WO2021215538A1

WO2021215538A1 - Exterior material for power storage device, method for manufacturing same, and power storage device

Info

Publication number: WO2021215538A1
Application number: PCT/JP2021/016524
Authority: WO
Inventors: 天野　真; 一彦横田; 山下　孝典
Original assignee: 大日本印刷株式会社
Priority date: 2020-04-24
Filing date: 2021-04-23
Publication date: 2021-10-28
Also published as: CN115443577A; JPWO2021215538A1

Abstract

An exterior material for a power storage device is constituted from a laminate provided with at least a substrate layer, a barrier layer, and a heat-fusible resin layer in the sequence listed, the substrate layer being such that the principal axis direction measured by the following measurement method is in the range of 90° ± 30°. [Measurement method] Using a principal-axis-direction measurement device provided with a camera and a light source, when the substrate is positioned between the camera and the light source so that the camera of the measurement device, the substrate layer, and the light source are located on a straight line, and the substrate layer is positioned so that the direction of the TD of the substrate layer is the 0° direction and the direction of the MD of the substrate layer is the 90° direction, the light from the light source is beamed in the thickness direction of the substrate layer and the principal axis direction of the substrate layer is measured.

Description

Exterior materials for power storage devices, their manufacturing methods, and power storage devices

This disclosure relates to an exterior material for a power storage device, a manufacturing method thereof, and a power storage device.

Conventionally, various types of power storage devices have been developed, but in all power storage devices, a packaging material (exterior material) is an indispensable member for sealing the power storage device elements such as electrodes and electrolytes. Conventionally, a metal exterior material has been widely used as an exterior material for a power storage device.

On the other hand, in recent years, with the improvement of high performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., various shapes are required for power storage devices, and thinning and weight reduction are required. However, the metal exterior material for a power storage device, which has been widely used in the past, has a drawback that it is difficult to keep up with the diversification of shapes and there is a limit to weight reduction.

Therefore, conventionally, as an exterior material for a power storage device that can be easily processed into various shapes and can be made thinner and lighter, it is in the form of a film in which a base material / aluminum foil layer / heat-sealing resin layer is sequentially laminated. Exterior materials have been proposed (see, for example, Patent Document 1).

In such a film-like exterior material, a recess is generally formed by cold molding, and a storage device element such as an electrode or an electrolytic solution is arranged in the space formed by the recess to form a heat-sealing resin. By heat-sealing the layers together, a power storage device in which the power storage device element is housed inside the exterior material can be obtained.

Japanese Unexamined Patent Publication No. 2008-287971

In recent years, film-like exterior materials have been required to be further thinned. Further, from the viewpoint of further increasing the energy density of the power storage device, it is also required to form a deeper recess in the exterior material.

However, there is a problem that cracks and pinholes are likely to occur when a film-shaped exterior material for a power storage device is formed to form a recess for accommodating the power storage device element.

The present disclosure provides an exterior material for a power storage device, which is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order, and has excellent moldability. The main purpose is that.

The inventors of the present disclosure have made diligent studies to solve the above problems. As a result, it is an exterior material for a power storage device composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order, and the base material layer is measured by the following measuring method. It has been found that the exterior material for a power storage device having a principal axis orientation within the range of 90 ° ± 30 ° has excellent moldability.
[Measuring method]
Using a spindle orientation measuring device equipped with a camera and a light source, the base material layer is set so that the camera of the measuring device, the base material layer of the exterior material for the power storage device, and the light source of the measuring device are located in a straight line. When the base material layer is arranged between the light source and the light source so that the TD direction of the base material layer is 0 ° and the MD direction of the base material layer is 90 °, the base material layer The light of the light source is irradiated in the thickness direction, and the principal axis orientation of the base material layer is measured.

In order to improve the moldability of the exterior material for power storage devices, the base material layer may be selected based on the tensile breaking strength (MPa) of the film used for the base material layer. However, especially when the thickness of the base material layer becomes thin, the difference in the tensile force (N) of the base material layer becomes small, and there is a clear difference between the tensile breaking strength of the base material layer and the moldability of the exterior material for the power storage device. Correlation is hard to find. On the other hand, as a result of examination by the inventors of the present disclosure, even in such a case, if the principal axis orientation of the base material layer is within the predetermined range, the physical properties of the base material layer and the exterior material for the power storage device are examined. A clear correlation was found with the formability of. Further, the measurement test of the tensile breaking strength is a fracture test, but the measurement test of the principal axis orientation is a non-destructive test, and there is an advantage that the substrate layer can be selected without breaking.

This disclosure has been completed by further studies based on these findings. That is, the present disclosure provides the inventions of the following aspects.
It is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
The base material layer is an exterior material for a power storage device, which is measured by the following measuring method and has a principal axis orientation within the range of 90 ° ± 30 °.
[Measuring method]
A spindle orientation measuring device including a camera and a light source is used so that the camera, the base material layer, and the light source of the measuring device are located in a straight line, and the base material layer is formed between the camera and the light source. When the base material layer is arranged between them so that the TD direction of the base material layer is 0 ° and the MD direction of the base material layer is 90 °, the thickness direction of the base material layer Is irradiated with the light of the light source, and the principal axis direction of the base material layer is measured.

According to the present disclosure, an exterior material for a power storage device, which is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order, and has excellent moldability. Can be provided. Further, according to the present disclosure, it is also possible to provide a method for manufacturing an exterior material for a power storage device and a power storage device.

It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure. It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure. It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure. It is a schematic diagram which shows an example of the cross-sectional structure of the exterior material for a power storage device of this disclosure. It is a schematic diagram for demonstrating the method of accommodating a power storage device element in a package formed by the exterior material for a power storage device of the present disclosure. It is a schematic diagram (perspective view) for demonstrating the measurement method of a spindle direction. It is a schematic view (side view) for demonstrating the measurement method of a spindle direction. It is a schematic diagram (plan view) for demonstrating the measurement method of a spindle direction.

The exterior material for a power storage device of the present disclosure is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order, and the base material layer is measured by the following measuring method. The principal axis orientation is within the range of 90 ° ± 30 °. The exterior material for a power storage device of the present disclosure has excellent moldability by having such a configuration.
[Measuring method]
A spindle orientation measuring device including a camera and a light source is used so that the camera, the base material layer, and the light source of the measuring device are located in a straight line, and the base material layer is formed between the camera and the light source. When the base material layer is arranged between them so that the TD direction of the base material layer is 0 ° and the MD direction of the base material layer is 90 °, the thickness direction of the base material layer Is irradiated with the light of the light source, and the principal axis direction of the base material layer is measured.

Hereinafter, the exterior material for the power storage device of the present disclosure will be described in detail. In this specification, the numerical range indicated by "-" means "greater than or equal to" and "less than or equal to". For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

Regarding the barrier layer 3 described later in the exterior material for a power storage device, it is usually possible to discriminate between MD (Machine Direction) and TD (Transverse Direction) in the manufacturing process thereof. For example, when the barrier layer 3 is made of a metal foil such as an aluminum alloy foil or a stainless steel foil, a line called a so-called rolling mark is formed on the surface of the metal foil in the rolling direction (RD: Rolling Direction) of the metal foil. Shaped streaks are formed. Since the rolling marks extend along the rolling direction, the rolling direction of the metal foil can be grasped by observing the surface of the metal foil. Further, in the manufacturing process of the laminated body, since the MD of the laminated body and the RD of the metal foil usually match, the surface of the metal foil of the laminated body is observed and the rolling direction (RD) of the metal foil is specified. Thereby, the MD of the laminated body can be specified. Further, since the TD of the laminated body is in the direction perpendicular to the MD of the laminated body, the TD of the laminated body can also be specified.

Further, when the MD of the exterior material for the power storage device cannot be specified due to the rolling marks of the metal foil such as the aluminum alloy foil or the stainless steel foil, it can be specified by the following method. As a method of confirming the MD of the exterior material for the electricity storage device, there is a method of observing the cross section of the heat-sealing resin layer of the exterior material for the electricity storage device with an electron microscope to confirm the sea-island structure. In this method, the direction parallel to the cross section in which the average diameter of the island shape in the direction perpendicular to the thickness direction of the heat-sealing resin layer is the maximum can be determined as MD. Specifically, the angle is changed by 10 degrees from the cross section of the heat-sealing resin layer in the length direction and the direction parallel to the cross section in the length direction to the direction perpendicular to the cross section in the length direction. Each cross section (10 cross sections in total) is observed with an electron micrograph to confirm the sea-island structure. Next, in each cross section, the shape of each island is observed. For the shape of each island, the diameter y is the linear distance connecting the leftmost end in the direction perpendicular to the thickness direction of the heat-sealing resin layer and the rightmost end in the vertical direction. In each cross section, the average of the top 20 diameters y is calculated in descending order of the diameter y of the island shape. The direction parallel to the cross section in which the average of the diameter y of the island shape is the largest is determined as MD.

1. 1. Laminated structure of exterior material for power storage device The exterior material 10 for power storage device of the present disclosure is a laminated body including a base material layer 1, a barrier layer 3, and a heat-sealing resin layer 4 in this order, for example, as shown in FIG. It is composed of. In the exterior material 10 for a power storage device, the base material layer 1 is on the outermost layer side, and the heat-sealing resin layer 4 is on the innermost layer. When assembling a power storage device using the power storage device exterior material 10 and the power storage device element, the peripheral portion is heat-sealed with the heat-sealing resin layers 4 of the power storage device exterior material 10 facing each other. The power storage device element is housed in the space formed by. In the laminate constituting the exterior material 10 for the power storage device of the present disclosure, the heat-sealing resin layer 4 side is inside the barrier layer 3 and the base material layer 1 side is more than the barrier layer 3 with the barrier layer 3 as a reference. It is the outside.

As shown in FIGS. 2 to 4, for example, the exterior material 10 for a power storage device is used, if necessary, for the purpose of enhancing the adhesiveness between the base material layer 1 and the barrier layer 3 and the like. It may have an adhesive layer 2. Further, for example, as shown in FIGS. 3 and 4, the adhesive layer 5 is required between the barrier layer 3 and the heat-sealing resin layer 4 for the purpose of enhancing the adhesiveness between the layers. May have. Further, as shown in FIG. 4, a surface coating layer 6 or the like may be provided on the outside of the base material layer 1 (the side opposite to the heat-sealing resin layer 4 side), if necessary.

The thickness of the laminate constituting the exterior material 10 for the power storage device is not particularly limited, but from the viewpoint of cost reduction, energy density improvement, etc., for example, about 190 μm or less, preferably about 180 μm or less, about 155 μm or less, about 120 μm. Hereinafter, it is about 100 μm or less. Further, the thickness of the laminate constituting the exterior material 10 for the power storage device is preferably about 35 μm or more, about 45 μm or more, and about from the viewpoint of maintaining the function of the exterior material for the power storage device of protecting the power storage device element. 60 μm or more can be mentioned. The preferred range of the laminated body constituting the exterior material 10 for the power storage device is, for example, about 35 to 190 μm, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 35 to 100 μm, about 45 to 190 μm. About 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 45 to 100 μm, about 60 to 190 μm, about 60 to 180 μm, about 60 to 155 μm, about 60 to 120 μm, about 60 to 100 μm, in particular 60 It is preferably about 100 μm.

In the power storage device exterior material 10, the base material layer 1, the adhesive layer 2 provided as necessary, the barrier layer 3, and if necessary with respect to the thickness (total thickness) of the laminate constituting the power storage device exterior material 10. The ratio of the total thickness of the adhesive layer 5, the heat-sealing resin layer 4, and the surface coating layer 6 provided as needed is preferably 90% or more, more preferably 95% or more. More preferably, it is 98% or more. As a specific example, when the exterior material 10 for a power storage device of the present disclosure includes a base material layer 1, an adhesive layer 2, a barrier layer 3, an adhesive layer 5, and a heat-sealing resin layer 4, the exterior for a power storage device The ratio of the total thickness of each of these layers to the thickness (total thickness) of the laminate constituting the material 10 is preferably 90% or more, more preferably 95% or more, and further preferably 98% or more. Further, even when the exterior material 10 for a power storage device of the present disclosure is a laminated body including a base material layer 1, an adhesive layer 2, a barrier layer 3, and a heat-sealing resin layer 4, the exterior material for a power storage device is also used. The ratio of the total thickness of each of these layers to the thickness (total thickness) of the laminate constituting 10 is, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and further preferably 98% or more. Can be done.

2. Each layer forming the exterior material for the power storage device [base material layer 1]
In the present disclosure, the base material layer 1 is a layer provided for the purpose of exerting a function as a base material of an exterior material for a power storage device. The base material layer 1 is located on the outer layer side of the exterior material for the power storage device. The base material layer 1 may be the outermost layer (layer constituting the outer surface). For example, when the surface coating layer 6 described later is provided, the surface coating layer 6 is the outermost layer (layer constituting the outer surface). ) May be.

In the present disclosure, the base material layer 1 is characterized in that a predetermined principal axis direction is within the range of 90 ° ± 30 °. That is, as shown in the schematic views of FIGS. 6 to 8, the camera C of the spindle orientation measuring device, the base material layer 1 of the exterior material for the power storage device, and the light source LS of the spindle orientation measuring device are aligned. The base material layer 1 is arranged between the camera C and the light source LS so as to be positioned so that the TD direction of the base material layer 1 is 0 ° and the MD direction of the base material layer 1 is 90 °. When the base material layer 1 is arranged as described above, the principal axis orientation of the base material layer 1 measured by irradiating the light L of the light source LS in the thickness direction (z direction) of the base material layer 1 is 90 ° ± 30. It is within the range of ° (that is, 60 to 120 °). From the viewpoint of more preferably exerting the effects of the invention of the present disclosure, the principal axis orientation of the base material layer 1 is preferably within the range of 90 ° ± 25 ° (that is, 65 to 115 °), more preferably 90 ° ± 20. Within ° (ie, 70-110 °), more preferably within 90 ° ± 15 ° (ie, 75-105 °), even more preferably within 90 ° ± 10 ° (ie, 80-100). °), more preferably in the range of 90 ° ± 5 ° (ie, 85-95 °). The method for measuring the principal axis direction of the base material layer 1 is as follows.

<Measurement of spindle direction>
For each of the base material layers (resin films constituting the base material layer), as shown in the schematic views of FIGS. 6 to 8, a spindle orientation measuring device including a camera C and a light source LS is used, and the camera C of the measuring device is used. The base material layer 1 is arranged between the camera C and the light source LS so that the base material layer 1 and the light source LS are located in a straight line, and the TD direction of the base material layer 1 is set to 0 °. The measurement was performed by irradiating the light L of the light source LS in the thickness direction D of the base material layer 1 with the MD direction of the material layer 1 as the 90 ° direction. As shown in the schematic views of FIGS. 6 and 7, in the measurement, the light L is irradiated from the light source arranged on the back side of the base material layer 1 in the thickness direction (z direction) of the base material layer 1. A transparent glass plate G is arranged on the base material layer 1 (on the camera C side), and the measurement is performed so that wrinkles are not formed on the surface of the base material layer 1. Further, although not shown in FIGS. 6 to 8, the base material layer 1 and the glass plate G are arranged in order on a plate provided with an opening at a position where the base material layer 1 is irradiated with light. The measurement is carried out so that the light L passes through the base material layer 1 and the glass plate G through the opening of the plate. The specific measurement conditions are as follows. When the base material layer (resin film constituting the base material layer) is acquired from the power storage device or the exterior material for the power storage device and the principal axis direction of the base material layer 1 is measured, the heat-sealed portion of the power storage device is used. The exterior material for the power storage device is obtained from the top surface or the bottom surface, not from the side surface or the side surface, and a sample is prepared. In the present disclosure, the main axis orientation of the base material layer is the phase advance axis.
(Measurement condition)
Measuring device: For example, polarized high-speed imaging device (CRYSTA PI-5) manufactured by Photron Co., Ltd.
Analysis software: For example, KAMAKIRI offline basic software Ver: 1.5.0.1
Measurement sample: The base material layer is prepared by cutting it into, for example, A4 size (TD210 mm × MD300 mm).
Measurement wavelength (camera side): 520 to 570 nm (The camera that receives light through the film detects light with a wavelength of 520 to 570 nm)
Light source: White LED light (measurement samples are placed so that the positional relationship between the light source (light), the base material layer, and the camera coincides with the extension line of the light source and the thickness direction of the base material layer, and the camera is placed on the extension line of the light source. Is placed.)

The mechanism by which the moldability of the exterior material 10 for the power storage device is improved by keeping the predetermined principal axis orientation of the base material layer 1 within the range of 90 ° ± 30 ° can be considered as follows. That is, in the molding of the exterior material for a power storage device, it is general that a rectangular molded portion (recess) having a side parallel to the MD direction is formed by cold molding using a mold. Here, in the circumference of the ridgeline portion of the molded portion, the area to be stretched is large in the side portion of the rectangle, and the corner portion (near 45 °) has a small stretched area. The fact that the principal axis orientation of the base material layer is 90 ° ± 30 ° means that the base material layers are considered to have relatively uniform molecular orientations along the MD direction. Therefore, it is considered that when the exterior material for the power storage device is molded, the resistance to the stretching of the ridgeline portion of the rectangular side portion having a large stretched area becomes strong and it becomes difficult for the pinhole to be formed. On the other hand, when the principal axis orientation of the base material layer exceeds 90 ° ± 30 °, it is considered that the base material layers are relatively aligned in the molecular orientation in the diagonal 45 ° direction with respect to the MD direction. For this reason, when molding the exterior material for the power storage device, the resistance is strong only for the stretching of the ridgeline portion of the corner portion where the stretched area is small, so that the ridgeline portion of the rectangular side portion is stretched. It is presumed that the resistance became weak and pinholes were easily formed.

It is also possible to measure the phase difference of the base material layer 1 in the measurement of the principal axis direction of the base material layer 1. From the viewpoint of more preferably exerting the effects of the invention of the present disclosure, the phase difference of the base material layer 1 is preferably about 210 nm or less, more preferably about 200 nm or less, still more preferably about 150 nm or less, still more preferably about 100 nm or less. More preferably, it is about 80 nm or less. The phase difference of the base material layer 1 is, for example, about 30 nm or more, about 50 nm or more, and the like. The preferred ranges of the phase difference of the base material layer 1 are about 30 to 210 nm, about 30 to 200 nm, about 30 to 150 nm, about 30 to 100 nm, about 30 to 80 nm, about 50 to 210 nm, about 50 to 200 nm, and about 50 to. It is about 150 nm, about 50 to 100 nm, and about 50 to 80 nm.

In order to set the principal axis orientation and the phase difference of the base material layer 1 to the above values, for example, the material, thickness, and various physical properties of the base material layer 1 are adjusted, and the base material layer 1 is formed of a resin film. In some cases, the production conditions such as the stretching method of the resin film (for example, the inflation method, the tenter method, etc.), the stretching ratio, the stretching rate, the cooling temperature, and the heat fixing temperature are adjusted. These adjustments may be made based on known techniques. For example, since the principal axis orientation of the base material layer 1 corresponds to the direction in which the crystallinity of the resin is high, when a resin film produced by a predetermined stretching method is cut into a predetermined size and used as the base material layer, the resin is used. It can also be said that it is effective to select a position to be cut from the film and adopt a substrate layer 1 having the same crystal orientation.

The material forming the base material layer 1 is not particularly limited as long as it has a function as a base material, that is, at least has insulating properties and satisfies the above-mentioned principal axis orientation. The base material layer 1 can be formed by using, for example, a resin, and the resin may contain an additive described later.

The base material layer 1 may be, for example, a resin film formed of a resin, or may be formed by applying a resin. The resin film may be an unstretched film or a stretched film. Examples of the stretched film include a uniaxially stretched film and a biaxially stretched film, and a biaxially stretched film is preferable. Examples of the stretching method for forming the biaxially stretched film include a sequential biaxial stretching method, an inflation method, and a simultaneous biaxial stretching method. Examples of the method for applying the resin include a roll coating method, a gravure coating method, and an extrusion coating method.

Examples of the resin forming the base material layer 1 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicon resin, and phenol resin, and modified products of these resins. Further, the resin forming the base material layer 1 may be a copolymer of these resins or a modified product of the copolymer. Further, it may be a mixture of these resins.

Among these, the resin forming the base material layer 1 preferably includes polyester and polyamide, and particularly preferably polyamide.

Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester. Further, examples of the copolymerized polyester include a copolymerized polyester containing ethylene terephthalate as a repeating unit as a main component. Specifically, copolymer polyester (hereinafter abbreviated after polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / terephthalate / (Sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decandicarboxylate) and the like. These polyesters may be used alone or in combination of two or more.

Specific examples of the polyamide include an aliphatic polyamide such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and a copolymer of nylon 6 and nylon 66; terephthalic acid and / or isophthalic acid. Hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamide such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I stands for isophthalic acid, T stands for terephthalic acid), polyamide MXD6 (polymethaki Polyamide containing aromatics such as silylene adipamide); Alicyclic polyamide such as polyamide PACM6 (polybis (4-aminocyclohexyl) methaneadipamide); Further, lactam component and isocyanate component such as 4,4'-diphenylmethane-diisocyanate Examples thereof include a copolymerized polyamide, a polyesteramide copolymer or a polyether esteramide copolymer which is a copolymer of a copolymerized polyamide and polyester or polyalkylene ether glycol; and a polyamide such as these copolymers. These polyamides may be used alone or in combination of two or more.

The base material layer 1 preferably contains at least one of a polyester film, a polyamide film, and a polyolefin film, and preferably contains at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film. It is more preferable to contain at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film, and a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, and a biaxially stretched nylon film. , It is more preferable to contain at least one of the biaxially stretched polypropylene films. From the viewpoint of more preferably exerting the effects of the invention of the present disclosure, it is particularly preferable that the base material layer 1 is made of a biaxially stretched nylon film.

The base material layer 1 may be a single layer or may be composed of two or more layers. When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminated body in which a resin film is laminated with an adhesive or the like, or the resin is co-extruded to form two or more layers. It may be a laminated body of the resin film. Further, the laminated body of the resin film obtained by co-extruding the resin into two or more layers may be used as the base material layer 1 without being stretched, or may be uniaxially stretched or biaxially stretched as the base material layer 1.

Specific examples of the laminate of two or more layers of resin film in the base material layer 1 include a laminate of a polyester film and a nylon film, a laminate of two or more layers of nylon film, and a laminate of two or more layers of polyester film. And the like, preferably, a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more layers of stretched nylon film, and a laminate of two or more layers of stretched polyester film are preferable. For example, when the base material layer 1 is a laminate of two layers of resin film, a laminate of polyester resin film and polyester resin film, a laminate of polyamide resin film and polyamide resin film, or a laminate of polyester resin film and polyamide resin film. A laminate is preferable, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of a nylon film and a nylon film, or a laminate of a polyethylene terephthalate film and a nylon film is more preferable. Further, since the polyester resin is difficult to discolor when the electrolytic solution adheres to the surface, for example, when the base material layer 1 is a laminate of two or more resin films, the polyester resin film is the base material layer 1. It is preferably located in the outermost layer.

When the base material layer 1 is a laminated body of two or more layers of resin films, the two or more layers of resin films may be laminated via an adhesive. When the base material layer 1 is a laminate of two or more resin films, at least one layer may have the above-mentioned principal axis orientation. Preferred adhesives include those similar to the adhesives exemplified in the adhesive layer 2 described later. The method of laminating two or more layers of resin films is not particularly limited, and known methods can be adopted. Examples thereof include a dry laminating method, a sandwich laminating method, an extrusion laminating method, and a thermal laminating method, and a dry laminating method is preferable. The laminating method can be mentioned. When laminating by the dry laminating method, it is preferable to use a polyurethane adhesive as the adhesive. At this time, the thickness of the adhesive is, for example, about 2 to 5 μm. Further, an anchor coat layer may be formed on the resin film and laminated. Examples of the anchor coat layer include the same adhesives as those exemplified in the adhesive layer 2 described later. At this time, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

Further, even if additives such as a lubricant, a flame retardant, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent are present on at least one of the surface and the inside of the base material layer 1. good. Only one type of additive may be used, or two or more types may be mixed and used.

In the present disclosure, from the viewpoint of enhancing the moldability of the exterior material for the power storage device, it is preferable that the lubricant is present on the surface of the base material layer 1. The lubricant is not particularly limited, but an amide-based lubricant is preferable. Specific examples of the amide-based lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, bechenic acid amide, hydroxystearic acid amide and the like. Specific examples of the unsaturated fatty acid amide include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleyl palmitate amide, N-stearyl stearyl amide, N-stearyl oleate amide, N-oleyl stealic acid amide, N-stearyl erucate amide and the like. Further, specific examples of methylolamide include methylolstearic acid amide. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbechenic acid amide, and hexamethylene bisstearate. Examples thereof include acid amide, hexamethylene bisbechenic acid amide, hexamethylene hydroxystearic acid amide, N, N'-distearyl adipate amide, and N, N'-distealyl sebasic acid amide. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucate amide, hexamethylene bisoleic acid amide, N, N'-diorail adipate amide, and N, N'-diorail sebacic acid amide. And so on. Specific examples of the fatty acid ester amide include stearoamide ethyl stearate and the like. Specific examples of the aromatic bisamide include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, and N, N'-distearyl isophthalic acid amide. One type of lubricant may be used alone, or two or more types may be used in combination.

When the lubricant is present on the surface of the base material layer 1, the abundance thereof is not particularly limited, but is preferably about 3 mg / m ² or more, more preferably about 4 to 15 mg / m ² , and further preferably 5 to 14 mg. / M ² is mentioned.

The lubricant existing on the surface of the base material layer 1 may be one in which the lubricant contained in the resin constituting the base material layer 1 is exuded, or one in which the lubricant is applied to the surface of the base material layer 1. You may.

The thickness of the base material layer 1 is not particularly limited as long as it functions as a base material, but is preferably about 10 μm or more, more preferably about 15 μm or more, from the viewpoint of more preferably exerting the effects of the invention of the present disclosure. be. From the same viewpoint, it is preferably about 50 μm or less, more preferably about 40 μm or less, still more preferably about 30 μm or less, still more preferably about 25 μm or less, still more preferably about 20 μm or less. The preferable range of the thickness of the base material layer 1 is about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 10 to 20 μm, about 15 to 50 μm, about 15 to 40 μm, and about 15 to 30 μm. The degree is about 15 to 25 μm and about 15 to 20 μm. When the base material layer 1 is a laminate of two or more resin films, the thickness of the resin films constituting each layer is preferably about 2 to 25 μm, respectively.

[Adhesive layer 2]
In the exterior material for a power storage device of the present disclosure, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary for the purpose of enhancing the adhesiveness between the base material layer 1 and the barrier layer 3.

The adhesive layer 2 is formed by an adhesive capable of adhering the base material layer 1 and the barrier layer 3. The adhesive used for forming the adhesive layer 2 is not limited, but may be any of a chemical reaction type, a solvent volatile type, a heat melting type, a hot pressure type and the like. Further, it may be a two-component curable adhesive (two-component adhesive), a one-component curable adhesive (one-component adhesive), or a resin that does not involve a curing reaction. Further, the adhesive layer 2 may be a single layer or a multilayer.

Specific examples of the adhesive component contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester; polyether; polyurethane; epoxy resin; Phenolic resin; polyamide such as nylon 6, nylon 66, nylon 12, copolymerized polyamide; polyolefin resin such as polyolefin, cyclic polyolefin, acid-modified polyolefin, acid-modified cyclic polyolefin; polyvinyl acetate; cellulose; (meth) acrylic resin; Polyethylene; polycarbonate; amino resin such as urea resin and melamine resin; rubber such as chloroprene rubber, nitrile rubber and styrene-butadiene rubber; silicone resin and the like. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, a polyurethane adhesive is preferable. In addition, the resins used as these adhesive components can be used in combination with an appropriate curing agent to increase the adhesive strength. An appropriate curing agent is selected from polyisocyanate, polyfunctional epoxy resin, oxazoline group-containing polymer, polyamine resin, acid anhydride and the like, depending on the functional group of the adhesive component.

Examples of the polyurethane adhesive include a polyurethane adhesive containing a first agent containing a polyol compound and a second agent containing an isocyanate compound. Preferably, a two-component curable polyurethane adhesive using a polyol such as a polyester polyol, a polyether polyol, and an acrylic polyol as a first agent and an aromatic or aliphatic polyisocyanate as a second agent can be mentioned. Examples of the polyurethane adhesive include a polyurethane adhesive in which a polyol compound and an isocyanate compound are reacted in advance, and a polyurethane adhesive containing the isocyanate compound. Further, examples of the polyurethane adhesive include a polyurethane adhesive in which a polyol compound and an isocyanate compound are reacted in advance, and a polyurethane adhesive containing the polyol compound. Examples of the polyurethane adhesive include a polyurethane adhesive obtained by reacting a polyurethane compound in which a polyol compound and an isocyanate compound are previously reacted with water such as in the air to cure the polyurethane compound. As the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group in the side chain in addition to the hydroxyl group at the end of the repeating unit. Examples of the second agent include aliphatic, alicyclic, aromatic, and aromatic aliphatic isocyanate compounds. Examples of the isocyanate-based compound include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate. (MDI), naphthalenediocyanate (NDI) and the like. Moreover, a polyfunctional isocyanate modified product from one kind or two or more kinds of these diisocyanates and the like can be mentioned. Further, a multimer (for example, a trimer) can be used as the polyisocyanate compound. Examples of such a multimer include an adduct body, a biuret body, a nurate body and the like. Since the adhesive layer 2 is formed of the polyurethane adhesive, excellent electrolytic solution resistance is imparted to the exterior material for the power storage device, and even if the electrolytic solution adheres to the side surface, the base material layer 1 is suppressed from peeling off. ..

Further, the adhesive layer 2 may contain a colorant, a thermoplastic elastomer, a tackifier, a filler, etc., as long as the addition of other components is permitted as long as the adhesiveness is not impaired. Since the adhesive layer 2 contains a colorant, the exterior material for the power storage device can be colored. As the colorant, known ones such as pigments and dyes can be used. Further, only one type of colorant may be used, or two or more types may be mixed and used.

The type of pigment is not particularly limited as long as it does not impair the adhesiveness of the adhesive layer 2. Examples of organic pigments include azo-based, phthalocyanine-based, quinacridone-based, anthracinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindrenine-based, and benzimidazolone-based pigments, which are inorganic. Examples of the pigment include carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments, and other examples include fine powder of mica (mica) and fish scale foil.

Among the colorants, carbon black is preferable in order to make the appearance of the exterior material for the power storage device black, for example.

The average particle size of the pigment is not particularly limited, and examples thereof include about 0.05 to 5 μm, preferably about 0.08 to 2 μm. The average particle size of the pigment is the median size measured by the laser diffraction / scattering type particle size distribution measuring device.

The content of the pigment in the adhesive layer 2 is not particularly limited as long as the exterior material for the power storage device is colored, and examples thereof include about 5 to 60% by mass, preferably 10 to 40% by mass.

The thickness of the adhesive layer 2 is not particularly limited as long as the base material layer 1 and the barrier layer 3 can be adhered to each other, but is, for example, about 1 μm or more and about 2 μm or more. The thickness of the adhesive layer 2 is, for example, about 10 μm or less and about 5 μm or less. The preferable range of the thickness of the adhesive layer 2 is about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[Colored layer]
The colored layer is a layer provided between the base material layer 1 and the barrier layer 3 as needed (not shown). When the adhesive layer 2 is provided, a colored layer may be provided between the base material layer 1 and the adhesive layer 2 and between the adhesive layer 2 and the barrier layer 3. Further, a colored layer may be provided on the outside of the base material layer 1. By providing the colored layer, the exterior material for the power storage device can be colored.

The colored layer can be formed, for example, by applying an ink containing a colorant to the surface of the base material layer 1 or the surface of the barrier layer 3. As the colorant, known ones such as pigments and dyes can be used. Further, only one type of colorant may be used, or two or more types may be mixed and used.

Specific examples of the colorant contained in the colored layer include the same as those exemplified in the column of [Adhesive layer 2].

[Barrier layer 3]
In the exterior material for a power storage device, the barrier layer 3 is at least a layer that suppresses the infiltration of water.

Examples of the barrier layer 3 include a metal foil having a barrier property, a thin-film deposition film, a resin layer, and the like. Examples of the vapor deposition film include a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, and the like, and examples of the resin layer include polymers and tetras mainly composed of polyvinylidene chloride and chlorotrifluoroethylene (CTFE). Examples thereof include polymers containing fluoroethylene (TFE) as a main component, polymers having a fluoroalkyl group, fluorine-containing resins such as polymers containing fluoroalkyl units as a main component, and ethylene vinyl alcohol copolymers. Further, examples of the barrier layer 3 include a resin film provided with at least one of these vapor-deposited films and a resin layer. A plurality of barrier layers 3 may be provided. The barrier layer 3 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 3 include an aluminum alloy, stainless steel, titanium steel, and a steel plate. When used as a metal foil, the metal material includes at least one of an aluminum alloy foil and a stainless steel foil. Is preferable.

From the viewpoint of improving the moldability of the exterior material for the power storage device, the aluminum alloy foil is more preferably a soft aluminum alloy foil composed of, for example, an annealed aluminum alloy, and from the viewpoint of further improving the moldability. Therefore, it is preferable that the aluminum alloy foil contains iron. In the aluminum alloy foil containing iron (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. When the iron content is 0.1% by mass or more, an exterior material for a power storage device having more excellent moldability can be obtained. When the iron content is 9.0% by mass or less, a more flexible exterior material for a power storage device can be obtained. Examples of the soft aluminum alloy foil include aluminum alloys having a composition specified by JIS H4160: 1994 A8021HO, JIS H4160: 1994 A8079HO, JIS H4000: 2014 A8021PO, or JIS H4000: 2014 A8077P-O. Foil is mentioned. Further, if necessary, silicon, magnesium, copper, manganese and the like may be added. Further, softening can be performed by annealing or the like.

Examples of stainless steel foils include austenite-based, ferrite-based, austenite-ferritic-based, martensitic-based, and precipitation-hardened stainless steel foils. Further, from the viewpoint of providing an exterior material for a power storage device having excellent moldability, the stainless steel foil is preferably made of austenitic stainless steel.

Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among these, SUS304 is particularly preferable.

In the case of a metal foil, the thickness of the barrier layer 3 may at least exhibit a function as a barrier layer that suppresses the infiltration of water, and is, for example, about 9 to 200 μm. The thickness of the barrier layer 3 is preferably about 85 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, and particularly preferably about 35 μm or less. The thickness of the barrier layer 3 is preferably about 10 μm or more, more preferably about 20 μm or more, and more preferably about 25 μm or more. The preferred range of the thickness of the barrier layer 3 is about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, and about 20 to. Examples thereof include about 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 3 is made of an aluminum alloy foil, the above range is particularly preferable. Further, in particular, when the barrier layer 3 is made of stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, still more preferably about 30 μm. Below, it is particularly preferably about 25 μm or less. The thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. The preferred range of the thickness of the stainless steel foil is about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, and about 15 to. Examples thereof include about 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

When the barrier layer 3 is a metal foil, it is preferable that a corrosion-resistant film is provided on at least the surface opposite to the base material layer in order to prevent dissolution and corrosion. The barrier layer 3 may be provided with a corrosion resistant film on both sides. Here, the corrosion-resistant film is, for example, a hot water transformation treatment such as boehmite treatment, a chemical conversion treatment, an anodization treatment, a plating treatment such as nickel or chromium, and a corrosion prevention treatment for applying a coating agent on the surface of the barrier layer. Refers to a thin film that makes the barrier layer provided with corrosion resistance (for example, acid resistance, alkali resistance, etc.). Specifically, the corrosion-resistant film means a film for improving the acid resistance of the barrier layer (acid-resistant film), a film for improving the alkali resistance of the barrier layer (alkali-resistant film), and the like. As the treatment for forming the corrosion-resistant film, one type may be performed, or two or more types may be combined. Moreover, not only one layer but also multiple layers can be used. Further, among these treatments, the hydrothermal modification treatment and the anodizing treatment are treatments in which the surface of the metal foil is dissolved by the treatment agent to form a metal compound having excellent corrosion resistance. In addition, these processes may be included in the definition of chemical conversion process. When the barrier layer 3 has a corrosion-resistant film, the barrier layer 3 includes the corrosion-resistant film.

The corrosion-resistant film is formed by preventing delamination between the barrier layer (for example, aluminum alloy foil) and the base material layer during molding of the exterior material for a power storage device, and by hydrogen fluoride generated by the reaction between the electrolyte and water. , Melting and corrosion of the surface of the barrier layer, especially when the barrier layer is an aluminum alloy foil, it prevents the aluminum oxide existing on the surface of the barrier layer from melting and corroding, and the adhesiveness (wetness) of the surface of the barrier layer. The effect of preventing the corrosion between the base material layer and the barrier layer at the time of heat sealing and the prevention of the corrosion between the base material layer and the barrier layer at the time of molding is shown.

Various corrosion-resistant films formed by chemical conversion treatment are known, and mainly, at least one of phosphate, chromate, fluoride, triazinethiol compound, and rare earth oxide. Examples thereof include a corrosion-resistant film containing. Examples of the chemical conversion treatment using phosphate and chromate include chromic acid chromate treatment, chromic acid chromate treatment, phosphoric acid-chromate treatment, and chromate treatment, and chromium used in these treatments. Examples of the compound include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium bicarbonate, acetylacetate chromate, chromium chloride, chromium sulfate and the like. In addition, examples of the phosphorus compound used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid and the like. Further, examples of the chromate treatment include etching chromate treatment, electrolytic chromate treatment, and coating type chromate treatment, and coating type chromate treatment is preferable. In this coating type chromate treatment, at least the inner layer side surface of the barrier layer (for example, aluminum alloy foil) is first known as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activation method and the like. Degreasing is performed by the treatment method, and then metal phosphates such as Cr phosphate (chromium) salt, Ti (titanium) phosphate, Zr (zyroxide) salt, and Zn (zinc) phosphate are applied to the degreased surface. A treatment liquid containing a salt and a mixture of these non-metal salts as a main component, or a treatment liquid containing a mixture of a phosphate non-metal salt and these non-metal salts as a main component, or a synthetic resin and the like. This is a treatment in which a treatment liquid composed of a mixture is coated by a well-known coating method such as a roll coating method, a gravure printing method, or a dipping method, and dried. As the treatment liquid, for example, various solvents such as water, alcohol-based solvent, hydrocarbon-based solvent, ketone-based solvent, ester-based solvent, and ether-based solvent can be used, and water is preferable. Examples of the resin component used at this time include polymers such as phenol-based resins and acrylic-based resins, and aminoated phenol polymers having repeating units represented by the following general formulas (1) to (4) can be used. Examples thereof include the chromate treatment used. In the amination phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more. May be good. The acrylic resin shall be a polyacrylic acid, an acrylic acid methacrylate copolymer, an acrylic acid maleic acid copolymer, an acrylic acid styrene copolymer, or a derivative of these sodium salts, ammonium salts, amine salts, etc. Is preferable. In particular, derivatives of polyacrylic acid such as ammonium salt, sodium salt, and amine salt of polyacrylic acid are preferable. In the present disclosure, polyacrylic acid means a polymer of acrylic acid. Further, the acrylic resin is preferably a copolymer of an acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride, and an ammonium salt or a sodium salt of a copolymer of an acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride. Alternatively, it is preferably an amine salt. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. Further, R ¹ and R ² represent a hydroxy group, an alkyl group, or a hydroxyalkyl group, respectively, which are the same or different. In the general formulas (1) to (4) ^{, examples of the alkyl group represented by X, R 1} and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group. Examples thereof include a linear or branched alkyl group having 1 to 4 carbon atoms such as a tert-butyl group. Examples of the hydroxyalkyl groups represented by X, R ¹ and R ² include a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group and 3-. A linear or branched chain having 1 to 4 carbon atoms in which one hydroxy group such as a hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, or a 4-hydroxybutyl group is substituted. Alkyl groups can be mentioned. In the general formulas (1) to (4), the ^{alkyl group and the hydroxyalkyl group represented by X, R 1} and R ² may be the same or different, respectively. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group or a hydroxyalkyl group. The number average molecular weight of the amination phenol polymer having the repeating unit represented by the general formulas (1) to (4) is, for example, preferably about 5 to 1,000,000, and preferably about 1,000 to 20,000. More preferred. The amination phenol polymer is produced, for example, by polycondensing a phenol compound or a naphthol compound with formaldehyde to produce a polymer composed of repeating units represented by the above general formula (1) or general formula (3), and then forming a formaldehyde. It is produced by introducing a functional group (-CH ₂ NR ¹ R ² ) into the polymer obtained above using an amine (R ¹ R ^{2 NH).} The amination phenol polymer is used alone or in combination of two or more.

As another example of the corrosion resistant film, it is formed by a coating type corrosion prevention treatment in which a coating agent containing at least one selected from the group consisting of a rare earth element oxide sol, an anionic polymer, and a cationic polymer is applied. The thin film to be used is mentioned. The coating agent may further contain phosphoric acid or phosphate, a cross-linking agent for cross-linking the polymer. In the rare earth element oxide sol, fine particles of the rare earth element oxide (for example, particles having an average particle size of 100 nm or less) are dispersed in a liquid dispersion medium. Examples of the rare earth element oxide include cerium oxide, yttrium oxide, neodium oxide, lanthanum oxide and the like, and cerium oxide is preferable from the viewpoint of further improving adhesion. The rare earth element oxide contained in the corrosion-resistant film may be used alone or in combination of two or more. As the liquid dispersion medium of the rare earth element oxide sol, for example, various solvents such as water, alcohol-based solvent, hydrocarbon-based solvent, ketone-based solvent, ester-based solvent, and ether-based solvent can be used, and water is preferable. Examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of polyethyleneimine and a polymer having a carboxylic acid, a primary amine graft acrylic resin obtained by graft-polymerizing a primary amine on an acrylic main skeleton, polyallylamine or a derivative thereof. , Amination phenol and the like are preferable. The anionic polymer is preferably a poly (meth) acrylic acid or a salt thereof, or a copolymer containing (meth) acrylic acid or a salt thereof as a main component. Further, it is preferable that the cross-linking agent is at least one selected from the group consisting of a compound having a functional group of any of an isocyanate group, a glycidyl group, a carboxyl group and an oxazoline group and a silane coupling agent. Further, it is preferable that the phosphoric acid or phosphate is condensed phosphoric acid or condensed phosphate.

As an example of the corrosion-resistant film, a film in which fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide and barium sulfate are dispersed in phosphoric acid is applied to the surface of the barrier layer, and 150 Examples thereof include those formed by performing a baking treatment at a temperature of ° C. or higher.

The corrosion-resistant film may have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated, if necessary. Examples of the cationic polymer and the anionic polymer include those described above.

The composition of the corrosion-resistant film can be analyzed by using, for example, a time-of-flight secondary ion mass spectrometry method.

The amount of the corrosion-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited, but for example, in the case of performing the coating type chromate treatment, the chromic acid compound per ^{1 m 2 of the surface of the barrier layer 3} Is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of chromium, and the phosphorus compound is, for example, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of phosphorus, and an amination phenol polymer. Is preferably contained in a proportion of, for example, about 1.0 to 200 mg, preferably about 5.0 to 150 mg.

The thickness of the corrosion-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably 1 nm to 100 nm, from the viewpoint of the cohesive force of the film and the adhesion to the barrier layer and the heat-sealing resin layer. The degree, more preferably about 1 nm to 50 nm. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope or a combination of observation with a transmission electron microscope and energy dispersion type X-ray spectroscopy or electron beam energy loss spectroscopy. The time-of-flight secondary ion mass spectrometry analysis of the composition of the corrosion resistant coating using, for example, secondary ion consisting Ce and P and O _{_{^{(e.g., Ce 2 PO 4 +, CePO}}} 4 - at least 1, such as species) or, for example, secondary ion of Cr and P and O (e.g., CrPO ₂ ^+, CrPO ₄ ^- peak derived from at least one), such as is detected.

In the chemical conversion treatment, a solution containing a compound used for forming a corrosion-resistant film is applied to the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then the temperature of the barrier layer is applied. It is carried out by heating so that the temperature is about 70 to 200 ° C. Further, before the barrier layer is subjected to the chemical conversion treatment, the barrier layer may be subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method or the like in advance. By performing the degreasing treatment in this way, it becomes possible to more efficiently perform the chemical conversion treatment on the surface of the barrier layer. Further, by using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid for the degreasing treatment, it is possible to form not only the degreasing effect of the metal foil but also the immobile metal fluoride. In such cases, only degreasing treatment may be performed.

[Heat-sealing resin layer 4]
In the exterior material for a power storage device of the present disclosure, the heat-sealing resin layer 4 corresponds to the innermost layer, and has a function of heat-sealing the heat-sealing resin layers with each other when assembling the power storage device to seal the power storage device element. It is a layer (sealant layer) that exerts.

The resin constituting the heat-fusing resin layer 4 is not particularly limited as long as it can be heat-fused, but a resin containing a polyolefin skeleton such as polyolefin or acid-modified polyolefin is preferable. The fact that the resin constituting the heat-sealing resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like. Further, when the resin constituting the heat-sealing resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when measuring the infrared spectroscopy at a maleic anhydride-modified polyolefin, a peak derived from maleic acid is detected in the vicinity of the wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1. When the heat-sealing resin layer 4 is a layer composed of maleic anhydride-modified polyolefin, a peak derived from maleic anhydride is detected when measured by infrared spectroscopy. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; homopolypropylene and block copolymers of polypropylene (for example, with propylene). Polyethylene (for example, a random copolymer of propylene and ethylene) such as a block copolymer of polyethylene), a random copolymer of polyethylene (for example, a random copolymer of propylene and ethylene); a propylene-α-olefin copolymer; a tarpolymer of ethylene-butene-propylene and the like can be mentioned. Among these, polypropylene is preferable. When it is a copolymer, the polyolefin resin may be a block copolymer or a random copolymer. One type of these polyolefin resins may be used alone, or two or more types may be used in combination.

Further, the polyolefin may be a cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Be done. Examples of the cyclic monomer which is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; cyclic diene such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these, cyclic alkene is preferable, and norbornene is more preferable.

Acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of polyolefin with an acid component. As the acid-modified polyolefin, the above-mentioned polyolefin, a copolymer obtained by copolymerizing the above-mentioned polyolefin with a polar molecule such as acrylic acid or methacrylic acid, or a polymer such as a crosslinked polyolefin can also be used. Examples of the acid component used for acid modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride, or anhydrides thereof.

The acid-modified polyolefin may be an acid-modified cyclic polyolefin. The acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin in place of the acid component, or by block-polymerizing or graft-polymerizing the acid component with the cyclic polyolefin. be. The same applies to the cyclic polyolefin that is acid-modified. The acid component used for acid denaturation is the same as the acid component used for denaturation of the polyolefin.

Preferred acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylene modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefin, and maleic anhydride-modified polypropylene.

The heat-sealing resin layer 4 may be formed of one type of resin alone, or may be formed of a blended polymer in which two or more types of resins are combined. Further, the heat-sealing resin layer 4 may be formed of only one layer, but may be formed of two or more layers with the same or different resins.

Further, the heat-sealing resin layer 4 may contain a lubricant or the like, if necessary. When the heat-sealing resin layer 4 contains a lubricant, the moldability of the exterior material for a power storage device can be improved. The lubricant is not particularly limited, and a known lubricant can be used. The lubricant may be used alone or in combination of two or more.

The lubricant is not particularly limited, but an amide-based lubricant is preferable. Specific examples of the lubricant include those exemplified in the base material layer 1. One type of lubricant may be used alone, or two or more types may be used in combination.

When the lubricant is present on the surface of the heat-sealing resin layer 4, the amount of the lubricant is not particularly limited, but is preferably about ^{10 to 50 mg / m 2 from the viewpoint of improving the moldability of the exterior material for the power storage device.} , More preferably about 15 to 40 mg / m ^2.

The lubricant existing on the surface of the heat-sealing resin layer 4 may be one in which the lubricant contained in the resin constituting the heat-sealing resin layer 4 is exuded, or the lubricant contained in the heat-sealing resin layer 4 may be exuded. The surface may be coated with a lubricant.

The thickness of the heat-sealing resin layer 4 is not particularly limited as long as the heat-sealing resin layers have a function of heat-sealing to seal the power storage device element, but is preferably about 100 μm or less, preferably about 100 μm or less. It is about 85 μm or less, more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described later is 10 μm or more, the thickness of the heat-sealing resin layer 4 is preferably about 85 μm or less, more preferably about 15 to 45 μm, for example. When the thickness of the adhesive layer 5 described later is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-sealing resin layer 4 is preferably about 20 μm or more, more preferably 35 to 85 μm. The degree can be mentioned.

[Adhesive layer 5]
In the exterior material for a power storage device of the present disclosure, the adhesive layer 5 is provided between the barrier layer 3 (or the corrosion-resistant film) and the heat-sealing resin layer 4 as necessary in order to firmly bond them. It is a layer to be corroded.

The adhesive layer 5 is formed of a resin capable of adhering the barrier layer 3 and the heat-sealing resin layer 4. As the resin used for forming the adhesive layer 5, for example, the same resin as the adhesive exemplified in the adhesive layer 2 can be used. Further, from the viewpoint of firmly adhering the adhesive layer 5 and the heat-sealing resin layer 4, it is preferable that the resin used for forming the adhesive layer 5 contains a polyolefin skeleton, and the above-mentioned heat-sealing property Examples thereof include the polyolefin exemplified in the resin layer 4 and the acid-modified polyolefin. On the other hand, from the viewpoint of firmly adhering the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 preferably contains an acid-modified polyolefin. Examples of the acid-modifying component include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid, and adipic acid, and anhydrides thereof, acrylic acid, and methacrylic acid. Maleic acid is most preferred. From the viewpoint of heat resistance of the exterior material for the power storage device, the olefin component is preferably polypropylene-based resin, and the adhesive layer 5 most preferably contains maleic anhydride-modified polypropylene.

The fact that the resin constituting the adhesive layer 5 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. Further, the resin constituting the adhesive layer 5 comprises an acid-modified polyolefin, for example, when measuring the infrared spectroscopy at maleic anhydride-modified polyolefin, anhydride in the vicinity of a wave number of 1760 cm ^-1 and near the wave number 1780 cm ^-1 A peak derived from maleic anhydride is detected. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Further, from the viewpoint of ensuring durability such as heat resistance and content resistance of the exterior material for a power storage device and ensuring moldability while reducing the thickness, the adhesive layer 5 is a resin composition containing an acid-modified polyolefin and a curing agent. It is more preferably a cured product. As the acid-modified polyolefin, the above-mentioned ones are preferably exemplified.

The adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. It is particularly preferable that the resin composition is a cured product containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. Further, the adhesive layer 5 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. As the polyester, for example, an ester resin produced by a reaction of an epoxy group and a maleic anhydride group, and an amide ester resin produced by a reaction of an oxazoline group and a maleic anhydride group are preferable. When an unreacted substance of a curing agent such as a compound having an isocyanate group, a compound having an oxazoline group, or an epoxy resin remains in the adhesive layer 5, the presence of the unreacted substance is determined by, for example, infrared spectroscopy. It can be confirmed by a method selected from Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

Further, from the viewpoint of further enhancing the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is selected from at least a group consisting of an oxygen atom, a heterocycle, a C = N bond, and a COC bond. It is preferably a cured product of a resin composition containing a curing agent having one type. Examples of the curing agent having a heterocycle include a curing agent having an oxazoline group and a curing agent having an epoxy group. Examples of the curing agent having a C = N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a C—C bond include a curing agent having an oxazoline group and a curing agent having an epoxy group. The fact that the adhesive layer 5 is a cured product of a resin composition containing these curing agents is, for example, gas chromatograph mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF). -SIMS), X-ray photoelectron spectroscopy (XPS) and other methods can be used for confirmation.

The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively enhancing the adhesion between the barrier layer 3 and the adhesive layer 5, a polyfunctional isocyanate compound is preferable. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include pentandiisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI), which are polymerized or nurate. Examples thereof include chemical compounds, mixtures thereof, and copolymers with other polymers. In addition, an adduct body, a burette body, an isocyanurate body and the like can be mentioned.

The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. More preferably in the range. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. Examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

The proportion of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. It is more preferable to be in. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

Examples of the compound having an epoxy group include an epoxy resin. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by an epoxy group existing in the molecule, and a known epoxy resin can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, and even more preferably about 200 to 800. In the first disclosure, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) measured under the condition that polystyrene is used as a standard sample.

Specific examples of the epoxy resin include glycidyl ether derivative of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, bisphenol F type glycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether and the like. Can be mentioned. One type of epoxy resin may be used alone, or two or more types may be used in combination.

The proportion of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Is more preferable. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

The polyurethane is not particularly limited, and known polyurethane can be used. The adhesive layer 5 may be, for example, a cured product of a two-component curable polyurethane.

The proportion of polyurethane in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. More preferred. As a result, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced in an atmosphere in which a component that induces corrosion of the barrier layer such as an electrolytic solution is present.

When the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin. , The acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

The adhesive layer 5 may contain a modifier having a carbodiimide group.

The thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, and about 5 μm or less. The thickness of the adhesive layer 5 is preferably about 0.1 μm or more and about 0.5 μm or more. The thickness range of the adhesive layer 5 is preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, and about 0.1 to 5 μm. , About 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, and about 0.5 to 5 μm. More specifically, in the case of the adhesive exemplified in the adhesive layer 2 or the cured product of the acid-modified polyolefin and the curing agent, the thickness is preferably about 1 to 10 μm, more preferably about 1 to 5 μm. Further, when the resin exemplified in the heat-sealing resin layer 4 is used, it is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. When the adhesive layer 5 is a cured product of the adhesive exemplified in the adhesive layer 2 or a resin composition containing an acid-modified polyolefin and a curing agent, for example, the resin composition is applied and cured by heating or the like. Thereby, the adhesive layer 5 can be formed. Further, when the resin exemplified in the heat-sealing resin layer 4 is used, it can be formed by, for example, extrusion molding of the heat-sealing resin layer 4 and the adhesive layer 5.

[Surface coating layer 6]
The exterior material for a power storage device of the present disclosure is above the base material layer 1 (base material layer 1), if necessary, for the purpose of improving at least one of designability, electrolytic solution resistance, scratch resistance, moldability, and the like. The surface coating layer 6 may be provided on the side opposite to the barrier layer 3 of the above. The surface coating layer 6 is a layer located on the outermost layer side of the exterior material for the power storage device when the power storage device is assembled using the exterior material for the power storage device.

The surface coating layer 6 can be formed of, for example, a resin such as polyvinylidene chloride, polyester, polyurethane, acrylic resin, or epoxy resin.

When the resin forming the surface coating layer 6 is a curable resin, the resin may be either a one-component curable type or a two-component curable type, but is preferably a two-component curable type. Examples of the two-component curable resin include two-component curable polyurethane, two-component curable polyester, and two-component curable epoxy resin. Of these, two-component curable polyurethane is preferable.

Examples of the two-component curable polyurethane include a polyurethane containing a first agent containing a polyol compound and a second agent containing an isocyanate compound. Preferably, a two-component curable polyurethane using a polyol such as a polyester polyol, a polyether polyol, and an acrylic polyol as a first agent and an aromatic or aliphatic polyisocyanate as a second agent can be mentioned. Examples of the polyurethane include a polyurethane compound obtained by reacting a polyol compound and an isocyanate compound in advance, and a polyurethane containing the isocyanate compound. Examples of the polyurethane include a polyurethane compound obtained by reacting a polyol compound and an isocyanate compound in advance, and a polyurethane containing the polyol compound. Examples of the polyurethane include polyurethane obtained by reacting a polyurethane compound in which a polyol compound and an isocyanate compound are previously reacted with water such as in the air to cure the polyurethane. As the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group in the side chain in addition to the hydroxyl group at the end of the repeating unit. Examples of the second agent include aliphatic, alicyclic, aromatic, and aromatic aliphatic isocyanate compounds. Examples of the isocyanate-based compound include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), and diphenylmethane diisocyanate. (MDI), naphthalenediocyanate (NDI) and the like. Moreover, a polyfunctional isocyanate modified product from one kind or two or more kinds of these diisocyanates and the like can be mentioned. Further, a multimer (for example, a trimer) can be used as the polyisocyanate compound. Examples of such a multimer include an adduct body, a biuret body, a nurate body and the like. The aliphatic isocyanate-based compound refers to an isocyanate having an aliphatic group and no aromatic ring, and the alicyclic isocyanate-based compound refers to an isocyanate having an alicyclic hydrocarbon group, which is an aromatic isocyanate-based compound. Refers to an isocyanate having an aromatic ring. Since the surface coating layer 6 is made of polyurethane, excellent electrolytic solution resistance is imparted to the exterior material for the power storage device.

The surface coating layer 6 has the above-mentioned lubricant or antistatic agent on at least one of the surface and the inside of the surface coating layer 6, depending on the functionality and the like to be provided on the surface coating layer 6 and the surface thereof. It may contain additives such as a blocking agent, a matting agent, a flame retardant, an antioxidant, a tackifier, and an antistatic agent. Examples of the additive include fine particles having an average particle size of about 0.5 nm to 5 μm. The average particle size of the additive shall be the median size measured by the laser diffraction / scattering type particle size distribution measuring device.

The additive may be either an inorganic substance or an organic substance. The shape of the additive is also not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a scaly shape.

Specific examples of additives include talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodium oxide, and antimony oxide. , Titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, refractory nylon, acrylate resin, Examples thereof include crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper and nickel. The additive may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. Further, the additive may be subjected to various surface treatments such as an insulation treatment and a highly dispersible treatment on the surface.

The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method of applying a resin for forming the surface coating layer 6. When an additive is blended in the surface coating layer 6, a resin mixed with the additive may be applied.

The thickness of the surface coating layer 6 is not particularly limited as long as it exhibits the above-mentioned functions as the surface coating layer 6, and examples thereof include about 0.5 to 10 μm, preferably about 1 to 5 μm.

3. 3. Method for Manufacturing Exterior Material for Power Storage Device The method for manufacturing the exterior material for power storage device is not particularly limited as long as a laminated body in which each layer of the exterior material for power storage device of the present invention is laminated can be obtained, and at least the base material. Examples thereof include a method including a step of laminating the layer 1, the barrier layer 3, and the heat-sealing resin layer 4 in this order. That is, the method for manufacturing the exterior material 10 for a power storage device of the present disclosure is a step of laminating at least the base material layer 1, the barrier layer 3, and the heat-sealing resin layer 4 in this order to obtain a laminated body. A main axis orientation measuring device including a camera and a light source is used, and the base material layer is formed between the camera and the light source so that the direction of the camera of the measuring device and the direction of the MD of the base material layer 1 coincide with each other. The principal axis orientation of the base material layer 1 measured by irradiating the light of the light source in the thickness direction of the base material layer is within the range of 90 ° ± 30 °.

An example of the method for manufacturing the exterior material for a power storage device of the present invention is as follows. First, a laminate in which the base material layer 1, the adhesive layer 2, and the barrier layer 3 are laminated in this order (hereinafter, may be referred to as “laminate A”) is formed. Specifically, the laminated body A is formed by applying an adhesive used for forming the adhesive layer 2 on the base material layer 1 or, if necessary, on the barrier layer 3 whose surface has been chemically converted, by a gravure coating method. It can be carried out by a dry laminating method in which the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after being applied and dried by a coating method such as a roll coating method.

Next, the heat-sealing resin layer 4 is laminated on the barrier layer 3 of the laminated body A. When the heat-sealing resin layer 4 is directly laminated on the barrier layer 3, the heat-sealing resin layer 4 is laminated on the barrier layer 3 of the laminated body A by a method such as a thermal laminating method or an extrusion laminating method. do it. When the adhesive layer 5 is provided between the barrier layer 3 and the heat-sealing resin layer 4, for example, (1) the adhesive layer 5 and the heat-sealing resin layer are placed on the barrier layer 3 of the laminated body A. A method of laminating 4 by extruding (coextrusion laminating method, tandem laminating method), (2) Separately, a laminated body in which the adhesive layer 5 and the heat-sealing resin layer 4 are laminated is formed, and the laminated body A is formed. A method of laminating on the barrier layer 3 of the above by a thermal laminating method, or a laminating body in which an adhesive layer 5 is laminated on the barrier layer 3 of the laminated body A is formed, and this is formed by a heat-sealing resin layer 4 and a thermal laminating method. Method of Laminating, (3) While pouring the melted adhesive layer 5 between the barrier layer 3 of the laminated body A and the heat-sealing resin layer 4 which has been formed into a sheet in advance, the adhesive layer 5 is passed through. A method of laminating the laminated body A and the heat-sealing resin layer 4 (sandwich laminating method), (4) a solution coating of an adhesive for forming the adhesive layer 5 on the barrier layer 3 of the laminated body A is performed. Examples thereof include a method of laminating by a method of drying, a method of baking, and the like, and a method of laminating a heat-sealing resin layer 4 which has been formed into a sheet in advance on the adhesive layer 5.

When the surface coating layer 6 is provided, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above resin that forms the surface coating layer 6 to the surface of the base material layer 1. The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer 6.

As described above, the surface coating layer 6 provided as needed / the base material layer 1 / the adhesive layer 2 provided as needed / the barrier layer 3 / the adhesive layer 5 provided as needed / heat fusion A laminate having the sex resin layers 4 in this order is formed, and may be further subjected to heat treatment in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as needed.

In the exterior material for a power storage device, each layer constituting the laminated body may be subjected to surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment, etc., if necessary, to improve processing suitability. .. For example, by applying a corona treatment to the surface of the base material layer 1 opposite to the barrier layer 3, the printability of the ink on the surface of the base material layer 1 can be improved.

4. Applications of exterior materials for power storage devices The exterior materials for power storage devices of the present disclosure are used for packaging for sealing and accommodating power storage device elements such as positive electrodes, negative electrodes, and electrolytes. That is, a power storage device element having at least a positive electrode, a negative electrode, and an electrolyte can be housed in a package formed of the exterior material for a power storage device of the present disclosure to form a power storage device.

Specifically, a power storage device element having at least a positive electrode, a negative electrode, and an electrolyte is provided with the exterior material for the power storage device of the present disclosure in a state in which metal terminals connected to each of the positive electrode and the negative electrode are projected outward. , The peripheral edge of the power storage device element is covered so that a flange portion (a region where the heat-sealing resin layers come into contact with each other) can be formed, and the heat-sealing resin layers of the flange portion are heat-sealed and sealed. Provides a power storage device using an exterior material for the power storage device. When the power storage device element is housed in the package formed of the exterior material for the power storage device of the present disclosure, the heat-sealing resin portion of the exterior material for the power storage device of the present disclosure is inside (the surface in contact with the power storage device element). ) To form a package. The heat-sealing resin layers of the two exterior materials for power storage devices may be overlapped with each other facing each other, and the peripheral edges of the overlapped exterior materials for power storage devices may be heat-sealed to form a package. As in the example shown in FIG. 5, one exterior material for a power storage device may be folded back and overlapped, and the peripheral edge portion may be heat-sealed to form a package. In the case of folding and overlapping, as shown in the example shown in FIG. 5, the side other than the folded side may be heat-sealed to form a package by a three-way seal, or the package may be folded so that a flange portion can be formed. It may be sealed on all sides. Further, in the exterior material for the power storage device, a recess for accommodating the power storage device element may be formed by deep drawing molding or overhang molding. As shown in the example shown in FIG. 5, it is not necessary to provide a recess in one of the exterior materials for the power storage device and not in the exterior material for the other power storage device, and the other exterior material for the power storage device also has a recess. May be provided.

The exterior material for a power storage device of the present disclosure can be suitably used for a power storage device such as a battery (including a capacitor, a capacitor, etc.). Further, the exterior material for a power storage device of the present disclosure may be used for either a primary battery or a secondary battery, but is preferably used for a secondary battery. The type of the secondary battery to which the exterior material for the power storage device of the present disclosure is applied is not particularly limited, and for example, a lithium ion battery, a lithium ion polymer battery, an all-solid-state battery, a lead storage battery, a nickel / hydrogen storage battery, and a nickel / hydrogen storage battery. Examples thereof include cadmium storage batteries, nickel / iron storage batteries, nickel / zinc storage batteries, silver oxide / zinc storage batteries, metal air batteries, polyvalent cation batteries, capacitors, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries can be mentioned as suitable application targets of the exterior materials for power storage devices of the present disclosure.

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.

<Manufacturing of exterior materials for power storage devices>
Examples 1, 2, 5, 6, 8 and Comparative Example 1
Biaxially stretched nylon film as a base material layer (Ny 20 μm or 15 μm in thickness shown in Table 1) and aluminum foil as a barrier layer having corrosion-resistant films formed on both sides (JIS H4160: 1994 A8021HO, thickness 35 μm). ) Was prepared. As the base material layers used in Examples 1, 2, 5, 6, 8 and Comparative Example 1, those having the main axis orientations shown in Table 1 were used. The principal axis orientation of the base material layer is a value measured by the method described later. Next, a base material layer and a barrier layer are laminated by a dry laminating method using a two-component curable urethane adhesive (polyol compound and aromatic isocyanate compound), and an aging treatment is performed to obtain a base material layer (thickness). A laminate of 20 μm or 15 μm) / adhesive layer (thickness after curing was 3 μm) / barrier layer (thickness 35 μm) was prepared.

Next, on the barrier layer of the obtained laminate, maleic anhydride-modified polypropylene (PPa, thickness 15 μm) as an adhesive layer and polypropylene (PP, thickness 15 μm) as a heat-sealing resin layer are combined. By extruding, an adhesive layer / heat-sealing resin layer was laminated on the barrier layer. Next, by aging and heating the obtained laminate, a biaxially stretched nylon film / adhesive layer / barrier layer / adhesive layer / heat-sealing resin layer are laminated in this order as an exterior material for a power storage device. (Thickness shown in Table 1) was obtained.

Example 3
Biaxially stretched nylon film in the same manner as in Example 2 except that the thickness of the barrier layer was 30 μm, the thickness of the adhesive layer was 14 μm, and the thickness of the heat-sealing resin layer was 10 μm. / Adhesive layer / Barrier layer / Adhesive layer / Heat-sealing resin layer were laminated in this order to obtain an exterior material for a power storage device (thickness shown in Table 1).

Example 4
A two-component curable urethane resin (including silica particles (matting agent), polyol compound, and aromatic isocyanate compound) is used on the surface of the base material layer, and a surface coating layer (thickness) is used as the outermost layer of the exterior material for a power storage device. 3 μm) was formed, and a two-component curable urethane adhesive containing carbon black (including carbon black, polyol compound, and aromatic isocyanate compound) was used to form the adhesive layer between the base material layer and the barrier layer. Exterior for power storage device in which a surface coating layer / biaxially stretched nylon film / adhesive layer / barrier layer / adhesive layer / heat-sealing resin layer are laminated in this order in the same manner as in Example 3 except that they are used. A material (thickness shown in Table 1) was obtained.

Example 7
A surface coating layer (thickness) is used as the outermost layer of the exterior material for power storage devices by using a two-component curable urethane resin (including silica particles (matting agent), polyol compound, and aromatic isocyanate compound) on the surface of the base material layer. 3 μm) was formed, and a two-component curable urethane adhesive containing carbon black (including carbon black, polyol compound, and aromatic isocyanate compound) was used to form the adhesive layer between the base material layer and the barrier layer. Surface coating layer / biaxially stretched nylon film / adhesive in the same manner as in Example 6 except that it was used, the thickness of the adhesive layer was 14 μm, and the thickness of the heat-sealing resin layer was 10 μm. An exterior material for a power storage device (thickness shown in Table 1) was obtained in which an agent layer / a barrier layer / an adhesive layer / a heat-sealing resin layer were laminated in this order.

Erucic acid amide was applied as a lubricant to the outer surface of the base material layer of the exterior material for each power storage device.

<Measurement of spindle direction>
For the biaxially stretched nylon film used as the base material layer in each Example and Comparative Example, as shown in the schematic views of FIGS. 6 to 8, a spindle orientation measuring device provided with a camera C and a light source LS was used. The base material layer 1 is arranged between the camera C and the light source LS so that the camera C of the measuring device, the base material layer 1, and the light source LS are located in a straight line, and the direction of the TD of the base material layer 1 is set. The measurement was performed by irradiating the light L of the light source LS in the thickness direction D of the base material layer 1 with the 0 ° direction and the MD direction of the base material layer 1 as the 90 ° direction. As shown in the schematic views of FIGS. 6 and 7, in the measurement, the biaxially stretched nylon is transmitted from the light source arranged on the back side (the side opposite to the camera C side) of the biaxially stretched nylon film (base material layer 1). Light was irradiated in the thickness direction of the film. A transparent glass plate G was placed on the base material layer 1 (on the camera C side), and the measurement was performed so that no wrinkles were formed on the surface of the base material layer 1. Further, although not shown in FIGS. 6 to 8, the base material layer 1 and the glass plate G are arranged in this order on a plate provided with an opening at a position where the base material layer 1 is irradiated with light. The measurement was carried out so that the light L was transmitted through the base material layer 1 and the glass plate G through the opening of the plate. The measurement results are shown in Table 1. The specific measurement conditions are as follows.
(Measurement condition)
Measuring device: Polarized high-speed imaging device (CRYSTA PI-5) manufactured by Photron Co., Ltd.
Analysis software: KAMAKIRI offline basic software Ver: 1.5.0.1
Measurement sample: A biaxially stretched nylon film is cut into A4 size (TD210 mm × MD300 mm) to prepare.
Measurement wavelength (camera side): 520 to 570 nm (The camera that receives light through the film detects light with a wavelength of 520 to 570 nm)
Light source: White LED light (measurement samples are placed so that the positional relationship between the light source (light), the base material layer, and the camera coincides with the extension line of the light source and the thickness direction of the base material layer, and the camera is placed on the extension line of the light source. Is placed.)

<Evaluation of moldability>
The exterior material for the power storage device was cut into a rectangle having a length (direction of MD (Machine Direction)) of 90 mm × width (direction of TD (Transverse Direction)) of 150 mm to prepare a test sample. This sample is a rectangular molding die having a diameter of 31.6 mm (MD direction) x 54.5 mm (TD direction) (female mold, surface is JIS B 0659-1: 2002 Annex 1 (reference)). The maximum height roughness (nominal value of Rz) specified in Table 2 of the comparative surface roughness standard piece is 3.2 μm. Corner R2.0 mm, ridge line R1.0 mm) and the corresponding molding die. Mold (male type, surface is JIS B 0659-1: 2002 Annex 1 (reference) Maximum height roughness (nominal value of Rz) specified in Table 2 of the comparative surface roughness standard piece is 1.6 μm. (Corner R2.0 mm, ridge line R1.0 mm), the molding depth is changed from 0.5 mm molding depth at a pressing pressure (surface pressure) of 0.25 MPa in 0.5 mm increments, and 10 pieces each. Cold molding (pull-in one-stage molding) was performed on the sample of. At this time, the test sample was placed on the female mold so that the heat-sealing resin layer side was located on the male mold side, and molding was performed. The clearance between the male type and the female type was set to 0.3 mm. The cold-formed sample was exposed to light with a penlight in a dark room, and it was confirmed whether or not pinholes or cracks were generated in the aluminum alloy foil due to the transmission of light. The deepest molding depth where pinholes and cracks do not occur in all 10 samples of the aluminum alloy foil is Amm, and the number of samples where pinholes and the like occur at the shallowest molding depth where pinholes and the like occur in the aluminum alloy foil. Was taken as B pieces, and the value calculated by the following formula was rounded off to the second digit after the decimal point to obtain the limit molding depth of the exterior material for the power storage device. The depth reference was determined in four stages as follows, separately for the case where the thickness of the base material layer was 20 μm and the case where the thickness was 15 μm. The results are shown in Table 1.
Limit molding depth = Amm + (0.5mm / 10 pieces) x (10 pieces-B pieces)

(Evaluation criteria for moldability when the thickness of the base material layer is 20 μm)
A1: Limit molding depth is 7.5 mm or more B1: Limit molding depth is 7.0 mm or more and less than 7.5 mm C1: Limit molding depth is 6.5 mm or more and less than 7.0 mm D1: Limit molding depth is 6. Less than 5 mm

(Evaluation criteria for moldability when the thickness of the base material layer is 15 μm)
A2: Limit molding depth is 6.5 mm or more B2: Limit molding depth is 6.0 mm or more and less than 6.5 mm C2: Limit molding depth is 5.5 mm or more and less than 6.0 mm D2: Limit molding depth is 5. Less than 5 mm

It can be seen that the exterior materials for power storage devices of Examples 1 to 8 have excellent moldability because the predetermined principal axis orientation of the base material layer is within the range of 90 ° ± 30 °.

Further, when the phase difference of the base material layer was also measured in the above-mentioned measurement of the principal axis orientation, the phase difference of Example 1 was 72.9 nm, the phase difference of Example 2 was 196.4 nm, and the phase difference of Example 5 was measured. Is 205.1 nm, the phase difference of Example 6 is 49.8 nm, the phase difference of Example 8 is 123.7 nm, the phase difference of Comparative Example 1 is 228.7 nm, and even if the phase difference is 210 nm or less. It can be seen that the exterior material for the power storage device is excellent in moldability.

For reference, the tensile breaking strength (MPa) of each of the biaxially stretched nylon films used as the base material layer in Example 1 and Comparative Example 1 was measured, and the tensile breaking strength of Example 1 was MD. The tensile breaking strength of Comparative Example 1 was 284 MPa in the MD direction and 320 MPa in the TD direction, whereas the direction of 270 MPa and the direction of TD were 300 MPa. The base material layer of Comparative Example 1 had a higher tensile breaking strength than the base material layer of Example 1, but the moldability of the exterior material for the power storage device was higher in Comparative Example 1 than in Example 1. Was also inferior.

As described above, the present disclosure provides the inventions of the following aspects.
Item 1. It is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
The base material layer is an exterior material for a power storage device, which is measured by the following measuring method and has a principal axis orientation within the range of 90 ° ± 30 °.
[Measuring method]
A spindle orientation measuring device including a camera and a light source is used so that the camera, the base material layer, and the light source of the measuring device are located in a straight line, and the base material layer is formed between the camera and the light source. The thickness of the base material layer when the base material layer is arranged so that the TD direction of the base material layer is 0 ° and the MD direction of the base material layer is 90 °. The light of the light source is irradiated in the direction, and the principal axis orientation of the base material layer is measured.
Item 2. Item 2. The exterior material for a power storage device according to Item 1, wherein the base material layer has a thickness of 10 μm or more and 30 μm or less.
Item 3. Item 2. The exterior material for a power storage device according to

Item

1 or 2, wherein the base material layer contains at least one of a polyamide film and a polyester film.
Item 4. Item 2. The exterior material for a power storage device according to any one of Items 1 to 3, wherein the thickness of the laminated body is 100 μm or less.
Item 5. A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for the power storage device according to any one of Items 1 to 4.
Item 6. At least, it includes a step of laminating the base material layer, the barrier layer, and the heat-sealing resin layer in this order to obtain a laminate.
The base material layer is a method for manufacturing an exterior material for a power storage device, in which the principal axis direction is within the range of 90 ° ± 30 °, which is measured by the following measuring method.
[Measuring method]
A spindle orientation measuring device including a camera and a light source is used so that the camera, the base material layer, and the light source of the measuring device are located in a straight line, and the base material layer is formed between the camera and the light source. When the TD direction of the base material layer is 0 ° and the MD direction of the base material layer is 90 °, the light of the light source is irradiated in the thickness direction of the base material layer. Then, the principal axis direction of the base material layer is measured.
Item 7. It is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
The base material layer is an exterior material for a power storage device having a phase difference of 210 nm or less, which is measured by the following measuring method.
[Measuring method]
A spindle orientation measuring device including a camera and a light source is used so that the camera, the base material layer, and the light source of the measuring device are located in a straight line, and the base material layer is formed between the camera and the light source. The thickness of the base material layer when the base material layer is arranged so that the TD direction of the base material layer is 0 ° and the MD direction of the base material layer is 90 °. The light of the light source is irradiated in the direction, and the phase difference of the base material layer is measured.

1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Heat-sealing resin layer 5 Adhesive layer 6 Surface coating layer 10 Exterior material for power storage devices

Claims

It is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealing resin layer in this order.
The base material layer is an exterior material for a power storage device, which is measured by the following measuring method and has a principal axis orientation within the range of 90 ° ± 30 °.
[Measuring method]
A spindle orientation measuring device including a camera and a light source is used so that the camera, the base material layer, and the light source of the measuring device are located in a straight line, and the base material layer is formed between the camera and the light source. The thickness of the base material layer when the base material layer is arranged so that the TD direction of the base material layer is 0 ° and the MD direction of the base material layer is 90 °. The light of the light source is irradiated in the direction, and the principal axis orientation of the base material layer is measured.
The exterior material for a power storage device according to claim 1, wherein the thickness of the base material layer is 10 μm or more and 30 μm or less.
The exterior material for a power storage device according to claim 1 or 2, wherein the base material layer contains at least one of a polyamide film and a polyester film.
The exterior material for a power storage device according to any one of claims 1 to 3, wherein the thickness of the laminated body is 100 μm or less.
A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for the power storage device according to any one of claims 1 to 4.
At least, it includes a step of laminating the base material layer, the barrier layer, and the heat-sealing resin layer in this order to obtain a laminate.
The base material layer is a method for manufacturing an exterior material for a power storage device, in which the principal axis direction is within the range of 90 ° ± 30 °, which is measured by the following measuring method.
[Measuring method]
A spindle orientation measuring device including a camera and a light source is used so that the camera, the base material layer, and the light source of the measuring device are located in a straight line, and the base material layer is formed between the camera and the light source. The thickness of the base material layer when the base material layer is arranged so that the TD direction of the base material layer is 0 ° and the MD direction of the base material layer is 90 °. The light of the light source is irradiated in the direction, and the principal axis orientation of the base material layer is measured.