electricity storage device side; obtaining a laminate having the polyolefin layer and the resin layer in this order, The polyolefin layer has a Martens hardness of 37 N / mm when measured in a direction perpendicular to a cross section in the thickness direction of the polyolefin layer under the following measurement conditions: 2 is as follows: The resin layer includes at least a substrate located on the polyolefin layer side and a polyester layer constituting the surface of the adhesive film for metal terminals on the exterior material side for an electrical storage device, and at least one of the substrate and the polyester layer has a Martens hardness of 98 N / mm 2 or less when measured in a direction perpendicular to a cross section in the thickness direction of the substrate and the polyester layer under the Martens hardness measurement conditions described below; A method for producing an adhesive film for a metal terminal, wherein the substrate comprises a polyolefin skeleton. <Measurement conditions for Martens hardness> The applied load is 10 mN. The load application rate is 1 mN / 10 seconds. The holding time is 10 seconds. The load unloading rate is 1 mN / 10 seconds. The indenter is a Vickers indenter having a square pyramid shape with a facing angle of 136° at the tip. The measurement temperature is 25°C. The measurement was performed 10 times at different measurement points, and the measurement value was the average value of a total of eight measurement values ​​excluding one maximum value and one minimum value.

11. A metal terminal with an adhesive film for a metal terminal, comprising the adhesive film for a metal terminal according to any one of claims 1 to 9 attached to a metal terminal.

12. 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 protrude outside the exterior material for an electricity storage device, An electricity storage device, comprising the adhesive film for metal terminals according to any one of claims 1 to 9 interposed between the metal terminals and the exterior material for electricity storage devices.

13. a manufacturing method for 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 protrude outside the exterior material for an electricity storage device, A method for manufacturing an electricity storage device, comprising a step of interposing the adhesive film for metal terminals according to any one of claims 1 to 9 between the metal terminals and the electricity storage device exterior material, and sealing the electricity storage device elements with the electricity storage device exterior material.

Images