Adhesive member for metal terminal and method for manufacturing same, metal terminal with adhesive member for metal terminal, power storage device using adhesive member for metal terminal, kit including adhesive member for metal terminal and exterior body for power storage device, and method for manufacturing power storage device

Abstract

Provided is an adhesive member for metal terminals having high electrical insulation with respect to metal terminals in high temperature environments.　This adhesive member for metal terminals is interposed between a metal terminal electrically connected to an electrode of a power storage device element and an exterior body for power storage devices that seals the power storage device element. The adhesive member for metal terminals includes at least a resin layer A constituting one surface of the adhesive member for metal terminals. When the resin layer A of the adhesive member for metal terminals is thermally fused to an aluminum alloy foil having a corrosion-resistant film on a surface thereof (200 μm in thickness × 15 mm in TD (width direction) × 100 mm in MD (length direction), using a flat plate press machine having a metal head on which silicone rubber is adhered, the silicone rubber having a thickness of 2.0 mm and a hardness of 30, under the conditions of a temperature of 260°C, a surface pressure applied to the silicone rubber of 1 MPa, and a duration of 13 seconds, an insulation reinforcement portion is formed on at least a part of the resin layer A. The corrosion-resistant film is formed by applying a chemical conversion treatment solution prepared at a mass ratio of 1:1:1 of a 7% aqueous solution of polyacrylic acid (weight average molecular weight: 250,000) and a 10% aqueous solution of polyethylene glycol (weight average molecular weight: 360-440), and a 28% aqueous ammonia solution, followed by drying for 10 minutes in an oven set at 150°C so as to have a film thickness in a range of 70-150 nm. The insulation reinforcement portion is a layer in which a peak top is not detected in a range from the softening point of the resin layer A or higher to a temperature 15°C higher than the softening point of the resin layer A or lower in nano-TA measurement performed using an atomic force microscope from the surface, at a portion that was a contact surface of t

Description

Adhesive member for metal terminals, method for manufacturing the same, metal terminal with the adhesive member for metal terminals, power storage device using the adhesive member for metal terminals, kit including the adhesive member for metal terminals and an exterior body for power storage device, and method for manufacturing a power storage device

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

[0002] Conventionally, various types of power storage devices have been developed. In every power storage device, an exterior material for power storage device is an essential member for sealing power storage device elements such as electrodes and electrolytes. Conventionally, a metal exterior material for power storage device has been frequently used as the exterior material for power storage device. However, in recent years, with the improvement of performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., various shapes have been required for power storage devices, and thinning and weight reduction have been demanded. However, the conventionally frequently used metal exterior material for power storage device has drawbacks that it is difficult to follow the diversification of shapes and there is also a limit to weight reduction.

[0003] Therefore, in recent years, a laminated sheet in which a base material layer / adhesive layer / barrier layer / heat-sealable resin layer are sequentially laminated has been proposed as an exterior material for power storage device that can be easily processed into various shapes and can achieve thinning and weight reduction. When using such a film-like exterior material for power storage device, the peripheral portion of the exterior material for power storage device is heat-sealed by heat sealing with the heat-sealable resin layers facing each other at the innermost layer of the exterior material for power storage device, whereby the power storage device elements are sealed by the exterior material for power storage device.

[0004] Metal terminals protrude from the heat-sealed portion of the casing material for energy storage devices. The energy storage device element sealed by the casing material is electrically connected to the outside by the metal terminals, which are electrically connected to the electrodes of the energy storage device element. In other words, in the heat-sealed portion of the casing material for energy storage devices, the portion where the metal terminals are present is heat-sealed with the metal terminals sandwiched between heat-fusible resin layers. Since the metal terminals and the heat-fusible resin layer are composed of dissimilar materials, adhesion tends to decrease at the interface between the metal terminals and the heat-fusible resin layer.

[0005] For this reason, an adhesive film is sometimes placed between the metal terminal and the heat-sealable resin layer to improve their adhesion. An example of such an adhesive film is the one described in Patent Document 1.

[0006] Japanese Patent Publication No. 2015-79638

[0007] The adhesive member placed between the metal terminal and the heat-sealable resin layer is heat-sealed at high temperature and pressure between the casing for the energy storage device and the metal terminal.

[0008] Furthermore, while lithium-ion batteries and other devices containing electrolytes are common as energy storage devices that use adhesive components, all-solid-state batteries, which use a solid electrolyte, are also known. Because all-solid-state batteries have a solid electrolyte, they can be charged quickly at high temperatures compared to energy storage devices that use electrolytes, and are intended for use in higher temperature environments compared to lithium-ion batteries and the like.

[0009] Solid-state batteries are sometimes manufactured by pressing the cells with metal terminals attached at high temperatures (e.g., around 150°C) to increase the ionic conductivity of the solid electrolyte, which can cause the metal terminals to reach high temperatures. Furthermore, during rapid charging and discharging, the temperature of the metal terminals can reach around 150°C due to resistive heating. Therefore, when applying the aforementioned adhesive material to solid-state batteries, high insulation properties against the metal terminals in high-temperature environments are required.

[0010] Under these circumstances, the primary objective of this disclosure is to provide an adhesive member for metal terminals that has high insulating properties for metal terminals in high-temperature environments. Furthermore, this disclosure also aims to provide a metal terminal with an adhesive member for metal terminals using the adhesive member for metal terminals, an energy storage device using the adhesive member for metal terminals, and a method for manufacturing the energy storage device.

[0011] The inventors of this disclosure have diligently studied to solve the above-mentioned problems. As a result, they have found that by using an adhesive member in which an insulating reinforcement layer (a layer in which no peak top is detected in the range of temperatures above the softening point of resin layer A and 15°C higher than the softening point of resin layer A, as an adhesive member for metal terminals, high insulating properties to metal terminals in high-temperature environments can be achieved. This disclosure was completed by further studies based on this finding.

[0012] That is, the present disclosure provides the invention in the following embodiments: an adhesive member for a metal terminal interposed between a metal terminal electrically connected to an electrode of an energy storage device element and an outer casing for an energy storage device that seals the energy storage device element, wherein the adhesive member for the metal terminal includes a resin layer A that constitutes at least one surface of the adhesive member for the metal terminal, and when the resin layer A of the adhesive member for the metal terminal is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a silicone rubber with a thickness of 2.0 mm and a hardness of 30, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, an insulating reinforcement portion is formed in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by dissolving a 7% aqueous solution of polyacrylic acid (weight-average molecular weight 250,000) and a 10% aqueous solution of polyethylene glycol (weight-average molecular weight 360 to 440) in a mass ratio of polyacrylic acid aqueous solution: polyethylene glycol aqueous solution: 28% ammonia water = 1:1:1, drying it in an oven set to 150°C for 10 minutes to a film thickness of 70 nm to 150 nm. The insulating reinforcement part is an adhesive member for metal terminals in which, after completely dissolving and removing the aluminum alloy foil with 10% hydrochloric acid, the area that was in contact with the aluminum alloy foil is washed with water, and nano-TA measurement is performed on the surface using an atomic force microscope, and no peak top is detected in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A.

[0013] This disclosure provides an adhesive member for metal terminals that has high insulation properties for metal terminals in high-temperature environments. Furthermore, this disclosure also aims to provide a method for manufacturing the adhesive member for metal terminals, a metal terminal with the adhesive member for metal terminals using the adhesive member for metal terminals, an energy storage device, a kit including the adhesive member for metal terminals and an outer casing for the energy storage device, and a method for manufacturing the energy storage device.

[0014] This is a schematic plan view of the energy storage device of the present disclosure. This is a schematic cross-sectional view along line A-A' in Figure 1. This is a schematic cross-sectional view along line B-B' in Figure 1. This is a schematic cross-sectional view of the adhesive member for metal terminals of the present disclosure. This is a schematic cross-sectional view of the adhesive member for metal terminals of the present disclosure. This is a schematic cross-sectional view of the adhesive member for metal terminals of the present disclosure. This is a schematic cross-sectional view of the adhesive member for metal terminals of the present disclosure. This is a schematic cross-sectional view of the casing for the energy storage device of the present disclosure. This is a schematic diagram of the energy storage device of the present disclosure. This is a schematic diagram of the energy storage device of the present disclosure. This is a schematic diagram of the energy storage device of the present disclosure. This is a schematic diagram of the energy storage device of the present disclosure. This is a schematic diagram of the energy storage device of the present disclosure.

[0015] The adhesive member for metal terminals of this disclosure is an adhesive member for metal terminals interposed between a metal terminal electrically connected to an electrode of an energy storage device element and an outer casing for an energy storage device that seals the energy storage device element, and includes a resin layer A that constitutes at least one surface of the adhesive member for metal terminals. When the resin layer A of the adhesive member for metal terminals is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a silicone rubber with a thickness of 2.0 mm and a hardness of 30, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, an insulating reinforcement portion is formed in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by mixing a 7% aqueous solution of polyacrylic acid (weight-average molecular weight 250,000, CAS No. 9003-01-4) and a 10% aqueous solution of polyethylene glycol (weight-average molecular weight 360 to 440) in a mass ratio of polyacrylic acid aqueous solution: polyethylene glycol aqueous solution: 28% ammonia water = 1:1:1, and drying it in an oven set to 150°C for 10 minutes to achieve a film thickness of 70 nm to 150 nm. The insulation reinforcement portion is formed by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing with water, and performing nano-TA measurement on the surface of the area that was in contact with the aluminum alloy foil using an atomic force microscope. The layer is one in which no peak top is detected in the range of temperatures above the softening point of resin layer A and 15°C higher than the softening point of resin layer A. The adhesive member for metal terminals of this disclosure, having such a configuration, exhibits high insulation properties for metal terminals in high-temperature environments.

[0016] Furthermore, the energy storage device of this disclosure comprises at least an energy storage device element having a positive electrode, a negative electrode, and an electrolyte; an outer casing for the energy storage device that seals the energy storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, for electrically connecting the outside of the energy storage device to the energy storage device element, wherein an adhesive member for metal terminals is interposed between the metal terminals and the outer casing for the energy storage device, the adhesive member for metal terminals includes a resin layer A that constitutes at least one side surface of the adhesive member for metal terminals, and an insulating reinforcement portion is formed on at least a part of the resin layer A of the adhesive member for metal terminals, the insulating reinforcement portion is a layer in which no peak top is detected in nano-TA measurement from the surface using an atomic force microscope in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A. By having such a configuration, the energy storage device of this disclosure exhibits high insulation between the outer casing for the energy storage device and the metal terminals in high-temperature environments.

[0017] The following describes in detail the adhesive member for metal terminals, the metal terminal with the adhesive member for metal terminals, the energy storage device using the adhesive member for metal terminals, and the method for manufacturing the energy storage device.

[0018] In this specification, numerical ranges indicated by "~" mean "greater than or equal to" and "less than or equal to" respectively. For example, the notation 2 to 15 mm means 2 mm or more and 15 mm or less. In numerical ranges described in stages in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Alternatively, upper and lower limits, upper and lower limits, or lower and lower limits described separately may be combined to form numerical ranges. Furthermore, in numerical ranges described in this disclosure, the upper or lower limit stated in one numerical range may be replaced with the values ​​shown in the examples.

[0019] Furthermore, XRD, Raman spectroscopy, and polarized IR can be used to confirm the MD of adhesive materials for metal terminals. Alternatively, for example, the thermal shrinkage rate of the adhesive material for metal terminals can be measured after leaving it in a 200°C environment for 2 minutes, and the material with the larger shrinkage rate can be determined to be MD.

[0020] [Adhesive Member for Metal Terminals 1] The adhesive member for metal terminals of this disclosure is interposed between a metal terminal electrically connected to the electrodes of an energy storage device element and an outer casing for an energy storage device that seals the energy storage device element. Specifically, as shown in Figures 1 to 3, for example, the adhesive member for metal terminals 1 of this disclosure is interposed between a metal terminal 2 electrically connected to the electrodes of an energy storage device element 4 and an outer casing material 3 for an energy storage device that seals the energy storage device element 4. The metal terminal 2 electrically connects the outside of the energy storage device to the energy storage device element, and in Figures 1 to 3, it protrudes to the outside of the outer casing material 3 for an energy storage device, and is sandwiched between the outer casing material 3 of the energy storage device via the adhesive member for metal terminals 1 at the peripheral edge 3a of the heat-sealed outer casing material 3 for an energy storage device.

[0021] As mentioned above, high temperatures of around 150°C are expected during processes such as the heating press process in the manufacturing of all-solid-state batteries and during rapid charging, and a service temperature of around 150°C is required. For this reason, the outer casing material 3 for energy storage devices must use a heat-sealable resin layer with a melting point of 150°C or higher. When heat-sealing the edges made up of the outer casing materials for energy storage devices, the heating temperature is usually in the range of 160 to 250°C, and the pressure is usually in the range of 0.5 to 2.0 MPa, and a flat metal sealing bar (heat sealing bar) is used for sealing. Similarly, for the edges where the metal terminals and the outer casing material for energy storage devices are heat-sealed via an adhesive member for metal terminals, the heating temperature is usually in the range of 160 to 250°C, and the pressure is usually in the range of 0.5 to 2.0 MPa, and a stepped metal sealing head is used, which has a step in the corresponding part of the sealing head to adjust for the difference due to the thickness of the metal terminals or the adhesive member for metal terminals, as needed. Furthermore, it is desirable to pre-bond the adhesive member to a predetermined position on the metal terminal. For example, when bonding by heat welding, it is common to perform multiple heating and pressurizing steps, such as a temporary bonding step and a final bonding step. The temporary bonding step is a step to temporarily fix the metal terminal and the adhesive member for metal terminals and remove air bubbles, while the final bonding step is a step to bond the adhesive member for metal terminals to the metal terminals by performing one or more heating and pressurizing steps at a higher temperature than the temporary bonding step. The preliminary bonding process for the adhesive material for metal terminals to the metal terminals is performed using a metal seal head covered with heat-resistant rubber with a hardness of approximately 20 to 50 and a thickness of approximately 2 to 5 mm, at a temperature of approximately 160 to 230°C, a pressure of approximately 0.1 to 0.5 MPa, for a time of approximately 10 to 20 seconds, and with 1 to 2 sealing cycles. The main bonding process aims to thermally fuse the adhesive material for metal terminals to the metal terminals, and is performed using a metal seal head covered with heat-resistant rubber with a hardness of approximately 20 to 50 and a thickness of approximately 2 to 5 mm, at a temperature of approximately 180 to 250°C, a pressure of approximately 0.2 to 1.0 MPa, for a time of approximately 10 to 30 seconds, and with 1 to 2 sealing cycles. Furthermore, if necessary, efficient welding can be achieved by providing a step in the relevant part of the seal head to adjust for the difference in thickness due to the metal terminal or the adhesive material for metal terminals.Furthermore, if the energy storage device to which the adhesive member for metal terminals of this disclosure is applied is an all-solid-state battery, then particularly high temperatures and pressures will be applied to the adhesive member for metal terminals. The method of attaching the adhesive member for metal terminals exemplified herein is merely an example and is not limited to any specific method; for example, the pressurization time may be appropriately adjusted depending on the thickness of the adhesive member for metal terminals.

[0022] The adhesive member 1 for metal terminals of this disclosure is provided, for example, to improve the adhesion between the metal terminal 2 and the exterior material 3 for the energy storage device. By improving the adhesion between the metal terminal 2 and the exterior material 3 for the energy storage device, the sealing performance of the energy storage device element 4 is improved. As described above, when heat sealing the energy storage device element 4, the metal terminal 2 electrically connected to the electrodes of the energy storage device element 4 protrudes to the outside of the exterior material 3 for the energy storage device, thereby sealing the energy storage device element. At this time, both the adhesive member 1 for metal terminals and the heat-sealable resin layer 35 located in the innermost layer of the exterior material 3 for the energy storage device are required to withstand temperatures of about 130°C. However, if these are formed from dissimilar materials, the sealing performance of the energy storage device element tends to be low at the interface with the heat-sealable resin layer 35.

[0023] Furthermore, as shown in Figures 9 to 13, in this disclosure, the energy storage device elements of the energy storage device 10 may be sealed by other members such as a lid 36 and a frame 37 in addition to the energy storage device exterior material 3. That is, the energy storage device exterior material 3, the lid 36, the frame 37 and other members constitute an exterior (an exterior for the energy storage device) that seals the energy storage device elements. As shown in Figures 9, 10 and 12, for example, the energy storage device elements may be housed inside the cylindrical energy storage device exterior material 3, and the opening may be closed by the lid 36. Also, as shown in Figures 11 and 13, for example, the energy storage device elements may be housed inside the cylindrical energy storage device exterior material 3, and the opening may be closed by the lid 36 and the frame 37. In Figures 11 and 13, the frame 37 is a cylindrical member disposed between the energy storage device exterior material 3 and the lid 36. In another example, the energy storage device element, connected to a lid, may be housed inside the cylindrical outer casing material 3 for the energy storage device, with an opening formed therein, and the opening may be closed by the lid. The lid and the outer casing material for the energy storage device are preferably joined by any means. From the viewpoint of reducing dead space between the energy storage device element and the outer casing material for the energy storage device in order to improve the volumetric energy density of the energy storage device, it is preferable that the outer casing material for the energy storage device is wrapped around the energy storage device element and the lid.

[0024] The cover can be formed, for example, from a resin molded product, a metal molded product, an exterior material for an energy storage device, or a combination thereof. In this disclosure, when the cover is described as a resin molded product, the cover is not composed solely of a film as defined by JIS K6900-1994 [Plastics - Terminology]. When the cover is a metal molded product, the cover can also function as a metal terminal, and therefore the cover can be a metal terminal. The cover may be composed of a resin material and a conductive material.

[0025] For example, in the schematic diagram shown in Figure 9, an energy storage device element is housed inside a cylindrical outer casing material 3 for the energy storage device, and the opening is closed by a resin lid 36. The lid 36 also has a through hole into which a metal terminal 2 electrically connected to the energy storage device element 4 is inserted. In this embodiment, the energy storage device 10 consists of an outer casing material 3 and a lid 36 that seals the energy storage device element 4, and the metal terminal 2 is exposed to the outside through the through hole in the lid 36. The adhesive member 1 for the metal terminal of this disclosure is interposed between the metal terminal 2 electrically connected to the electrodes of the energy storage device element and the lid 36 of the outer casing. The adhesive member 1 for the metal terminal of this disclosure covers the periphery of the metal terminal 2 between the lid 36 and the metal terminal 2.

[0026] On the other hand, for example, in the schematic diagram shown in Figure 10, an energy storage device element is housed inside a cylindrical exterior material 3 for the energy storage device, and the opening is closed by a cover 36 which serves as a metal terminal. In this embodiment, the exterior material 3 for the energy storage device constitutes the exterior body for the energy storage device, and the metal cover 36 constitutes a metal terminal. The adhesive member 1 for the metal terminal of this disclosure is interposed between the metal terminal (cover) electrically connected to the energy storage device element and the electrode, and the exterior body (exterior material 3) for the energy storage device that seals the energy storage device element. The adhesive member 1 for the metal terminal of this disclosure covers the periphery of the cover 36 between the exterior body and the cover 36.

[0027] Furthermore, for example, in the schematic diagram shown in Figure 11, an energy storage device element is housed inside a cylindrical exterior material 3 for the energy storage device, and the opening is closed by a lid 36 which serves as a metal terminal and a resin frame 37. In this embodiment, the exterior material 3 and the frame 37 constitute the exterior body for the energy storage device, and the metal lid 36 constitutes a metal terminal. The adhesive member 1 for the metal terminal of this disclosure is interposed between the metal terminal (lid) electrically connected to the energy storage device element and the electrode, and the frame 37 of the exterior body for the energy storage device that seals the energy storage device element. The adhesive member 1 for the metal terminal of this disclosure covers the periphery of the lid 36 between the frame 37 and the lid 36.

[0028] Furthermore, in the schematic diagram shown in Figure 12, for example, an energy storage device element is housed inside a cylindrical outer casing material 3 for the energy storage device, and the opening is closed by a resin lid 36. The lid 36 is provided with a through hole into which a metal terminal 2 electrically connected to the energy storage device element 4 is inserted. In this embodiment, the energy storage device 10 has an outer casing material 3 for the energy storage device that seals the energy storage device element 4, and the metal terminal 2 is exposed to the outside through the through hole in the lid 36. The lid 36 constitutes the adhesive member 1 for the metal terminal of this disclosure and is interposed between the metal terminal 2 electrically connected to the electrodes of the energy storage device element and the outer casing material 3 for the energy storage device.

[0029] Furthermore, for example, in the schematic diagram shown in Figure 13, an energy storage device element is housed inside a cylindrical exterior material 3 for the energy storage device, and the opening is closed by a lid 36 which serves as a metal terminal and a resin frame 37. In this embodiment, the exterior material 3 for the energy storage device constitutes the exterior body for the energy storage device, and the metal lid 36 constitutes a metal terminal. The frame 37 constitutes the adhesive member 1 for metal terminals of this disclosure and is interposed between the metal terminal (lid) electrically connected to the energy storage device element and the electrode, and the exterior material 3 for the energy storage device that seals the energy storage device element. The adhesive member 1 for metal terminals (frame 37) of this disclosure covers the periphery of the lid 36.

[0030] As described above, even in the embodiment shown in Figures 9 to 13, in which the energy storage device 10 comprises an exterior material 3 for the energy storage device and a cover 36, the adhesive member 1 for metal terminals of this disclosure is interposed between the metal terminals electrically connected to the electrodes of the energy storage device element and the exterior material for the energy storage device that seals the energy storage device element.

[0031] At least one surface of the adhesive member 1 for metal terminals of this disclosure is formed of a resin layer A. That is, the adhesive member 1 for metal terminals of this disclosure includes at least one resin layer A, and at least one surface of the adhesive member 1 for metal terminals is formed of a resin layer A. To the extent that the effects of this disclosure are achieved, the adhesive member 1 for metal terminals of this disclosure may be a single layer as shown in Figure 4, or a multi-layered layer as shown in Figures 5 to 7.

[0032] When the adhesive member 1 for metal terminals of this disclosure is a single layer, the adhesive member 1 for metal terminals is composed of a resin layer A, and the surface on the metal terminal side and the surface of the exterior material for the energy storage device are formed by the resin layer A. In this case, the resin forming the surface of the adhesive member 1 for metal terminals on the exterior material side for the energy storage device and the resin forming the surface on the metal terminal side are a common resin (i.e., the resin constituting the resin layer A). Note that "common" means that, for example, 80% or more by mass of the resin forming the surface on the exterior material side for the energy storage device and the resin forming the surface on the metal terminal side of these resins are the same, 90% or more by mass are the same, 95% or more by mass are the same, or 100% by mass are the same, etc.

[0033] When the adhesive member 1 for metal terminals of this disclosure is multilayered, it is sufficient that at least one layer is made of resin layer A. For example, as shown in Figure 5, when the adhesive member 1 for metal terminals of this disclosure has a two-layer structure, the adhesive member 1 for metal terminals is a laminate of a first resin layer 12a and a second resin layer 12b, and at least one of these layers is made of resin layer A. Even when the adhesive member 1 for metal terminals of this disclosure is multilayered, it is preferable that the resin forming the surface on the exterior material side for the energy storage device and the resin forming the surface on the metal terminal side are the same resin.

[0034] For example, as shown in Figure 6, when the adhesive member 1 for metal terminals of this disclosure has a three-layer structure, the adhesive member 1 for metal terminals is a laminate in which a first resin layer 12a, an intermediate layer 11, and a second resin layer 12b are laminated in this order, and at least one of these layers, the first resin layer 12a and the second resin layer 12b, is made of resin layer A. The intermediate layer 11 preferably has excellent heat resistance, and when insulation is preferentially required, the melting point of the intermediate layer 11 is preferably 250°C or higher, and more preferably 250 to 330°C.

[0035] The adhesive member 1 for metal terminals of this disclosure may be composed of four or more layers. For example, as shown in Figure 7, an adhesion promoter layer 13 may be laminated between the first resin layer 12a and the intermediate layer 11, and between the second resin layer 12b and the intermediate layer 11.

[0036] In this disclosure, the first resin layer 12a is arranged on the metal terminal side, and the second resin layer 12b is arranged on the exterior material 3 side for the energy storage device. The surface of the adhesive member 1 for metal terminals in this disclosure on the metal terminal side has heat-sealing properties to metal (the metal constituting the metal terminal), and the surface on the exterior material side for the energy storage device has heat-sealing properties to the heat-sealable resin layer described later. It is preferable that the surface on the metal terminal side is composed of resin layer A. Furthermore, it is also preferable that the surface on the exterior material side for the energy storage device is composed of resin layer A.

[0037] The resin layer A included in at least one layer of the adhesive member 1 for metal terminals of this disclosure has, for example, a melting point of about 150 to 270°C. The melting point of the resin layer A is the endothermic peak measured by a differential scanning calorimetry (DSC).

[0038] In this disclosure, the resin forming the resin layer A is a layer in which an insulating reinforcement portion is formed in at least a part of the resin layer A when heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a 2.0 mm thick, hardness 30 silicone rubber, at a temperature of 260°C, a surface pressure of 1 MPa applied to the silicone rubber, and for 13 seconds. Here, the corrosion-resistant coating is formed by applying a chemical conversion treatment solution made by preparing a 7% aqueous solution of polyacrylic acid (weight average molecular weight 250,000) and a 10% aqueous solution of polyethylene glycol (weight average molecular weight in the range of 360 to 440) in a mass ratio of polyacrylic acid aqueous solution: polyethylene glycol aqueous solution: 28% ammonia water = 1:1:1, and drying it in an oven set to 150°C for 10 minutes to a film thickness in the range of 70 nm to 150 nm. The aforementioned insulation-reinforced portion is a layer in which, after completely dissolving and removing the aluminum alloy foil with 10% hydrochloric acid, the area that was in contact with the aluminum alloy foil is washed with water, and nano-TA measurement is performed on the surface using an atomic force microscope. No peak top is detected in the range of temperature above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A. The resin layer A is not particularly limited, as long as such an insulation-reinforced portion is formed in at least a part of it, but from the viewpoint of suitably exhibiting the effects of the present invention, it is preferable that it contains polyester, and more preferably that it is formed of polyester.

[0039] From the viewpoint of suitably exhibiting the effects of the present invention, the resin forming the resin layer A preferably contains at least one of the following polyesters: homopolybutylene terephthalate (hereinafter sometimes referred to as homoPBT), copolymerized polybutylene terephthalate (hereinafter sometimes referred to as copolymerized PBT), polyethylene terephthalate (hereinafter sometimes referred to as PET), and copolymerized polyethylene terephthalate (hereinafter sometimes referred to as copolymerized PET). More preferably, the resin layer A is formed of at least one of homoPBT, copolymerized PBT, PET, and copolymerized PET.

[0040] Further, from the viewpoint of preferably exerting the effects of the invention of the present disclosure, the resin layer A is preferably a resin layer made of a homopolybutylene terephthalate film (hereinafter sometimes referred to as a homopolymer PBT layer), or a resin layer made of a copolymerized polybutylene terephthalate film (hereinafter sometimes referred to as a copolymerized PBT layer).

[0041] The homopolymer PBT layer is a resin layer made of a homopolybutylene terephthalate film, and the resin contained in the homopolymer PBT layer is substantially (for example, 99% by mass or more, further 100% by mass or more) only homopolybutylene terephthalate. That is, the homopolymer PBT layer is formed of a homopolybutylene terephthalate film that substantially does not contain a resin different from homopolybutylene terephthalate. For example, the homopolymer PBT layer is a layer made of a homopolybutylene terephthalate film that does not contain copolymerized polybutylene terephthalate.

[0042] Further, the homopolybutylene terephthalate may be acid-modified or may not be acid-modified. When the homopolybutylene terephthalate is acid-modified homopolybutylene terephthalate, the acid modification of the homopolybutylene terephthalate can be performed with an acid component such as maleic anhydride or acrylic acid.

[0043] Further, the copolymerized PBT contains other copolymerized units in addition to the polybutylene terephthalate structure. The copolymerized PET contains other copolymerized units in addition to the polyethylene terephthalate structure. It is more preferable that the other copolymerized units contain at least one selected from the group consisting of a polyether structure and a polyester structure B.

[0044] The polybutylene terephthalate structure is a structure formed by polymerizing terephthalic acid and 1,4-butanediol, and contains two types of structural units, a structure derived from terephthalic acid and a structure derived from 1,4-butanediol.

[0045] On the other hand, a polyether structure can be formed by introducing a compound (monomer) having a polyether structure into a resin. Examples of methods for introducing a polyether structure into a resin include a method of using a compound having a polyether structure as a polyvalent carboxylic acid and a method of using a compound having a polyether structure as a polyol that reacts with a polyvalent carboxylic acid. The polyether structure preferably constitutes the soft segment of the resin in the film. Compounds (monomers) that undergo polycondensation reaction with a polyvalent carboxylic acid having a polybutylene terephthalate structure to form such a soft segment include diols capable of exhibiting elasticity, such as polytetramethylene ether glycol and neopentyl glycol. The polyether structure is preferably a polyether structure derived from at least one selected from the group consisting of polytetramethylene ether glycol and neopentyl glycol. Polytetramethylene ether glycol, neopentyl glycol, etc. form structural units in the polyether structure of the resin. By introducing a polyether structure into the resin as a soft segment, the rubber elasticity of the resin is enhanced and the resin is less likely to break, so that high sealing strength is preferably exhibited in a wide temperature environment from low temperature to high temperature.

[0046] Furthermore, polyester structure B is a polyester structure different from the polybutylene terephthalate structure. Polyester structure B can be introduced into copolymerized PBT by using compounds (monomers) that form a polyester structure through polycondensation reactions with polyols such as ethylene glycol, butanediol, pentanediol, hexanediol, neopentyl glycol, diethylene glycol, polytetramethylene glycol, cyclohexanedimethanol, and propanediol. It is desirable that polyester structure B constitutes the soft segment of the resin in the film. Examples of compounds (monomers) that form such a soft segment through polycondensation reactions with polyols of the polybutylene terephthalate structure include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, dodecanedionic acid, and cyclohexanedicarboxylic acid (aliphatic dicarboxylic acids with 4 to 20 carbon atoms are preferred). Aromatic dicarboxylic acids and aliphatic dicarboxylic acids form polyester structure B. Polyester structure B is particularly preferably a polyester structure formed by polycondensation of a polyol with at least one dicarboxylic acid selected from the group consisting of isophthalic acid, sebacic acid, and dodecanedionic acid. By introducing polyester structure B as a soft segment into the resin, the rubber elasticity of the resin is increased, making the resin less prone to breakage, and thus high seal strength is suitably exhibited in a wide temperature range from low to high temperatures.

[0047] From the viewpoint of more favorably exhibiting the effects of the present invention, the resin forming the surface of at least one side of the adhesive member 1 for metal terminals further includes a polyether structure in addition to the polybutylene terephthalate structure, and it is particularly preferable that the polyether structure has a polycondensation structure of at least one of polytetramethylene ether glycol and neopentyl glycol and terephthalic acid of the polybutylene terephthalate structure. Furthermore, it is particularly preferable that the resin further includes a polyester structure B in addition to the polybutylene terephthalate structure, and that the polyester structure B has a polycondensation structure of at least one selected from the group consisting of isophthalic acid, dodecanedionic acid, and sebacic acid and 1,4-butanediol of the polybutylene terephthalate structure.

[0048] Furthermore, from the viewpoint of more favorably exhibiting the effects of the present invention, it is preferable that the resin layer A forming at least one surface of the adhesive member 1 for metal terminals has a polybutylene terephthalate structure as its main component. The term "main component" means that the proportion of the polybutylene terephthalate structure relative to 100 mol% of the total components constituting the resin layer A is 50 mol% or more, preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 mol% or more. Also, the proportion of at least one of the polyether structure and the dicarboxylic acid structure in the resin layer A is preferably about 2 to 30 mol%, more preferably about 3 to 25 mol%, and even more preferably about 3 to 20 mol%, relative to 100 mol% of the total components (total monomer units) constituting the resin layer A.

[0049] From the viewpoint of suitably exhibiting the effects of this disclosure, the thickness of resin layer A is preferably about 20 μm or more, more preferably about 30 μm or more, and even more preferably about 50 μm or more. Also, from the same viewpoint, the thickness is preferably about 300 μm or less, more preferably about 200 μm or less, and preferably about 100 μm or less. Furthermore, the preferred range of the thickness is about 20 to 300 μm, about 20 to 200 μm, about 20 to 100 μm, about 30 to 300 μm, about 30 to 200 μm, about 30 to 100 μm, about 50 to 300 μm, about 50 to 200 μm, and about 50 to 100 μm.

[0050] The adhesive member 1 for metal terminals of this disclosure may include at least one other resin layer different from resin layer A. However, from the viewpoint of ensuring high insulation of the adhesive member 1 for metal terminals of this disclosure to metal terminals in a high-temperature environment, it is preferable that the other resin layer has a melting point of 150°C or higher. The melting point of the other resin layer is preferably about 150 to 330°C, more preferably about 180 to 280°C. The melting point of the other resin layer is the endothermic peak measured by a differential scanning calorimeter (DSC).

[0051] Furthermore, if two or more other resin layers are included, the composition of each of the other resin layers may be the same or different. Similarly, if two or more resin layers A are included, the composition of each of the resin layers A may be the same or different.

[0052] From the viewpoint of suitably exhibiting the effects of this disclosure, the thickness of the other resin layer is preferably about 20 μm or more, more preferably about 50 μm or more, and even more preferably about 80 μm or more. Also, from the same viewpoint, the thickness is preferably about 300 μm or less, more preferably about 200 μm or less, and even more preferably about 100 μm or less. Furthermore, the preferred range for the thickness is about 20 to 300 μm, about 20 to 200 μm, about 20 to 100 μm, about 50 to 300 μm, about 50 to 200 μm, about 50 to 100 μm, about 80 to 300 μm, about 80 to 200 μm, and about 80 to 100 μm.

[0053] When the adhesive member 1 for metal terminals of this disclosure includes other resin layers, examples of the laminated structure of the adhesive member 1 for metal terminals include: a laminate in which the first resin layer 12a in Figure 5 is resin layer A and the second resin layer 12b is another resin layer; a laminate in which the first resin layer 12a in Figure 6 or Figure 7 is resin layer A and the intermediate layer 11 and the second resin layer 12b are other resin layers; a laminate in which the first resin layer 12a and the second resin layer 12b in Figure 6 or Figure 7 are resin layer A and the intermediate layer 11 is another resin layer; and a laminate in which the first resin layer 12a and the intermediate layer 11 in Figure 6 or Figure 7 are resin layer A and the second resin layer 12b is another resin layer.

[0054] The resins constituting the other resin layers are not particularly limited, as long as they do not hinder the purpose of the adhesive member 1 for metal terminals of this disclosure. Examples include polyolefin resins, polyamide resins, polyester resins, epoxy resins, acrylic resins, fluororesins, silicon resins, phenolic resins, polyetherimide, polyimide, polycarbonate, and mixtures or copolymers thereof. Particularly preferred are polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, polyetheretherketone, and polyimide, due to their excellent heat resistance. When the adhesive member 1 for metal terminals of this disclosure is multilayered, specific examples of the laminated structure include a laminated structure in which resin layer A / fluororesin layer / resin layer A is laminated in this order, and a laminated structure in which resin layer A / polyethylene naphthalate layer / resin layer A is laminated in this order. More specifically, examples include a laminated configuration in which homo-PBT / copolymerized PBT is laminated in this order, a laminated configuration in which modified polybutylene terephthalate (hereinafter, modified PBT) / homo-PBT is laminated in this order, a laminated configuration in which modified PBT / copolymerized PBT is laminated in this order, and a laminated configuration in which modified PBT / homo-PBT / copolymerized PBT is laminated in this order. In these laminated configurations, the layer constituting the surface of at least one side of the adhesive member for metal terminals is the resin layer A. Furthermore, modified PBT such as acid-modified polybutylene terephthalate (acid-modified PBT) modified with an acid component such as maleic anhydride or acrylic acid as described above has excellent adhesion to metal terminals, so it is preferable to use the adhesive member for metal terminals 1 of this disclosure such that the modified PBT as the resin layer A is on the metal terminal side.

[0055] Resin layer A and the other resin layers may each further contain additives such as fillers as needed. By including fillers, the fillers function as spacers, making it possible to effectively suppress short circuits between the metal terminals 2 and the barrier layer 33 of the outer material 3 for the energy storage device. The particle size of the fillers can be in the range of about 0.1 to 35 μm, preferably about 5.0 to 30 μm, and more preferably about 10 to 25 μm. The filler content can be about 5 to 30 parts by mass, more preferably about 10 to 20 parts by mass, per 100 parts by mass of the resin components forming resin layer A and the other resin layers.

[0056] Both inorganic and organic fillers can be used. 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, polymethyl methacrylate crosslinked products, and polyethylene crosslinked products. From the viewpoint of shape stability, rigidity, and content resistance, aluminum oxide, silica, fluororesins, acrylic resins, and benzoguanamine-formaldehyde condensates are preferred, and among these, spherical aluminum oxide and silica are particularly preferred. As for the method of mixing the filler with resin layer A and the resin components forming other resin layers, methods such as melt-blending the two in advance using a Banbury mixer or the like to create a masterbatch and then mixing it in a predetermined ratio can be employed, or a direct mixing method with the resin components can be used.

[0057] Furthermore, resin layer A and the other resin layers may each contain pigments as needed. Various inorganic pigments can be used as pigments. Specific examples of pigments include carbon (carbon, graphite) as exemplified in the filler above. Carbon (carbon, graphite) is a material commonly used inside energy storage devices and does not leach into the electrolyte. In addition, a sufficient coloring effect can be obtained with an amount that does not significantly impede adhesion, and it does not melt with heat, thus increasing the apparent melt viscosity of the added resin. Furthermore, it prevents the pressurized area from becoming thin during heat bonding (heat sealing), providing excellent sealing between the energy storage device exterior material and the metal terminals.

[0058] When adding pigment to resin layer A and other resin layers, the amount added is, for example, when using carbon black with a particle size of about 0.03 μm, about 0.05 to 0.3 parts by mass, preferably about 0.1 to 0.2 parts by mass, per 100 parts by mass of the resin components forming resin layer A and other resin layers. By adding pigment to resin layer A or other resin layers, the presence or absence of the adhesive member 1 for metal terminals can be detected by a sensor or inspected visually.

[0059] The resin layer A may contain an elastomer, but it is preferable that it does not contain an elastomer.

[0060] In this disclosure, when a resin layer A of an adhesive member for metal terminals is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press machine with a metal head attached to a 2.0 mm thick, hardness 30 silicone rubber, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, an insulating reinforcement portion is formed on at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical conversion treatment solution made by preparing a 7% aqueous solution of polyacrylic acid (weight average molecular weight 250,000) and a 10% aqueous solution of polyethylene glycol (weight average molecular weight 360 to 440) in a mass ratio of polyacrylic acid aqueous solution: polyethylene glycol aqueous solution: 28% ammonia water = 1:1:1, and drying it in an oven set to 150°C for 10 minutes to a film thickness in the range of 70 nm to 150 nm. The aforementioned insulation reinforcement portion is a layer in which, after completely dissolving and removing the aluminum alloy foil with 10% hydrochloric acid, the area that was in contact with the aluminum alloy foil is washed with water, and nano-TA measurement is performed on the surface using an atomic force microscope. No peak top is detected in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A.

[0061] Furthermore, "softening point of resin layer A" refers to the softening point of the portion of resin layer A where the insulation reinforcement portion has not been formed.

[0062] Regarding the insulation reinforcement section, "no peak top is detected in the range of temperatures above the softening point of resin layer A and 15°C higher than the softening point of resin layer A" means that the insulation reinforcement section does not have a softening point in the range from the softening point of resin layer A to 15°C higher than that softening point (i.e., the softening point range is 15°C).

[0063] From the viewpoint of more favorably demonstrating the effects of the invention disclosed herein, it is preferable that the insulation reinforcement portion is a layer in which no peak top is detected in the range above the softening point of the resin layer A and below a temperature of 250°C when nano-TA measurement is performed from the surface using an atomic force microscope.

[0064] The insulation reinforcement portion is a layer formed on at least a part of the resin layer A by heat-fusion bonding it to an aluminum alloy foil having a corrosion-resistant coating formed on its surface by the aforementioned chemical conversion treatment liquid. The insulation reinforcement portion is formed, for example, in the portion of the resin layer A that comes into contact with a metal terminal.

[0065] Furthermore, if, for example, the thickness of resin layer A is thin and its presence is difficult to confirm from the cross-section of the adhesive member for metal terminals, then resin layer A should be confirmed from a direction perpendicular to the thickness direction of the adhesive member for metal terminals. For example, if the adhesive member for metal terminals is composed of a single layer, the presence of resin layer A can be confirmed from the surface of the adhesive member for metal terminals.

[0066] From the viewpoint of suitably exhibiting the effects of this disclosure, the thickness of the insulation reinforcement portion is preferably about 1 μm or more, more preferably about 2 μm or more, and even more preferably about 5 μm or more. Also, from the same viewpoint, the thickness is preferably about 10 μm or less, more preferably about 5 μm or less. Furthermore, the preferred range of the thickness is about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, about 2 to 5 μm, and about 5 to 10 μm.

[0067] The softening point of the adhesive material for metal terminals can be measured using the following procedure [Preparation of metal terminals with adhesive material for metal terminals] and [Measurement of the softening point of the adhesive material for metal terminals], and the specific measurement method is as described in the examples.

[0068] [Preparation of Metal Terminals with Adhesive Members for Metal Terminals] Prepare aluminum alloy foil (thickness 200 μm x TD (width direction) 15 mm x MD (length direction) 100 mm) or nickel-plated copper foil (thickness 200 μm x TD (width direction) 15 mm x MD (length direction) 100 mm) as metal terminals. Apply a chemical treatment solution to the surface of the metal terminals, which does not contain metals such as chromium, by mass ratio of polyacrylic acid aqueous solution:polyethylene glycol aqueous solution:28% ammonia water = 1:1:1, which is made by mass ratio of polyacrylic acid aqueous solution:polyethylene glycol aqueous solution:28% ammonia water, and drying in an oven set to 150°C for 10 minutes to form a corrosion-resistant film (thickness in the range of 70 to 150 nm) with a film thickness in the range of 70 nm to 150 nm, thereby creating surface-treated metal terminals. Furthermore, since polyacrylic acid (weight-average molecular weight 250,000) is a high-molecular-weight compound, even if commercially available polyacrylic acid is labeled as having a weight-average molecular weight of 250,000, the actual measured weight-average molecular weight can range from, for example, 220,000 to 280,000, and such commercially available polyacrylic acid can be used in this disclosure. Next, two pieces of adhesive material for metal terminals, which had been stored in a dry room (23°C, dew point temperature -40°C) for more than 24 hours, were cut to a size of TD (width direction) 10 mm × MD (length direction) 55 mm. Using a metal head flat plate press machine, the MDs of these two adhesive members for metal terminals and the MD of the surface-treated metal terminal are aligned perpendicularly, and 2.0 mm thick, hardness 30 silicone rubber is attached to both the top and bottom (i.e., the top and bottom (front and back) of the surface-treated metal terminal) at a position 10 mm from the edge of the MD (length direction) of the surface-treated metal terminal (i.e., 10 mm from the edge). The press machine is then heat-sealed at a temperature of 260°C, a pressure of 1 MPa (surface pressure on the silicone rubber), and for 13 seconds, to prepare a metal terminal with adhesive members for metal terminals, in which adhesive members for metal terminals / metal terminals / adhesive members for metal terminals are laminated in that order.

[0069] [Measurement of the softening point of the adhesive member for metal terminals] A sample is obtained by cutting the portion of the metal terminal with the adhesive member for metal terminals, prepared in the above-mentioned [Preparation of metal terminals with adhesive member for metal terminals], where the adhesive member is heat-fused to the metal terminal, in the thickness direction. The size of the sample should be such that the length in the vertical and horizontal directions (XY directions), which are perpendicular to the thickness direction (Z direction), is 1 mm or more. The sample should include the metal terminal. In the thickness direction (Z direction), the entire laminate of adhesive member / metal terminal / adhesive member may be cut in the thickness direction, or only the adhesive member / metal terminal portion may be cut. If the metal terminal has a thickness of 1 mm or more, it is desirable to reduce the thickness of the metal terminal portion to less than 1 mm (preferably about 200 μm) before preparing the sample. Next, if the metal terminal is aluminum alloy foil, the sample is immersed in a sufficient amount of 10% hydrochloric acid to completely dissolve and remove the metal terminal. If the metal terminal is nickel-plated copper foil, the sample is immersed in a sufficient amount of concentrated nitric acid to completely dissolve and remove the metal terminal. The adhesive material for metal terminals obtained by dissolving and removing all metal terminals is washed with water three times, wiped dry, and air-dried for 24 hours. Then, the softening point of the adhesive material for metal terminals is measured under the following test conditions. The insulation reinforcement portion of the adhesive material for metal terminals and the resin layer A where the insulation reinforcement portion is not formed are both measured. The insulation reinforcement portion is measured from the surface at the location that was in contact with the metal terminal. The measurement location for the resin layer A where the insulation reinforcement portion is not formed differs depending on whether the adhesive material for metal terminals is single-layer or multi-layer. If the adhesive material for metal terminals is single-layer, the measurement location is the part opposite to the contact surface with the metal terminal and not in contact with the metal terminal, and the measurement is taken from its surface. If the adhesive material for metal terminals is multi-layer, a cross-section is prepared, and the resin layer A on the metal terminal side where the insulation reinforcement layer is not formed is used as the measurement location and the measurement is taken from the cross-sectional direction.

[0070] (Test Conditions) The softening point is determined by nano-TA measurement using an atomic force microscope (AFM) equipped with a nanothermal microscope consisting of a cantilever with a heating mechanism. The following calibration is performed before measurement. Polycaprolactone (softening temperature: 55°C), polyethylene (softening temperature: 116°C), and polyethylene terephthalate (softening temperature: 235°C), whose softening temperatures are known, are used as standard samples. Each standard sample is heated while in contact with a thermal probe. During heating, the thermal expansion directly beneath the thermal probe is measured, and a graph representing Deflection (displacement) against Voltage (potential) is obtained. The measurement conditions set on the instrument are as follows: The starting voltage is 0.1V, the ending voltage is 10V, the speed is 0.2V / sec, and the Deflection setting is -4V. Using the softening temperature of each standard sample, the graph representing the displacement of the thermal probe against potential is converted into a graph representing the displacement against temperature. Calibration (n=3) is performed in this manner. Heating rate: 10°C / sec Heating start temperature: 40°C Atomic force microscope (AFM) measurement area: 10 μm The softening point is calculated from the peak top. The average value obtained from three measurements with different measurement locations is adopted.

[0071] The softening point of the resin layer A, as measured by the above method, is preferably about 150°C or higher, more preferably about 170°C or higher, even more preferably about 180°C or higher, and also preferably about 280°C or lower, more preferably about 260°C or lower, and even more preferably about 250°C or lower. Preferred ranges include approximately 150 to 280°C, 150 to 260°C, 150 to 250°C, 170 to 280°C, 170 to 260°C, 170 to 250°C, 180 to 280°C, 180 to 260°C, and 180 to 250°C.

[0072] Furthermore, while aluminum alloy and nickel-plated copper are preferred materials for the metal terminals used to confirm the formation of the insulation reinforcement portion in the resin layer A, the material of the metal terminals used when applying the adhesive member for metal terminals of this disclosure to an energy storage device may be appropriately selected according to the type of energy storage device, etc., and is not limited to aluminum alloy and nickel-plated copper.

[0073] In order to suitably form an insulating reinforcement portion in resin layer A, it is preferable that a chemical conversion treatment is applied to the surface of the metal terminal so that a corrosion-resistant film is formed on the surface of the metal terminal. Here, the corrosion-resistant film refers to a thin film that provides corrosion resistance (e.g., acid resistance, alkali resistance, etc.) to the barrier layer by performing corrosion prevention treatments on the surface of the barrier layer, such as hot water modification treatment such as boehmite treatment, chemical conversion treatment, anodizing treatment, plating treatment with nickel or chromium, or coating agent application. Specifically, the corrosion-resistant film means a film that improves the acid resistance of the barrier layer (acid-resistant film), a film that improves the alkali resistance of the barrier layer (alkali-resistant film), etc. One type of treatment may be performed to form the corrosion-resistant film, or two or more types may be combined. Furthermore, it is possible to have multiple layers instead of just one. In addition, among these treatments, hot water modification treatment and anodizing treatment are treatments that dissolve the surface of the metal foil with a treatment agent to form a metal compound with excellent corrosion resistance.

[0074] In this disclosure, from the viewpoint of suitably forming an insulating reinforcement portion in the resin layer A, the corrosion-resistant coating on the metal terminal is preferably chromium-free, more preferably metal-free, and preferably formed of organic components. Specific examples of chemical conversion treatments for forming such a corrosion-resistant coating include chemical conversion treatments using a chemical conversion solution that does not contain metals such as chromium and contains polyacrylic acid, at least one of polyethylene glycol and polypropylene glycol, and ammonia (furthermore, at least one poly(meth)acrylic acid ester such as methyl polyacrylate, ethyl polyacrylate, polymethyl methacrylate, or polyethyl methacrylate may be included). Metals such as chromium contained in the corrosion-resistant coating may hinder the formation of an insulating reinforcement portion in the resin layer A.

[0075] The thickness of the corrosion-resistant coating on the metal terminals is preferably about 50 nm or more, more preferably about 70 nm or more, even more preferably about 90 nm or more, even more preferably about 100 nm or more, and also preferably about 500 nm or less, more preferably about 200 nm or less, even more preferably about 150 nm or less. Preferred ranges include about 50 to 500 nm, about 50 to 200 nm, about 50 to 150 nm, about 70 to 500 nm, about 70 to 200 nm, about 70 to 150 nm, about 90 to 500 nm, about 90 to 200 nm, about 90 to 150 nm, about 100 to 500 nm, about 100 to 200 nm, and about 100 to 150 nm.

[0076] The adhesion promoter layer 13 is a layer provided as needed for the purpose of firmly bonding the intermediate layer 11 to the first resin layer 12a and the intermediate layer 11 to the second resin layer 12b (see Figure 7). The adhesion promoter layer 13 may be provided on only one side between the intermediate layer 11 and the first resin layer 12a and the second resin layer 12b, or it may be provided on both sides.

[0077] 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 promoters. From the viewpoint of obtaining strong adhesion strength, it is preferable that the layer be formed using an isocyanate-based adhesion promoter. Among isocyanate-based adhesion promoters, those consisting of an isocyanate component selected from triisocyanate monomer and polymeric MDI exhibit excellent laminate strength and less reduction in laminate strength at high temperatures. In particular, it is especially preferable to form the adhesion promoter consisting of triphenylmethane-4,4',4"-triisocyanate, which is a triisocyanate monomer, or polymethylene polyphenyl polyisocyanate (NCO content of about 30%, viscosity of 200 to 700 mPa·s), which is a polymeric MDI. It is also preferable to form the adhesion promoter using tris(p-isocyanatephenyl)thiophosphate, which is a triisocyanate monomer, or a two-component curing type adhesion promoter mainly composed of polyethyleneimine and polycarbodiimide as a crosslinking agent.

[0078] The adhesion promoter layer 13 can be formed by applying and drying it using known coating methods such as bar coating, roll coating, or gravure coating. The amount of adhesion promoter to apply is 20 to 100 mg / m² in the case of an adhesion promoter consisting of triisocyanate. 2 The amount, preferably 40 to 60 mg / m² 2 The concentration is approximately 40-150 mg / m², and in the case of adhesion promoters consisting of polymeric MDI, it is approximately 40-150 mg / m². 2 Preferably, 60 to 100 mg / m² 2 In the case of a two-component curing type adhesion promoter that uses polyethyleneimine as the main component and polycarbodiimide as a crosslinking agent, the dosage is approximately 5 to 50 mg / m². 2 Preferably, 10 to 30 mg / m² 2 It is to that extent. Note that triisocyanate monomer is a monomer having three isocyanate groups in one molecule, and polymeric MDI is a mixture of MDI and MDI oligomers obtained by polymerizing MDI, and is represented by the following formula.

[0079]

[0080] The total thickness of the adhesive member 1 for metal terminals of this disclosure is preferably about 50 μm or more, more preferably about 80 μm or more, and even more preferably about 100 μm or more, from the viewpoint of suitably exhibiting the effects of this disclosure. Also, from the same viewpoint, the thickness is preferably about 500 μm or less, more preferably about 300 μm or less, and even more preferably about 200 μm or less. Furthermore, the preferred range of the thickness is about 50 to 500 μm, about 50 to 300 μm, about 50 to 200 μm, about 80 to 500 μm, about 80 to 300 μm, about 80 to 200 μm, about 100 to 500 μm, about 100 to 300 μm, and about 100 to 200 μm.

[0081] Furthermore, as described above, the adhesive member 1 for metal terminals of this disclosure can also constitute a cover 36 or frame 37 of an energy storage device (see Figures 12 and 13). As shown in Figure 12, when the adhesive member 1 for metal terminals of this disclosure constitutes a cover 36 of an energy storage device, the shape of the adhesive member 1 for metal terminals of this disclosure only needs to be such that it can close the opening of the cylindrical exterior material 3 for the energy storage device, and its size is designed according to the size of the opening, etc. When the adhesive member 1 for metal terminals of this disclosure constitutes the cover 36 of a power storage device, the thickness of the adhesive member 1 for metal terminals (i.e., the thickness of the cover 36 in the direction toward the power storage device element) is, from the viewpoint of adhesion between the exterior material 3 for the power storage device and the metal terminal 2, for example, 0.3 mm or more, preferably 1 mm or more, more preferably 3 mm or more, for example, 10 mm or less, preferably 8 mm or less, more preferably 7 mm or less, and preferred ranges include approximately 0.3 to 10 mm, approximately 0.3 to 8 mm, approximately 0.3 to 7 mm, approximately 1 to 10 mm, approximately 1 to 8 mm, approximately 1 to 7 mm, approximately 3 to 10 mm, approximately 3 to 8 mm, and approximately 3 to 7 mm.

[0082] Furthermore, as shown in Figure 13, when the adhesive member 1 for metal terminals of this disclosure constitutes the frame 37 of the energy storage device, the shape of the adhesive member 1 for metal terminals of this disclosure only needs to be such that it can fill the gap between the cylindrical exterior material 3 for the energy storage device and the lid 36, and its size is designed according to the size of the opening, etc. When the adhesive member 1 for metal terminals of this disclosure constitutes the frame 37 of the energy storage device, the thickness of the adhesive member 1 for metal terminals (i.e., the thickness of the frame 37 in the direction toward the energy storage device element) is, from the viewpoint of adhesion between the exterior material 3 for the energy storage device and the cover 36 (metal terminals), for example, 0.3 mm or more, preferably 1 mm or more, more preferably 3 mm or more, for example, 10 mm or less, preferably 8 mm or less, more preferably 7 mm or less, and preferred ranges include approximately 0.3 to 10 mm, approximately 0.3 to 8 mm, approximately 0.3 to 7 mm, approximately 1 to 10 mm, approximately 1 to 8 mm, approximately 1 to 7 mm, approximately 3 to 10 mm, approximately 3 to 8 mm, and approximately 3 to 7 mm.

[0083] The adhesive member 1 for metal terminals of this disclosure can be formed into a film using a resin (homopolybutylene terephthalate) that forms the resin layer A, by known methods such as extrusion lamination, T-die method, inflation method, and thermal lamination method. In the case of a multi-layer structure, each layer may be laminated using a co-extrusion type extruder, or, in the case of laminating the intermediate layer 11, the first resin layer 12a, and the second resin layer 12b via an adhesion promoter layer 13, for example, the adhesion promoter constituting the adhesion promoter layer 13 may be applied and dried on the intermediate layer 11 using the method described above, and the first resin layer 12a and the second resin layer 12b may be laminated on top of the adhesion promoter layer 13.

[0084] There are no particular limitations on the method of interposing the adhesive member 1 for metal terminals between the metal terminals 2 and the outer casing material 3 for the energy storage device. For example, as shown in Figures 1 to 3, the adhesive member 1 for metal terminals may be placed on the metal terminals 2 in the portion where the metal terminals 2 are sandwiched by the outer casing material 3 for the energy storage device. Although not shown, the adhesive member 1 for metal terminals may also be placed on both sides of the metal terminals 2 so as to cross both metal terminals 2 in the portion where the metal terminals 2 are sandwiched by the outer casing material 3 for the energy storage device.

[0085] [Metal Terminal 2] The adhesive member 1 for metal terminals of this disclosure is used interposed between the metal terminal 2 and the exterior material 3 for the energy storage device. The metal terminal 2 (tab) is a conductive member electrically connected to the electrode (positive or negative electrode) of the energy storage device element 4, and is made of a metallic material. The metallic material constituting the metal terminal 2 is not particularly limited and includes, for example, aluminum, nickel, and copper. For example, the metal terminal 2 connected to the positive electrode of a lithium-ion energy storage device is usually made of aluminum or the like. The metal terminal 2 connected to the negative electrode of a lithium-ion energy storage device is usually made of copper, nickel, etc., and from the viewpoint of low resistance and prevention of surface degradation, it is made of nickel-plated copper or nickel-copper clad material.

[0086] From the viewpoint of improving electrolyte resistance, the surface of the metal terminal 2 is preferably treated with a chemical conversion treatment. Furthermore, as described above, in this disclosure, in order to suitably form an insulating reinforcement portion in the resin layer A, it is preferable that the surface of the metal terminal is treated with a chemical conversion treatment and a corrosion-resistant film is formed on the surface of the metal terminal. From the viewpoint of suitably forming an insulating reinforcement portion in the resin layer A, it is preferable that the corrosion-resistant film on the metal terminal does not contain chromium, more preferably does not contain metal, and is preferably formed of organic components. Specific examples of chemical conversion treatments for forming such a corrosion-resistant film include chemical conversion treatments using a chemical conversion solution that does not contain metals such as chromium and contains polyacrylic acid, at least one of polyethylene glycol and polypropylene glycol, and ammonia. Metals such as chromium contained in the corrosion-resistant film may hinder the formation of an insulating reinforcement portion in the resin layer A.

[0087] The size of the metal terminal 2 can be appropriately set according to the size of the energy storage device used. The thickness of the metal terminal 2 is preferably about 50 to 1000 μm, more preferably about 70 to 800 μm. The length of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm. The width of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm.

[0088] [Exterior material 3 for energy storage device] An example of an exterior material 3 for an energy storage device is one having a laminated structure consisting of a laminate having at least a base layer 31, a barrier layer 33, and a heat-fusible resin layer 35 in that order. Figure 8 shows an example of the cross-sectional structure of the exterior material 3 for an energy storage device, in which a base layer 31, an adhesive layer 32 provided as needed, a barrier layer 33, an adhesive layer 34 provided as needed, and a heat-fusible resin layer 35 are laminated in that order. In the exterior material 3 for an energy storage device, the base layer 31 is the outer layer and the heat-fusible resin layer 35 is the innermost layer. When assembling the energy storage device, the heat-fusible resin layers 35 located on the periphery of the energy storage device element 4 are brought into contact with each other and heat-fused to seal the energy storage device element 4, thereby sealing the energy storage device element 4. Figures 1 to 3 illustrate a power storage device 10 using an embossed type outer material 3 formed by embossing or the like; however, the outer material 3 for the power storage device may be an unformed pouch type. Pouch types include three-sided seal, four-sided seal, and pillow type; any type is acceptable.

[0089] The thickness of the laminate constituting the exterior material 3 for energy storage devices is not particularly limited, but from the viewpoint of cost reduction and improvement of energy density, for example, it can be about 300 μm or less, preferably about 250 μm or less, about 210 μm or less, about 190 μm or less, about 180 μm or less, about 155 μm or less, or about 120 μm or less. Furthermore, from the viewpoint of maintaining the function of the exterior material for energy storage devices, which is to protect the energy storage device elements, the thickness of the laminate constituting the exterior material 3 for energy storage devices can be preferably about 35 μm or more, about 45 μm or more, about 60 μm or more, about 155 μm or more, or about 190 μm or more. Furthermore, the preferred range for the laminate constituting the outer material 3 for the energy storage device is, for example, approximately 35 to 300 μm, approximately 35 to 250 μm, approximately 35 to 210 μm, approximately 35 to 190 μm, approximately 35 to 180 μm, approximately 35 to 155 μm, approximately 35 to 120 μm, approximately 45 to 300 μm, approximately 45 to 250 μm, approximately 45 to 210 μm, approximately 45 to 190 μm, approximately 45 to 180 μm, approximately 45 to 155 μm, approximately 45 to 120 μm, approximately 60 to 300 μm, approximately 60 to 250 μm, and 60 to Examples of suitable thicknesses include approximately 210 μm, 60-190 μm, 60-180 μm, 60-155 μm, 60-120 μm, 155-300 μm, 155-250 μm, 155-210 μm, 155-190 μm, 155-180 μm, 190-300 μm, 190-250 μm, and 190-210 μm. In particular, when creating lightweight thin films for energy storage devices, approximately 60-155 μm is preferred, and when improving moldability, approximately 155-190 μm is preferred.

[0090] Furthermore, the adhesive member 1 for metal terminals of this disclosure can be suitably applied to the exterior material for all-solid-state batteries. The thickness of the laminate constituting the exterior material for all-solid-state batteries is not particularly limited, but from the viewpoint of cost reduction and energy density improvement, it is preferably about 10,000 μm or less, about 8,000 μm or less, and about 5,000 μm or less. From the viewpoint of maintaining the function of the exterior material for all-solid-state batteries, which is to protect the battery elements, it is preferably about 100 Examples of preferred ranges include μm or more, approximately 150 μm or more, and approximately 200 μm or more. Preferred ranges include, for example, approximately 100 to 10000 μm, approximately 100 to 8000 μm, approximately 100 to 5000 μm, approximately 150 to 10000 μm, approximately 150 to 8000 μm, approximately 150 to 5000 μm, approximately 200 to 10000 μm, approximately 200 to 8000 μm, and approximately 200 to 5000 μm, with a particular preference of approximately 100 to 5000 μm.

[0091] (Base layer 31) In the exterior material 3 for the energy storage device, the base layer 31 is a layer that functions as the base material for the exterior material for the energy storage device and is the layer that forms the outermost layer.

[0092] The material forming the base layer 31 is not particularly limited, as long as it possesses insulating properties. Examples of materials for forming the base layer 31 include polyester, polyamide, epoxy, acrylic, fluororesin, polyurethane, silicon resin, phenol, polyetherimide, polyimide, and mixtures or copolymers thereof. Polyesters such as polyethylene terephthalate have excellent electrolyte resistance and are less prone to whitening when exposed to electrolyte, making them suitable for use as a material for forming the base layer 31. Polyamide films also have excellent stretchability, which can prevent whitening due to resin cracking of the base layer 31 during molding, making them suitable for use as a material for forming the base layer 31.

[0093] The base layer 31 may be formed from a uniaxially or biaxially stretched resin film, or from an unstretched resin film. Among these, uniaxially or biaxially stretched resin films, and especially biaxially stretched resin films, are suitable for use as the base layer 31 because their heat resistance is improved by oriented crystallization.

[0094] Among these, nylon, polyester, and more preferably biaxially oriented nylon and biaxially oriented polyester are used as the resin film forming the base layer 31. Furthermore, since all-solid-state batteries are required to withstand temperatures of 150°C or higher, they are often sealed at high temperatures of 200°C or higher, making biaxially oriented polyester the most suitable.

[0095] The base layer 31 can also be constructed by laminating resin films of different materials to improve pinhole resistance and insulation when used as packaging for energy storage devices. Specifically, examples include a multilayer structure in which polyester film and nylon film are laminated, or a multilayer structure in which biaxially oriented polyester and biaxially oriented nylon are laminated. When the base layer 31 is a multilayer structure, each resin film may be bonded via an adhesive, or it may be laminated directly without an adhesive. When bonding without an adhesive, examples include bonding in a thermally molten state such as co-extrusion, sand lamination, or thermal lamination. For the above high-temperature sealing, it is desirable that at least the outermost layer be biaxially oriented polyester.

[0096] Furthermore, the base layer 31 may be made friction-reducing to improve moldability. When the base layer 31 is made friction-reducing, there are no particular restrictions on the coefficient of friction of its surface, but for example, it can be 1.0 or less. Examples of ways to make the base layer 31 friction-reducing include mat treatment, formation of a thin film layer of a slip agent, and combinations thereof.

[0097] The thickness of the base layer 31 can be, for example, about 10 to 50 μm, preferably about 15 to 30 μm.

[0098] (Adhesive layer 32) In the exterior material 3 for the energy storage device, the adhesive layer 32 is a layer that is placed on the base material layer 31 as needed in order to provide adhesion to the base material layer 31. That is, the adhesive layer 32 is provided between the base material layer 31 and the barrier layer 33.

[0099] The adhesive layer 32 is formed by an adhesive capable of bonding the base 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. Furthermore, the bonding mechanism of the adhesive used to form the adhesive layer 32 is not particularly limited and may be a chemical reaction type, solvent evaporation type, thermal melting type, hot pressure type, etc.

[0100] As for the resin component of the adhesive that can be used to form the adhesive layer 32, from the viewpoint of having excellent ductility, durability under high humidity conditions, yellowing suppression effect, and heat degradation suppression effect during heat sealing, and effectively suppressing the occurrence of delamination by suppressing the decrease in laminate strength between the base layer 31 and the barrier layer 33, two-component curable polyurethane adhesives; polyamide, polyester, or blended resins of these with modified polyolefins are preferred.

[0101] Furthermore, the adhesive layer 32 may be multilayered with different adhesive components. When the adhesive layer 32 is multilayered with different adhesive components, from the viewpoint of improving the lamination strength between the base material layer 31 and the barrier layer 33, it is preferable to select a resin with excellent adhesion to the base material layer 31 as the adhesive component arranged on the base material layer 31 side, and an adhesive component with excellent adhesion to the barrier layer 33 as the adhesive component arranged on the barrier layer 33 side. Specifically, when the adhesive layer 32 is multilayered with different adhesive components, preferred adhesive components arranged on the barrier layer 33 side include acid-modified polyolefins, metal-modified polyolefins, mixed resins of polyester and acid-modified polyolefins, and resins containing copolymerized polyesters.

[0102] The thickness of the adhesive layer 32 can be, for example, about 2 to 50 μm, preferably about 3 to 25 μm.

[0103] (Barrier layer 33) In the exterior material for energy storage devices, the barrier layer 33 is a layer that has the function of improving the strength of the exterior material for energy storage devices and preventing water vapor, oxygen, light, etc. from entering the inside of the energy storage device. The barrier layer 33 is preferably a metal layer, that is, a layer made of metal. Specifically, examples of metals that make up the barrier layer 33 include aluminum, stainless steel, and titanium, with aluminum being preferred. The barrier layer 33 can be formed from, for example, metal foil, metal vapor-deposited film, inorganic oxide vapor-deposited film, carbon-containing inorganic oxide vapor-deposited film, or a film provided with these vapor-deposited films, and it is preferably formed from metal foil, and more preferably from aluminum foil. From the viewpoint of preventing wrinkles and pinholes from occurring in the barrier layer 33 during the manufacturing of the exterior material for energy storage devices, it is more preferable to form the barrier layer from 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), hard aluminum foil, or aluminum foil assigned a JIS standard number in the 5000s (for example, magnesium-converted aluminum foil such as A5052 and A5005).

[0104] In the barrier layer 33, the layer composed of the aforementioned metal material may include recycled metal material. Examples of recycled metal material include recycled aluminum alloy, stainless steel, titanium steel, or steel sheet. These recycled materials can each be obtained by known methods. Recycled aluminum alloy can be obtained, for example, by the manufacturing method described in International Publication No. 2022 / 092231. The barrier layer 33 may be composed solely of recycled material, or it may be composed of a mixture of recycled material and virgin material. Recycled metal material refers to metal material that has been recovered, isolated, and refined from various products used in the market or waste generated from manufacturing processes to make it reusable. Virgin metal material refers to new metal material refined from natural metal resources (raw materials) and is not recycled material.

[0105] Regarding the thickness of the barrier layer 33, from the viewpoint of making the exterior material for the energy storage device thinner while also making it difficult for pinholes to occur during molding, it is preferably about 10 to 200 μm, more preferably about 20 to 100 μm, about 20 to 45 μm, about 45 to 65 μm, or about 65 to 85 μm.

[0106] Furthermore, it is preferable that at least one surface, preferably both surfaces, of the barrier layer 33 is chemically treated to stabilize adhesion and prevent dissolution and corrosion. Here, chemical treatment refers to a treatment that forms a corrosion-resistant film on the surface of the barrier layer.

[0107] (Adhesive layer 34) In the exterior material 3 for the energy storage device, the adhesive layer 34 is a layer provided between the barrier layer 33 and the heat-fusible resin layer 35 as needed in order to firmly bond the heat-fusible resin layer 35.

[0108] The adhesive layer 34 is formed by an adhesive capable of bonding the barrier layer 33 and the heat-fusible resin layer 35. The composition of the adhesive used to form the adhesive layer is not particularly limited, but examples include adhesives composed of a polyester polyol compound and an alicyclic isocyanate compound.

[0109] The thickness of the adhesive layer 34 can be, for example, about 1 to 40 μm, preferably about 2 to 30 μm.

[0110] (Heat-fusible resin layer 35) In the exterior material 3 for the energy storage device, the heat-fusible resin layer 35 is the innermost layer and is a layer that seals the energy storage device elements by heat-fussing the heat-fusible resin layers together during the assembly of the energy storage device.

[0111] The resin component used in the heat-fusible resin layer 35 is not particularly limited as long as it is heat-fusible, but for example, in the case of exterior materials for energy storage devices, polyolefins and cyclic polyolefins are generally used.

[0112] Specifically, the polyolefins include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; crystalline or amorphous polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymer of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymer of propylene and ethylene); and ethylene-butene-propylene terpolymers. Among these polyolefins, polyethylene and polypropylene are preferred.

[0113] The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of olefins that are constituent monomers of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, isoprene, and the like. Examples of cyclic monomers that are constituent monomers of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, examples of cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkenes are preferred, and norbornene is more preferred. Styrene can also be used as a constituent monomer.

[0114] Among these resin components, preferred are crystalline or amorphous polyolefins, cyclic polyolefins, and blends thereof; more preferably, polyethylene, polypropylene, copolymers of ethylene and norbornene, and blends of two or more of these.

[0115] The heat-fusible resin layer 35 may be formed by a single resin component, or by a blended polymer combining two or more resin components. Furthermore, the heat-fusible resin layer 35 may be formed as a single layer, or it may be formed as two or more layers made of the same or different resin components.

[0116] Furthermore, the thickness of the heat-sealable resin layer 35 is not particularly limited, but is preferably about 2 to 2000 μm, more preferably about 5 to 1000 μm, and more preferably about 10 to 500 μm.

[0117] Furthermore, the adhesive member 1 for metal terminals of this disclosure can be particularly suitably applied to exterior materials for all-solid-state batteries, and the melting point of the heat-fusible resin layer 35 of the exterior 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.

[0118] Furthermore, examples of resins included in the heat-sealable resin layer 35 of the exterior material for all-solid-state batteries 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 exterior material for all-solid-state batteries, the heat-sealable resin layer 35 is preferably formed from a polybutylene terephthalate film. In addition, because the heat-sealable resin layer 35 is formed from a polybutylene terephthalate film, the adhesion to the resin layer A of the adhesive member 1 for metal terminals of this 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, or the resin forming the polybutylene terephthalate film may be melt-extruded to form a film and then laminated with the adhesive layer 34.

[0119] The polybutylene terephthalate film may be an stretched polybutylene terephthalate film or an unstretched polybutylene terephthalate film, and an unstretched polybutylene terephthalate film is preferred.

[0120] The polybutylene terephthalate film is preferably composed of at least one of homopolybutylene terephthalate and copolymerized polybutylene terephthalate.

[0121] The heat-sealable resin layer 35 may be formed as a single layer, or it may be formed as two or more layers of the same or different resins. When the heat-sealable resin layer 35 is formed as two or more layers, at least one layer is preferably made of polybutylene terephthalate film, and the polybutylene terephthalate film is preferably the innermost layer of the exterior material for the all-solid-state battery. Furthermore, the layer that adheres to the adhesive layer 34 is preferably made of polybutylene terephthalate film. When the heat-sealable resin layer 35 is formed as two or more layers, the layer not made of polybutylene terephthalate film may be made of, for example, polyolefins such as polypropylene and polyethylene, or acid-modified polyolefins such as acid-modified polypropylene and acid-modified polyethylene. However, since polyolefins and acid-modified polyolefins have lower durability in high-temperature environments compared to polybutylene terephthalate or polyethylene terephthalate, it is preferable that the heat-sealable resin layer 35 is composed solely of a polybutylene terephthalate film such as a homo-PBT layer or a copolymerized PBT layer, or solely of polyethylene terephthalate such as a PET layer.

[0122] Furthermore, it is preferable that the resin layer A forming the surface of the metal terminal adhesive member 1 on the exterior material side for the energy storage device and the resin constituting the heat-fusible resin layer 35 are the same. When we say that the resin layer A forming the surface of the metal terminal adhesive member 1 on the exterior material side for the energy storage device and the resin constituting the heat-fusible resin layer 35 are the same, it means that, for example, 80% or more by mass of the components in these resins are the same, 90% or more by mass are the same, 95% or more by mass are the same, or 100% by mass are the same.

[0123] 2. Energy Storage Device The energy storage device 10 of this disclosure comprises at least an energy storage device element 4 having a positive electrode, a negative electrode, and an electrolyte; an outer casing material 3 for the energy storage device that seals the energy storage device element 4; and metal terminals 2 that are electrically connected to the positive electrode and the negative electrode, respectively, for electrically connecting the outside of the energy storage device 10 to the energy storage device element 4.

[0124] In the energy storage device 10 of this disclosure, an adhesive member 1 for metal terminals is interposed between a metal terminal 2 and an exterior material 3 for the energy storage device. The adhesive member 1 for metal terminals includes a resin layer A that constitutes at least one surface of the adhesive member 1 for metal terminals, and an insulating reinforcement portion is formed on at least a part of the resin layer A of the adhesive member 1 for metal terminals. The insulating reinforcement portion is a layer in which no peak top is detected in nano-TA measurement from the surface using an atomic force microscope, in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A. The energy storage device 10 of this disclosure can be obtained, for example, by interposing the adhesive member 1 for metal terminals of this disclosure between a metal terminal 2 and an exterior material 3 for the energy storage device. That is, the energy storage device 10 of this disclosure can be manufactured by a method that includes the step of interposing the adhesive member 1 for metal terminals of this disclosure between a metal terminal 2 and an exterior material 3 for the energy storage device.

[0125] In the energy storage device 10 of this disclosure, it is sufficient that an insulating reinforcement portion is formed on at least a part of the resin layer A of the adhesive member 1 for metal terminals. In the manufacturing process of the energy storage device 10 of this disclosure, it is not necessary to heat-seal the resin layer A of the adhesive member for metal terminals to the metal terminals (aluminum alloy foil having a corrosion-resistant coating on its surface formed by a chemical conversion treatment solution in which a 7% aqueous solution of polyacrylic acid (weight average molecular weight 250,000) and a 10% aqueous solution of polyethylene glycol (weight average molecular weight 360 to 440) is used, in a metal head flat plate press machine with a 2.0 mm thick, hardness 30 silicone rubber attached, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds. The metal terminals may be heat-sealed under other conditions.

[0126] In this disclosure, for example, an energy storage device element 4 having at least a positive electrode, a negative electrode, and an electrolyte is covered with an energy storage device exterior material 3, with the metal terminals 2 connected to the positive electrode and the negative electrode respectively protruding outwards, and the metal terminal adhesive member 1 of this disclosure interposed between the metal terminals 2 and the heat-sealable resin layer 35, so that a flange portion of the energy storage device exterior material (a region where the heat-sealable resin layers 35 come into contact with each other, and the peripheral edge portion 3a of the energy storage device exterior material) is formed around the periphery of the energy storage device element 4, and the heat-sealable resin layers 35 of the flange portion are heat-sealed to create a sealed energy storage device 10 using the energy storage device exterior material 3.

[0127] The adhesive member 1 for metal terminals and the metal terminal 2 can be pre-heat-fused together, and the adhesive member for metal terminals can be attached to the metal terminal, resulting in a metal terminal with an adhesive member attached, which can then be used in the manufacture of energy storage devices.

[0128] When housing an energy storage device element 4 using an outer casing material 3 for energy storage devices, the heat-sealable resin layer 35 of the outer casing material 3 is used so that it faces inward (the surface in contact with the energy storage device element 4). Furthermore, if the innermost and outermost layers of the outer casing material for energy storage devices are heat-sealable resin layers, the packaging may be formed by heat-sealing the innermost heat-sealable resin layer and the outermost heat-sealable resin layer.

[0129] The energy storage device element may be sealed by a lid in addition to the energy storage device casing material. That is, the energy storage device casing material and the lid constitute an casing that seals the energy storage device element (an casing for the energy storage device). For example, the energy storage device element may be housed inside a cylindrical energy storage device casing material, and the opening may be closed with a lid. In another example, the energy storage device element, connected to a lid, may be housed inside a cylindrical energy storage device casing material that has an opening, and the opening may be closed with a lid. It is preferable that the lid and the energy storage device casing material are joined by any means. From the viewpoint of reducing dead space between the energy storage device element and the energy storage device casing material in order to improve the volumetric energy density of the energy storage device, it is preferable that the energy storage device casing material is wrapped around the energy storage device element and the lid.

[0130] The casing material for energy storage devices of this disclosure can be suitably used in energy storage devices such as batteries (including capacitors, capacitors, etc.). Furthermore, the casing material for energy storage devices of this disclosure can be used in either primary batteries or secondary batteries, but is preferably used in secondary batteries. The type of secondary battery to which the casing material for energy storage devices of this disclosure can be applied is not particularly limited, and examples include lithium-ion batteries, lithium-ion polymer batteries, all-solid-state batteries, semi-solid-state batteries, pseudo-solid-state batteries, polymer batteries, all-resin batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors, etc. Among these secondary batteries, lithium-ion batteries and lithium-ion polymer batteries are particularly suitable applications for the casing material for energy storage devices of this disclosure.

[0131] Among these, the adhesive member 1 for metal terminals of this disclosure can be suitably applied to all-solid-state batteries.

[0132] The present disclosure will be described in detail below with reference to examples and comparative examples. However, the present disclosure is not limited to the examples.

[0133] <Preparation of Adhesive Members for Metal Terminals> (Examples 1-4) A homopolybutylene terephthalate film (melting point 224°C, thickness 100 μm) was prepared using homopolybutylene terephthalate (homo PBT), and each single layer of the homopolybutylene terephthalate film (resin layer A) was used as an adhesive member for metal terminals.

[0134] (Example 5) A copolymerized polybutylene terephthalate film (melting point 205°C, thickness 100 μm) was prepared using copolymerized polybutylene terephthalate (copolymerized PBT), and a single layer of this copolymerized polybutylene terephthalate film (resin layer A) was used as an adhesive member for metal terminals. Copolymerized polybutylene terephthalate has two constituent units: terephthalic acid, which forms the main component polybutylene terephthalate structure, and 1,4-butanediol. Furthermore, dodecanediic acid is block polymerized as a minor component to the polybutylene terephthalate structure. Copolymerized polybutylene terephthalate contains 12% by mass of dodecanediic acid.

[0135] (Example 6) A copolymerized polybutylene terephthalate film (melting point 215°C, thickness 100 μm) was prepared using copolymerized polybutylene terephthalate (copolymerized PBT), and a single layer of this copolymerized polybutylene terephthalate film (resin layer A) was used as an adhesive member for metal terminals. Copolymerized polybutylene terephthalate is a copolymer in which terephthalic acid, which forms the main component polybutylene terephthalate structure, and 1,4-butanediol form two constituent units, and furthermore, polytetramethylene glycol is introduced as a diol component to the polybutylene terephthalate structure, substituting a portion of the 1,4-butanediol. Copolymerized polybutylene terephthalate contains 5% by mass of polytetramethylene glycol as a monomer unit.

[0136] (Example 7) A polyethylene terephthalate film (melting point 260°C, thickness 100 μm) made of polyethylene terephthalate (PET) was prepared, and a single layer of the polyethylene terephthalate film (resin layer A) was used as an adhesive member for metal terminals.

[0137] (Comparative Example 1) The same adhesive member for metal terminals as in Examples 1-4 was used, and in the preparation of metal terminals with adhesive members for metal terminals described later, a corrosion-resistant coating E or a corrosion-resistant coating F was formed on the surface of the metal terminals, and these were designated as Comparative Example 1 (see Table 1).

[0138] (Comparative Example 2) The same adhesive member for metal terminals as in Example 5 was used, and in the preparation of metal terminals with adhesive member for metal terminals described later, a corrosion-resistant coating E or a corrosion-resistant coating F was formed on the surface of the metal terminals, and these were designated as Comparative Example 2 (see Table 1).

[0139] (Comparative Example 3) The same adhesive member for metal terminals as in Example 6 was used, and in the preparation of metal terminals with adhesive member for metal terminals described later, a corrosion-resistant coating E or a corrosion-resistant coating F was formed on the surface of the metal terminals, and these were designated as Comparative Example 3 (see Table 1).

[0140] (Comparative Example 4) The same adhesive member for metal terminals as in Example 7 was used, and in the preparation of metal terminals with adhesive member for metal terminals described later, a corrosion-resistant coating E or a corrosion-resistant coating F was formed on the surface of the metal terminals, and these were designated as Comparative Example 4 (see Table 1).

[0141] (Comparative Example 5) A laminated film was prepared by combining a maleic anhydride-modified polypropylene film (PPa, melting point 162°C, thickness 50 μm) and a polypropylene film (PP, melting point 160°C, thickness 50 μm), and this laminated film was used as an adhesive member for metal terminals. In the preparation of metal terminals with adhesive members described later, a corrosion-resistant coating E or a corrosion-resistant coating F was formed on the surface of the metal terminal, and these were designated as Comparative Example 5 (see Table 1).

[0142] [Preparation of Metal Terminals with Adhesive Components for Metal Terminals] Two types of metal terminals were prepared: aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) and nickel-plated copper foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm). Next, six types of corrosion-resistant coatings A, B, C, D, E, and F were formed on the surface of the metal terminals to prepare metal terminals with corrosion-resistant coatings (a total of nine types). Specifically, the surface of each metal terminal was subjected to chemical conversion treatment using chemical conversion treatment solutions A, B, C, D, E, and F to form corrosion-resistant coatings A, B, C, D, E, and F (thickness 100 nm), thereby preparing metal terminals A, B, C, D, E, and F with corrosion-resistant coatings. Details of chemical conversion treatment solutions A, B, C, D, E, and F are described below. Next, two pieces of adhesive material for metal terminals, stored in a dry room (23°C, dew point temperature -40°C) for more than 24 hours, were cut to a size of TD (width) 10 mm x MD (length) 55 mm. The MD of these two pieces of adhesive material for metal terminals and the MD of each corrosion-resistant coated metal terminal were positioned perpendicular to each other. Silicone rubber with a thickness of 2.0 mm and a hardness of 30 was attached to both sides of each corrosion-resistant coated metal terminal 10 mm from the edge. The metal terminals were then heat-sealed in a flat plate press with a metal head at a temperature of 260°C, a pressure of 1 MPa (surface pressure on the silicone rubber), and for 13 seconds. This process prepared a metal terminal with adhesive material for metal terminals, in which the adhesive material for metal terminals, each corrosion-resistant coated metal terminal, and the adhesive material for metal terminals were layered in that order. However, in the case of Comparative Example 5, since the melting point of the film was lower compared to the example, a metal terminal with an adhesive member for metal terminals was prepared under the conditions of a temperature of 190°C, a pressure of 0.20 MPa (surface pressure applied to the silicone rubber), and a heat sealing process for 16 seconds. In the laminated film of Comparative Example 5, the surface of the maleic anhydride-modified polypropylene film of the laminated film was positioned to contact the metal terminal and then heat-sealed.

[0143] Chemical treatment solution A is a treatment solution prepared by mixing a 7% aqueous solution of polyacrylic acid (weight-average molecular weight approximately 250,000, kinematic viscosity (10%, 25℃) 400 mPa·s to 1000 mPa·s, CAS No. 9003-01-4) manufactured by Fujifilm Wako Pure Chemical Industries, with a 10% aqueous solution of polyethylene glycol (weight-average molecular weight 400) manufactured by Fujifilm Wako Pure Chemical Industries, in a mass ratio of polyacrylic acid aqueous solution: polyethylene glycol aqueous solution: 28% ammonia water = 1:1:1. - Chemical treatment solution B is a treatment solution prepared by mixing a 7% aqueous solution of polyacrylic acid (weight-average molecular weight approximately 250,000, kinematic viscosity (10%, 25℃) 400 mPa·s to 1000 mPa·s, CAS No. 9003-01-4) manufactured by Fujifilm Wako Pure Chemical Industries with a 10% aqueous solution of polypropylene glycol, diol type (weight-average molecular weight approximately 2000) manufactured by Fujifilm Wako Pure Chemical Industries, in a ratio of polyacrylic acid aqueous solution:polypropylene glycol aqueous solution:28% ammonia water = 1:1:1. - Chemical treatment solution C is a treatment solution that does not contain metals such as chromium, and contains polyacrylic acid, polypropylene glycol, and ammonia. - Chemical treatment solution D is a treatment solution that does not contain metals such as chromium, and contains polyacrylic acid, polypropylene glycol, ammonia, and (meth)acrylic acid ester. - Chemical treatment solution E is a zirconium-based treatment agent. Chemical treatment solution F is a treatment solution consisting of three components: phenolic resin, chromium(III) fluoride compound, and phosphoric acid.

[0144] The insulation reinforcement portion was observed using a laser microscope as follows. A sample was obtained by cutting the portion of the metal terminal with adhesive material for metal terminals, which was prepared in the above-mentioned [Preparation of Metal Terminals with Adhesive Material for Metal Terminals], where the adhesive material is heat-fused to the metal terminal, in the thickness direction Z. The sample size includes the metal terminal. In the Z direction, the entire laminate of adhesive material for metal terminals / metal terminal / adhesive material for metal terminals in the sample may be cut in the thickness direction, or only the adhesive material for metal terminals / metal terminal portion may be cut. If the metal terminal has a thickness of 1 mm or more, the thickness of the metal terminal portion should be about 200 μm. Cutting was performed by cutting in the thickness direction with a microtome (Daiwa Koki Kogyo Co., Ltd.: REM-710 retratome). The obtained cross-section was observed with a laser microscope (Keyence Co., Ltd.: VK-9700) at an observation magnification of 50x.

[0145] [Measurement of Softening Point of Adhesive Member for Metal Terminals] Metal terminals with adhesive members for metal terminals, prepared in the above-mentioned [Preparation of Metal Terminals with Adhesive Members for Metal Terminals], were prepared. Samples were obtained by cutting the portion of the metal terminal with adhesive member for metal terminals where the adhesive member was heat-fused to the metal terminal in the thickness direction. The size of the samples was such that the lengths of TD and MD were each 1 mm or more. Next, if the metal terminal was aluminum alloy foil, the sample was immersed in a sufficient amount of 10% hydrochloric acid to dissolve the metal terminal. If the metal terminal was nickel-plated copper foil, the sample was immersed in a sufficient amount of concentrated nitric acid to dissolve the metal terminal. The adhesive members for metal terminals obtained by dissolving the metal terminals were washed with water three times, the moisture was wiped off, and they were allowed to air dry for 24 hours. Then, the softening point of the adhesive member for metal terminals was measured under the following test conditions. For the insulation reinforcement portion, the measurement was taken from the surface of the area that was in contact with the metal terminal. For resin layer A, the measurement was taken from the surface of the area that was not in contact with the metal terminal. In Examples 1-7, an insulating reinforcement portion was formed on the metal terminal side of the adhesive member for metal terminals (resin layer A) by heat fusion with the metal terminals. The softening points were measured for both the portion of resin layer A where the insulating reinforcement portion was not formed (remaining as resin layer A) and the insulating reinforcement portion. In the insulating reinforcement portion formed on the adhesive member for metal terminals (resin layer A) of Example 1-7, no peak top (i.e., softening point) was observed in the temperature range above the softening point of resin layer A and below 15°C higher than the softening point of resin layer A, and no peak top (i.e., softening point) was observed even when the temperature reached 250°C. In Comparative Example 1-5, no layer corresponding to the insulating reinforcement portion was formed in the laminated film.

[0146] (Test Conditions) The softening point was determined by nano-TA measurement using an atomic force microscope equipped with a nanothermal microscope consisting of a cantilever with a heating mechanism. An Anasys Instruments nanoTA was used as the softening point measuring device, and an Anasys Instruments PR-EX-AN2-300-5 was used as the thermal probe. The following calibration was performed before measurement. As standard samples, Bruker nanoTA Calibration Samples were prepared, with polycaprolactone (softening temperature: 55°C), polyethylene (softening temperature: 116°C), and polyethylene terephthalate (softening temperature: 235°C), all with known softening temperatures, placed on a single sample stage. Each standard sample was heated while the thermal probe was in contact with its surface. During heating, the thermal expansion directly beneath the thermal probe was measured, and a graph representing the Deflection (displacement) against Voltage (potential) was obtained. The measurement conditions set on the device were as follows: the starting voltage was 0.1V, the ending voltage was 10V, the rate was 0.2V / sec, and the Deflection setting was -4V. Using the softening temperature of each standard sample, the graph representing the displacement of the thermal probe against potential was converted into a graph representing the displacement against temperature. Calibration (n=3) was performed in the manner described above. Heating rate: 10℃ / sec Heating start temperature: 40℃ AFM measurement area: 10μm The softening point was calculated from the peak top. The average value of the values ​​obtained from three measurements with different measurement locations was adopted.

[0147] [Preparation of Exterior Materials for All-Solid-State Batteries] Five types of exterior materials for all-solid-state batteries were prepared to be used for the adhesive members for metal terminals used in Examples 1-7 and Comparative Examples 1-5. As the base layer, a polyethylene terephthalate film (25 μm) was prepared with corona treatment applied to the bonding surface. In addition, an aluminum alloy foil (JIS H4160:1994 A8021H-O, 40 μm thick) was prepared as the barrier layer.

[0148] For the heat-sealable resin layer (40 μm) of the all-solid-state battery exterior material used for the adhesive members for metal terminals prepared in Examples 1-7 and Comparative Example 1-5, the same resin as the resin constituting the adhesive members for metal terminals in Examples 1-7 and Comparative Example 1-5 was used (i.e., for the exterior material used for the adhesive members for metal terminals in Examples 1-4 and Comparative Example 1, a homopolybutylene terephthalate film (melting point 224°C, thickness 40 μm) formed from homopolybutylene terephthalate (homo PBT) was used as the heat-sealable resin layer (Exterior Material I). For the exterior material used for the adhesive members for metal terminals in Examples 5 and Comparative Example 2, a copolymerized polybutylene terephthalate film (melting point 205°C, thickness 40 μm) formed from copolymerized polybutylene terephthalate (copolymerized PBT) was used as the heat-sealable resin layer (Exterior Material II). For the heat-fusible resin layer, a copolymerized polybutylene terephthalate film (melting point 215°C, thickness 40 μm) formed from copolymerized polybutylene terephthalate (copolymerized PBT) was used (Exterior Material III). For the exterior materials used in the adhesive members for metal terminals in Example 7 and Comparative Example 4, a polyethylene terephthalate film (melting point 260°C, thickness 40 μm) formed from polyethylene terephthalate (PET) was used as the heat-fusible resin layer (Exterior Material IV). For Comparative Example 5, a polypropylene film (melting point 160°C) was used as the heat-fusible resin layer (40 μm) among the laminated films constituting the adhesive member for metal terminals (Exterior Material V). Furthermore, for the adhesive members for metal terminals in Example 4 and Comparative Example 1, insulation performance evaluations were also performed using copolymerized polybutylene terephthalate film (melting point 205°C, thickness 40 μm) as the heat-fusible resin layer of the exterior material.

[0149] Using a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound), the substrate layer and the barrier layer were bonded by dry lamination to produce a laminate consisting of a substrate layer (25 μm) / adhesive layer (3 μm) / barrier layer (40 μm). Next, in Examples 1-7 and Comparative Examples 1-4, a resin composition containing a polyester polyol compound (with a hydrolysis inhibitor added) and an alicyclic isocyanate compound (including isophorone diisocyanate) was used, and the barrier layer side of the obtained laminate was bonded to a heat-fusible resin layer by dry lamination, thereby laminating an adhesive layer (3 μm) / heat-fusible resin layer (40 μm) on top of the barrier layer. Next, the obtained laminate was aged at 80°C for 72 hours to obtain an exterior material consisting of a laminate in the following order: base layer (polyethylene terephthalate film 25 μm) / adhesive layer (cured product of two-component curable urethane adhesive 3 μm) / barrier layer (aluminum alloy foil 40 μm) / adhesive layer (cured product of a resin composition containing a polyester polyol compound and an alicyclic isocyanate compound 3 μm) / heat-fusible resin layer (40 μm). On the other hand, in Comparative Example 5, an acid-modified polypropylene film (melting point 162°C, 40 μm) and a polypropylene film (melting point 160°C, 40 μm) were laminated on top of the barrier layer by melt extrusion molding. Next, the obtained laminate was aged at 80°C for 72 hours to obtain an exterior material consisting of a laminate in the following order: base layer (polyethylene terephthalate film 25 μm) / adhesive layer (cured product of two-component urethane adhesive 3 μm) / barrier layer (aluminum alloy foil 40 μm) / adhesive layer (40 μm) / heat-fusible resin layer (40 μm). The obtained exterior material was stored in a dry room (23°C, dew point temperature -40°C) for at least 24 hours before being used for the insulation evaluation described later.

[0150] [Evaluation of Insulation] The metal terminals with adhesive members for metal terminals, prepared in the above-mentioned [Preparation of Metal Terminals with Adhesive Members for Metal Terminals], were used as test samples. In addition, as exterior materials for all-solid-state batteries to be used for the adhesive members for metal terminals prepared in Examples 1-7 and Comparative Examples 1-5, exterior materials with different heat-sealable resin layers (TD (width direction) 30 mm, MD (length direction) 150 mm) were prepared in the [Preparation of Exterior Materials for All-Solid-State Batteries] (as mentioned above, Comparative Example 5 also had a different adhesive layer).

[0151] The exterior material was folded in half lengthwise so that the heat-fusible resin layers of the exterior material faced each other, and a metal terminal with an adhesive component for metal terminals was placed between the heat-fusible resin layers. Furthermore, a stainless steel wire (diameter 170 μm, length 7 mm) was placed between the metal terminal with the adhesive component for metal terminals and the heat-fusible resin layer of the exterior material. The metal terminal with the adhesive component for metal terminals and the stainless steel wire were each placed in the center in the width direction of the exterior material. In addition, the length direction of the stainless steel wire, the length direction of the exterior material, the length direction of the metal terminal, and the TD (width direction: 10 mm) of the adhesive component for metal terminals were aligned. The side of the metal terminal with the adhesive component for metal terminals that has the adhesive component for metal terminals was placed on the folded side of the exterior material. The metal terminal with the adhesive component for metal terminals was pressed into contact with the fold of the exterior material. A stainless steel wire (7 mm in length) was installed so as not to protrude from the TD (width direction: 10 mm) of the adhesive material for metal terminals. Next, the positive terminal of the tester was connected to the metal terminal and the negative terminal to the barrier layer of the outer casing material. The tester was set to emit a continuity (short circuit) signal when the applied voltage was 100 V and the resistance was 200 MΩ or less. Next, a voltage of 100 V was applied between the testers, and with the stainless steel wire interposed between the adhesive material for metal terminals on the metal terminal and the outer casing material, a heat seal was applied perpendicular to the wire at 230°C, 1 MPa, and a width of 7 mm, and the time until a short circuit signal was emitted was measured. Five measurements were taken, and the average of the three points was used, excluding the longest and shortest points. The insulation performance was evaluated according to the following criteria. The results are shown in Table 1. A: The time until a short circuit was 5 seconds or more. C: The time until a short circuit was less than 5 seconds.

[0152]

[0153] In Table 1, AL foil refers to aluminum alloy foil that constitutes a metal terminal, and Ni-Cu foil refers to nickel-plated copper foil that constitutes a metal terminal.

[0154] As described above, this disclosure provides inventions in the following embodiments. Item 1. An adhesive member for a metal terminal interposed between a metal terminal electrically connected to an electrode of an energy storage device element and an outer casing for an energy storage device that seals the energy storage device element, wherein the adhesive member for the metal terminal includes a resin layer A that constitutes at least one surface of the adhesive member for the metal terminal, and when the resin layer A of the adhesive member for the metal terminal is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a silicone rubber with a thickness of 2.0 mm and a hardness of 30, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, an insulating reinforcement portion is formed in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by dissolving a 7% aqueous solution of polyacrylic acid (weight-average molecular weight 250,000) and a 10% aqueous solution of polyethylene glycol (weight-average molecular weight 360 to 440) in a mass ratio of polyacrylic acid aqueous solution: polyethylene glycol aqueous solution: 28% ammonia water = 1:1:1, drying it in an oven set to 150°C for 10 minutes to a film thickness of 70 nm to 150 nm. The insulating reinforcement part is an adhesive member for metal terminals in which, after completely dissolving and removing the aluminum alloy foil with 10% hydrochloric acid, the area that was in contact with the aluminum alloy foil is washed with water, and nano-TA measurement is performed on the surface using an atomic force microscope, and no peak top is detected in the range of temperature above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A. Item 2. The adhesive member for metal terminals according to Item 1, wherein the resin layer A contains polyester. Item 3. The adhesive member for metal terminals according to item 1 or 2, wherein the insulating reinforcement portion is a layer in which no peak top is detected in the range above the softening point of the resin layer A and below a temperature of 250°C in nano-TA measurement using an atomic force microscope. Item 4. The adhesive member for metal terminals according to any one of items 1 to 3, wherein the adhesive member for metal terminals is composed of a single layer or multiple layers.Item 5. A metal terminal with an adhesive member for metal terminals, wherein an adhesive member for metal terminals is attached to a metal terminal, the adhesive member for metal terminals includes a resin layer A that constitutes at least one surface of the adhesive member for metal terminals, an insulating reinforcement portion is formed on at least a part of the resin layer A of the adhesive member for metal terminals, and the insulating reinforcement portion is a layer in which no peak top is detected in nano-TA measurement using an atomic force microscope in the range of temperature above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A, the metal terminal with an adhesive member for metal terminals. Item 6. An energy storage device comprising at least a positive electrode, a negative electrode, and an electrolyte; an outer casing for the energy storage device that seals the energy storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, for electrically connecting the outside of the energy storage device to the energy storage device element, wherein an adhesive member for metal terminals is interposed between the metal terminals and the outer casing for the energy storage device, the adhesive member for metal terminals includes a resin layer A that constitutes at least one surface of the adhesive member for metal terminals, an insulating reinforcement portion is formed on at least a part of the resin layer A of the adhesive member for metal terminals, and the insulating reinforcement portion is a layer in which no peak top is detected in nano-TA measurement from the surface using an atomic force microscope in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A. Item 7. A method for manufacturing an energy storage device comprising at least a positive electrode, a negative electrode, and an electrolyte; an outer casing for the energy storage device that seals the energy storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, for electrically connecting the outside of the energy storage device to the energy storage device element, the method comprising the step of interposing an adhesive member for metal terminals described in any one of items 1 to 4 between the metal terminals and the outer casing for the energy storage device, and sealing the energy storage device element with the outer casing for the energy storage device.Item 8. A method for manufacturing an energy storage device comprising at least a positive electrode, a negative electrode, and an electrolyte; an outer casing for an energy storage device that seals the energy storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, for electrically connecting the outside of the energy storage device to the energy storage device element, the method comprising the step of sealing the energy storage device element with the outer casing for an energy storage device by interposing a metal terminal with an adhesive member for metal terminals as described in Item 5. Item 9. A kit comprising an adhesive member for metal terminals and an outer casing for an energy storage device, wherein the adhesive member for metal terminals includes a resin layer A that constitutes at least one surface of the adhesive member for metal terminals, and when the resin layer A of the adhesive member for metal terminals is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a silicone rubber with a thickness of 2.0 mm and a hardness of 30, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, an insulating reinforcement portion is formed in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water. The solution is prepared in a mass ratio of 1:1:1 for the polyacrylic acid aqueous solution, polyethylene glycol aqueous solution, and 28% ammonia water. The coating is then dried in an oven set to 150°C for 10 minutes to achieve a film thickness of 70 nm to 150 nm. The insulation reinforcement section is formed by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water. Nano-TA measurement is performed on the surface of the area that was in contact with the aluminum alloy foil using an atomic force microscope. The layer is one in which no peak top is detected in the temperature range above the softening point of resin layer A and below 15°C above the softening point of resin layer A. A kit used in which, when in use, the adhesive member for metal terminals is interposed between the metal terminals electrically connected to the electrodes of the energy storage device element and the outer casing for the energy storage device that seals the energy storage device element, thereby sealing the energy storage device element with the outer casing for the energy storage device.Item 10. A method for manufacturing an adhesive member for a metal terminal, which is interposed between a metal terminal electrically connected to the electrodes of an energy storage device element and an outer casing for an energy storage device that seals the energy storage device element, wherein the adhesive member for the metal terminal includes a resin layer A that constitutes at least one surface of the adhesive member for the metal terminal, and the resin layer A of the adhesive member for the metal terminal is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a silicone rubber with a thickness of 2.0 mm and a hardness of 30, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, thereby forming an insulating reinforcement portion in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water, and performing nano-TA measurement on the surface of the area that was in contact with the aluminum alloy foil using an atomic force microscope. The coating is formed by drying it in an oven set to 150°C for 10 minutes to a thickness of 70 nm to 150 nm. The insulating reinforcement part is formed by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water and performing nano-TA measurement on the surface of the area that was in contact with the aluminum alloy foil, and determining that the layer is one in which no peak top is detected in the range of temperature above the softening point of the resin layer A and below 15°C above the softening point of the resin layer A.Item 11. A method for manufacturing a metal terminal with an adhesive member for metal terminals, comprising the step of attaching an adhesive member for metal terminals to a metal terminal, wherein the adhesive member for metal terminals includes a resin layer A that constitutes at least one surface of the adhesive member for metal terminals, and the resin layer A of the adhesive member for metal terminals is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a silicone rubber with a thickness of 2.0 mm and a hardness of 30, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, thereby forming an insulating reinforcement portion in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water and performing nano-TA measurements on the surface of the area that was in contact with the aluminum alloy foil using an atomic force microscope. The coating is formed by drying it in an oven set to 150°C for 10 minutes to a thickness of 70 nm to 150 nm. The insulating reinforcement part is formed by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water and performing nano-TA measurements on the surface of the area that was in contact with the aluminum alloy foil, and determining that the layer is one in which no peak top is detected in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A.

[0155] 1 Adhesive member for metal terminals 2 Metal terminals 3 Exterior material for energy storage devices 3a Peripheral edge of the exterior material for energy storage devices 4 Energy storage device element 10 Energy storage device 11 Intermediate layer 12a First resin layer 12b Second resin layer 13 Adhesion promoter layer 31 Base layer 32 Adhesive layer 33 Barrier layer 34 Adhesive layer 35 Heat-sealable resin layer 36 Cover 37 Frame

Claims

1. An adhesive member for metal terminals interposed between a metal terminal electrically connected to the electrodes of an energy storage device element and an outer casing for an energy storage device that seals the energy storage device element, wherein the adhesive member for metal terminals includes a resin layer A that constitutes at least one surface of the adhesive member for metal terminals, and when the resin layer A of the adhesive member for metal terminals is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a silicone rubber with a thickness of 2.0 mm and a hardness of 30, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, an insulating reinforcement portion is formed in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by dissolving and removing the aluminum alloy foil with 10% hydrochloric acid, then washing it with water. The solution is prepared in a mass ratio of polyacrylic acid aqueous solution: polyethylene glycol aqueous solution: 28% ammonia water = 1:1:1, and drying it in an oven set to 150°C for 10 minutes to achieve a film thickness of 70 nm to 150 nm. The insulating reinforcement part is formed by dissolving and removing the aluminum alloy foil with 10% hydrochloric acid, then washing it with water and performing nano-TA measurement on the surface of the area that was in contact with the aluminum alloy foil using an atomic force microscope. The layer is one in which no peak top is detected in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A.

2. The adhesive member for metal terminals according to claim 1, wherein the resin layer A contains polyester.

3. The insulating reinforcement portion is a layer in which no peak top is detected in the range above the softening point of the resin layer A and below 250°C in nano-TA measurement using an atomic force microscope, as described in claim 1 or 2, for the adhesive member for metal terminals.

4. The adhesive member for metal terminals according to claim 1 or 2, wherein the adhesive member for metal terminals is composed of a single layer or multiple layers.

5. A metal terminal with an adhesive member for metal terminals, wherein an adhesive member for metal terminals is attached to a metal terminal, the adhesive member for metal terminals includes a resin layer A that constitutes at least one surface of the adhesive member for metal terminals, an insulating reinforcement portion is formed on at least a part of the resin layer A of the adhesive member for metal terminals, and the insulating reinforcement portion is a layer in which no peak top is detected in nano-TA measurement using an atomic force microscope in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A, the metal terminal with an adhesive member for metal terminals.

6. An energy storage device comprising at least a positive electrode, a negative electrode, and an electrolyte; an outer casing for the energy storage device that seals the energy storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, for electrically connecting the outside of the energy storage device to the energy storage device element, wherein an adhesive member for metal terminals is interposed between the metal terminals and the outer casing for the energy storage device, the adhesive member for metal terminals includes a resin layer A that constitutes at least one side surface of the adhesive member for metal terminals, an insulating reinforcement portion is formed on at least a part of the resin layer A of the adhesive member for metal terminals, and the insulating reinforcement portion is a layer in which no peak top is detected in nano-TA measurement from the surface using an atomic force microscope in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A.

7. A method for manufacturing an energy storage device comprising at least a positive electrode, a negative electrode, and an electrolyte; an outer casing for the energy storage device that seals the energy storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, for electrically connecting the outside of the energy storage device to the energy storage device element, the method comprising the step of interposing the adhesive member for metal terminals described in claim 1 or 2 between the metal terminals and the outer casing for the energy storage device, and sealing the energy storage device element with the outer casing for the energy storage device.

8. A method for manufacturing an energy storage device, comprising at least a positive electrode, a negative electrode, and an electrolyte; an outer casing for an energy storage device that seals the energy storage device element; and metal terminals electrically connected to the positive electrode and the negative electrode, respectively, for electrically connecting the outside of the energy storage device to the energy storage device element, the method comprising the step of sealing the energy storage device element with the outer casing for an energy storage device by interposing the metal terminal with the adhesive member for metal terminals described in claim 5.

9. A kit comprising an adhesive member for metal terminals and an outer casing for an energy storage device, wherein the adhesive member for metal terminals includes a resin layer A that constitutes at least one surface of the adhesive member for metal terminals, and the resin layer A of the adhesive member for metal terminals is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a 2.0 mm thick, hardness 30 silicone rubber, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, thereby forming an insulating reinforcement portion in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water. The solution is prepared in a mass ratio of 1:1:1 for the polyacrylic acid aqueous solution, polyethylene glycol aqueous solution, and 28% ammonia water. The coating is then dried in an oven set to 150°C for 10 minutes to achieve a film thickness of 70 nm to 150 nm. The insulation reinforcement section is formed by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water. Nano-TA measurement is performed on the surface of the area that was in contact with the aluminum alloy foil using an atomic force microscope. The layer is one in which no peak top is detected in the temperature range above the softening point of resin layer A and below 15°C above the softening point of resin layer A. A kit used in which, when in use, the adhesive member for metal terminals is interposed between the metal terminals electrically connected to the electrodes of the energy storage device element and the outer casing for the energy storage device that seals the energy storage device element, thereby sealing the energy storage device element with the outer casing for the energy storage device.

10. A method for manufacturing an adhesive member for a metal terminal, which is interposed between a metal terminal electrically connected to the electrodes of an energy storage device element and an outer casing for an energy storage device that seals the energy storage device element, wherein the adhesive member for the metal terminal includes a resin layer A that constitutes at least one surface of the adhesive member for the metal terminal, and the resin layer A of the adhesive member for the metal terminal is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press with a metal head attached to a silicone rubber with a thickness of 2.0 mm and a hardness of 30, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, thereby forming an insulating reinforcement portion in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water, and performing nano-TA measurement on the surface of the area that was in contact with the aluminum alloy foil using an atomic force microscope. The coating is formed by drying it in an oven set to 150°C for 10 minutes to a thickness of 70 nm to 150 nm. The insulating reinforcement part is formed by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water and performing nano-TA measurement on the surface of the area that was in contact with the aluminum alloy foil, and determining that the layer is one in which no peak top is detected in the range of temperature above the softening point of the resin layer A and below 15°C above the softening point of the resin layer A.

11. A method for manufacturing a metal terminal with an adhesive member for metal terminals, comprising the step of attaching an adhesive member for metal terminals to a metal terminal, wherein the adhesive member for metal terminals includes a resin layer A that constitutes at least one surface of the adhesive member for metal terminals, and the resin layer A of the adhesive member for metal terminals is heat-fused to an aluminum alloy foil (thickness 200 μm × TD (width direction) 15 mm × MD (length direction) 100 mm) having a corrosion-resistant coating on its surface using a flat plate press machine with a metal head attached to a silicone rubber with a thickness of 2.0 mm and a hardness of 30, at a temperature of 260°C, a surface pressure of 1 MPa on the silicone rubber, and for 13 seconds, thereby forming an insulating reinforcement portion in at least a part of the resin layer A. The corrosion-resistant coating is formed by applying a chemical treatment solution prepared by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water and performing nano-TA measurements on the surface of the area that was in contact with the aluminum alloy foil using an atomic force microscope. The coating is formed by drying it in an oven set to 150°C for 10 minutes to a thickness of 70 nm to 150 nm. The insulating reinforcement part is formed by dissolving and removing all aluminum alloy foil with 10% hydrochloric acid, then washing it with water and performing nano-TA measurements on the surface of the area that was in contact with the aluminum alloy foil, and determining that the layer is one in which no peak top is detected in the range of temperatures above the softening point of the resin layer A and 15°C higher than the softening point of the resin layer A.

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