JP2020155364A - Exterior material for power storage device, manufacturing method of the same, and power storage device - Google Patents

Abstract

To provide an exterior material for a power storage device, capable of preventing peeling of a colored layer containing carbon black, having high rigidity, and unlikely to form wrinkles when peeling a tape, even when the exterior material for a power storage device is used in a hot and humid environment.SOLUTION: An exterior material for a power storage device is composed of a laminate, including at least a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer, in this order. The colored layer is a cured material of a composition containing carbon black, diamine, polyol, and a curing agent. In the colored layer, the content of the curing agent is 2 mass parts or more and 20 mass parts or less in the total of 100 mass parts of the carbon black, the diamine, and the polyol.SELECTED DRAWING: None

Description

The present disclosure relates to an exterior material for a power storage device, a method for manufacturing the same, and a power storage device.

Conventionally, various types of power storage devices have been developed, but in all power storage devices, an exterior material is an indispensable member for sealing a power storage device element such as an electrode or an electrolyte. 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 increase in 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, in recent years, 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 layer / barrier layer / thermosetting resin layer is sequentially laminated. Laminates have been proposed (see, for example, Patent Document 1).

In such an exterior material for a power storage device, a recess is generally formed by cold forming, 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 thermosetting resin. By heat-sealing the layers, a power storage device in which the power storage device element is housed inside the exterior material for the power storage device can be obtained.

Japanese Unexamined Patent Publication No. 2008-287971

In recent years, in order to further increase the energy density of the power storage device and further reduce the size of the power storage device, there is a demand for further thinning of the exterior material for the power storage device. On the other hand, when manufacturing a power storage device, transporting a product equipped with a power storage device, or when using the product, a large impact may be applied to the product. At this time, a large external force may be applied from the inside or the outside to the exterior material for the power storage device that houses the power storage device element.

Along with the demand for thinner exterior materials for power storage devices, thinning of the barrier layer is also being considered. Although aluminum foil has excellent moldability, it has low rigidity and is large from the inside or outside of the exterior material for power storage devices. When an external force is applied, the aluminum foil may be punctured and the power storage device element may be exposed to the outside.

Further, in the manufacturing process of the power storage device, from the viewpoint of suppressing the surface of the power storage device from being scratched, the surface of the power storage device (that is, the surface of the exterior material for the power storage device that seals the power storage device element) The masking tape may be affixed and peeled off before the power storage device is used. Further, the power storage device may be fixed to a housing or the like using tape or the like. For example, the tape may be peeled off from the surface of the power storage device in order to correct the position of the tape once attached. is there. When the tape is peeled off from the surface of the power storage device in this way, the exterior material for the power storage device follows the tape to form wrinkles on the surface of the power storage device, and the wrinkles cause the exterior material for the power storage device and the positive electrode / separator / negative electrode. There may be a gap between the cell and the cell. Then, the electrolytic solution moves from the cell to the void, which causes deterioration of the performance of the energy storage device, and when the cell is vibrated due to the formation of the void, the exterior material for the energy storage device comes into contact with the cell, and the energy storage device. The thermosetting resin layer of the exterior material may be scratched and cause corrosion.

Further, a power storage device such as a lithium ion secondary battery is often required to be colored in order to unify the appearance and color of the device such as an electric device to be mounted. For example, in order to give a profound feeling and a sense of quality, the device is often colored black, and in this case, the power storage device is also often colored black. In order to color the power storage device to black or the like, there are means such as coloring the resin layer used for the exterior material for the power storage device, providing a printing layer under the base resin layer, and the like.

However, when a printing layer containing carbon black as a pigment is provided on the inner surface of the outer resin layer constituting the exterior material in order to color the power storage device black, the exterior material is subjected to deep drawing molding or overhang molding to form a container (case). ) When molding into a shape, the carbon black-containing printing layer is peeled off, and the underlying layer is exposed, so that uniform black coloring is impaired. Such peeling of the print layer also occurs when the black exterior material is sealed after the electrodes and the electrolytic solution are sealed, and when the power storage device packaged with the black exterior material is used in a high temperature and high humidity environment.

Under such circumstances, the present disclosure suppresses peeling of the colored layer containing carbon black even when the exterior material for a power storage device is used in a high temperature and high humidity environment, and is further high. The main purpose is to provide an exterior material for a power storage device that has rigidity and is less likely to form wrinkles when the tape is peeled off. A further object of the present disclosure is to provide a method for manufacturing an exterior material for a power storage device, and a power storage device using the exterior material for the power storage device.

The inventors of the present disclosure have made diligent studies to solve the above problems. As a result, it is composed of a laminate including at least a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer in this order, and the colored layer is composed of carbon black, diamine, polyol, and It is a cured product of a composition containing a curing agent, and the content of the curing agent in the colored layer is 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass in total of carbon black, diamine, and polyol. The exterior material for the power storage device is prevented from peeling off the colored layer containing carbon black even when the exterior material for the power storage device is used in a hot and humid environment, and further has high rigidity. It was found that wrinkles are unlikely to be formed when the tape is peeled off.

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 including at least a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer in this order.
The colored layer is a cured product of a composition containing carbon black, diamine, polyol, and a curing agent.
In the colored layer, the content of the curing agent is 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass in total of carbon black, diamine, and polyol, which is an exterior material for a power storage device.

According to the present disclosure, in the exterior material for a power storage device composed of a laminate including a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer in this order, the exterior material for the power storage device is Even when used in a hot and humid environment, the colored layer containing carbon black is suppressed from peeling off, and it has high rigidity, and wrinkles are formed when the tape is peeled off. It is possible to provide a difficult exterior material for a power storage device. 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 evaluation method of the tape peelability in an Example.

The exterior material for a power storage device of the present disclosure is composed of at least a laminate including a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer in this order, and the colored layer is carbon. It is a cured product of a composition containing black, diamine, polyol, and a curing agent, and the content of the curing agent in the colored layer is 2 parts by mass or more with respect to 100 parts by mass in total of carbon black, diamine, and polyol. It is characterized in that it is 20 parts by mass or less. According to the exterior material for a power storage device of the present disclosure, by providing the above configuration, a press pressure is applied to the power storage device obtained by sealing the power storage device element with the exterior material for the power storage device. Even in such a case, high insulation can be exhibited.

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.

1. 1. Laminated structure of exterior material for power storage device The exterior material 10 for power storage device of the present disclosure includes, for example, a base material layer 1, a colored layer 2, a stainless steel foil 3, and a thermosetting resin layer 4, as shown in FIG. It is composed of a laminated body provided in this order. In the exterior material 10 for a power storage device, the base material layer 1 is on the outermost layer side, and the thermosetting 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 thermosetting 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.

As shown in FIGS. 2 to 4, for example, the exterior material 10 for a power storage device is used as necessary for the purpose of enhancing the adhesiveness between the base material layer 1 and the stainless steel foil 3 and the like. May have an adhesive layer 21. The adhesive layer 21 may be arranged between the colored layer 2 and the stainless steel foil 3, or may be arranged between the colored layer 2 and the base material layer 1. 2 to 4 show a mode in which the adhesive layer 21 is arranged between the colored layer 2 and the stainless steel foil 3. Further, for example, as shown in FIGS. 3 and 4, an adhesive layer is required between the stainless steel foil 3 and the thermosetting resin layer 4 for the purpose of enhancing the adhesiveness between the layers. May have 5. 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 thermosetting resin layer 4 side), if necessary.

As for the thickness of the laminate constituting the exterior material for the power storage device of the present disclosure, the power storage device has high rigidity while being a thin exterior material for the power storage device, and wrinkles are unlikely to be formed when the tape is peeled off. From the viewpoint of the exterior material, it is preferably about 45 μm or more, more preferably about 50 μm or more, further preferably 55 μm or more, and preferably about 120 μm or less, preferably about 91 μm or less, preferably about 86 μm or less. .. The preferable range of the thickness of the laminate is about 45 to 120 μm, about 45 to 91 μm, about 45 to 86 μm, about 50 to 120 μm, about 50 to 91 μm, about 50 to 86 μm, about 55 to 120 μm, and about 55 to 91 μm. It is about 55 to 86 μm, and among these, about 50 to 86 μm, more preferably about 55 to 86 μm. The thickness of the laminated body constituting the exterior material 10 for the power storage device can be measured by using a commercially available thickness measuring device.

Further, the bending stiffness of the laminate constituting the exterior material for the power storage device of the present disclosure is preferably in the range of 0.60 to 6.0 gf · cm ² / cm. By setting the bending stiffness of the laminate constituting the exterior material for the power storage device of the present disclosure within such a specific range, excellent moldability can be exhibited, and the tape can be peeled off. At the same time, the formation of wrinkles can be suppressed more effectively.

The bending stiffness is preferable from the viewpoint of exhibiting excellent moldability while reducing the thickness of the exterior material for the power storage device and further effectively suppressing the formation of wrinkles when the tape is peeled off. Is about 0.60 gf · cm ² / cm or more, more preferably about 0.65 gf · cm ² / cm or more, still more preferably about 0.70 gf · cm ² / cm or more, still more preferably about 0.80 gf · cm ² It is more than / cm, preferably about 6.0 gf · cm ² / cm or less, more preferably about 1.60 gf · cm ² / cm or less, still more preferably about 1.55 gf · cm ² / cm or less. .. Preferred ranges of the bending stiffness, 0.60~6.0gf · cm ² / cm approximately, 0.65~6.0gf · cm ² / cm approximately, 0.70~6.0gf · cm ² / cm about , 0.80 to 6.0 gf ・ cm ² / cm, 0.60 to 1.55 gf ・ cm ² / cm, 0.65 to 1.60 gf ・ cm ² / cm, 0.65 to 1.55 gf・ Cm ² / cm, 0.70 to 1.60 gf ・ cm ² / cm, 0.70 to 1.55 gf ・ cm ² / cm, 0.80 to 1.60 gf ・ cm ² / cm, 0 Approximately 80 to 1.55 gf · cm ² / cm can be mentioned.

The bending stiffness of the laminated body constituting the exterior material 10 for the power storage device can be adjusted by, for example, the thickness and composition of the layers constituting the laminated body.

In the present disclosure, the method for measuring the bending stiffness of the laminate constituting the exterior material for the power storage device is as follows. Specifically, it can be measured by the method described in Examples.

<Measurement of bending stiffness>
A test sample is obtained by cutting the exterior material for a power storage device into a rectangle having a width (direction perpendicular to the flow direction during film formation: TD) of 80 mm and a length (flow direction during film formation: MD) of 100 mm. Bending stiffness (gf · cm ² / cm) is measured for the obtained test sample using a commercially available bending stiffness measuring machine. The measurement conditions were a curvature change rate of 0.1 / cm · sec, a clamp interval of 1 cm, and a maximum curvature of 2.5 cm ^-1 , and the average value of bending stiffness (rigid bending stiffness) for 10 test samples was taken. , The bending stiffness of the exterior material for power storage devices. The test sample is fixed to two clamps so that the edge having a width of 80 mm coincides with the direction of the clamp axis.

From the viewpoint of exhibiting excellent moldability while reducing the thickness of the exterior material for the power storage device and further effectively suppressing the formation of wrinkles when the tape is peeled off, the exterior material for the power storage device of the present disclosure is disclosed. The laminated body constituting the material preferably has a piercing strength of 15 N or more when pierced from the base material layer side, which is measured by a method in accordance with JIS Z1707: 1997. It is more preferable that it is within the range.

In the present disclosure, the method for measuring the piercing strength of the laminate constituting the exterior material 10 for the power storage device is as follows. Specifically, it can be measured by the method described in Examples.

<Measurement of piercing strength>
The piercing strength from the base material layer side of the laminate constituting the exterior material for the power storage device is measured by a method in accordance with the provisions of JIS Z1707: 1997. Specifically, in a measurement environment of 23 ± 2 ° C. and relative humidity (50 ± 5)%, the test piece is fixed with a table having a diameter of 115 mm and a holding plate having an opening of 15 mm in the center, and the diameter is 1.0 mm. , A semi-circular needle with a tip shape radius of 0.5 mm is pierced at a speed of 50 ± 5 mm per minute, and the maximum stress until the needle penetrates is measured. The number of test pieces is 5, and the average value is calculated. If the number of test pieces is insufficient and 5 cannot be measured, the measurable number is measured and the average value is calculated.

Examples of the tape for fixing the power storage device to the housing or the like include rubber-based components, acrylic-based components, urethane-based components, silicone-based components, and styrene-isoprene block copolymer (SIS) -based components as adhesive components. Adhesive tapes using the above can be mentioned, and commercially available products of such adhesive tapes are easily available.

2. 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 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 an insulating property. The base material layer 1 can be formed by using, for example, a resin, and the resin may contain an additive described later.

When the base material layer 1 is made of a resin, 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 may be a modified product of the copolymer. Further, it may be a mixture of these resins.

Among these, preferable examples of the resin forming the base material layer 1 include polyester and 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. 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.

Further, as the polyamide, specifically, an aliphatic polyamide such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, 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) containing the derived structural units. 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 a polyester or a 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 polypropylene film, and a stretched polyolefin film. It is more preferable to contain at least one of stretched polyethylene terephthalate film, stretched polybutylene terephthalate film, stretched nylon film and stretched polypropylene film, and biaxially stretched polyethylene terephthalate film, biaxially stretched polybutylene terephthalate film, biaxially stretched nylon film. , It is more preferable to contain at least one of the biaxially stretched polypropylene films.

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 laminate 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.

As a specific example of a laminate of two or more layers of resin film in the base material layer 1, 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. Preferred adhesives include the same adhesives as those exemplified in the adhesive layer 21 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 21 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, palmitate amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide and the like. Specific examples of unsaturated fatty acid amides include oleic acid amides and erucic acid amides. Specific examples of the substituted amide include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucate amide and the like. Further, specific examples of methylolamide include methylolstearic acid amide. Specific examples of the saturated fatty acid bisamide 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 amides, hexamethylene bisbechenic acid amides, hexamethylene hydroxystearic acid amides, N, N'-distearyl adipate amides, and N, N'-distealyl sebasic acid amides. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid 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.

If a lubricant on the surface of the base material layer 1 is present, as it is its abundance is not particularly limited, preferably about 3 mg / m ² or more, more preferably 4~15mg / m ² approximately, more preferably 5~14mg / 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, and examples thereof include about 3 to 50 μm, about 3 to 35 μm, and about 3 to 25 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.

[Colored layer 2]
The colored layer 2 is a layer provided between the base material layer 1 and the stainless steel foil 3. When the adhesive layer 21 is provided, the colored layer 2 may be provided between the base material layer 1 and the adhesive layer 21, or at least one of the adhesive layer 21 and the stainless steel foil 3. .. In the exterior material for a power storage device of the present disclosure, the exterior material for a power storage device can be colored black by providing the black coloring layer 2.

In the present disclosure, the colored layer 2 is a cured product of a composition containing carbon black, diamine, polyol and a curing agent. Further, in the colored layer 2, the content of the curing agent is 2 to 20 parts by mass with respect to 100 parts by mass in total of carbon black, diamine, and polyol. If the amount of the curing agent is less than 2 parts by mass, peeling is likely to occur between the stainless steel foil 3 and the colored layer 2 when molding the exterior material for the electricity storage device, and if the amount of the curing agent exceeds 20 parts by mass, the electricity is stored in the wound state. Blocking is likely to occur when the exterior material for a device is unwound, and problems such as transfer and adhesion to the outer surface of the base material layer 1 and the thermosetting resin layer 4 are likely to occur.

Further, it is preferable that the content of carbon black in the colored layer 2 is 15 to 60% by mass, and the total content of the diamine, the polyol and the curing agent is about 40 to 85% by mass. Above all, the content of carbon black is preferably 20 to 50% by mass. When the content of carbon black is less than 15% by mass, the metallic luster due to the stainless steel foil 2 is easily visible from the base material layer 1, the profound feeling due to black is impaired, and when the exterior material for the power storage device is molded. , Partial color unevenness is likely to occur. On the other hand, when the content of carbon black exceeds 60% by mass, the colored layer 2 tends to be hard and brittle, so that the adhesive force to the stainless steel foil 3 decreases, and the stainless steel foil 3 and the colored layer 2 are formed during molding. Peeling is likely to occur between them.

The thickness of the colored layer 2 is preferably about 1 to 4 μm. When the thickness is 1 μm or more, the color tone of the colored layer 2 does not remain transparent, and the color and gloss of the stainless steel foil 3 can be sufficiently concealed by black. Further, when the thickness is 4 μm or less, cracking of the colored layer 2 can be more effectively suppressed during molding.

The method for forming the colored layer 2 is not particularly limited, and examples thereof include a gravure printing method, a reverse roll coating method, and a lip roll coating method.

For the colored layer 2, for example, a composition for forming a colored layer (ink composition) containing carbon black, diamine, polyol, a curing agent, and an organic solvent is applied by a gravure printing method to the base material layer 1 or the stainless steel foil 3 (necessarily). Correspondingly, it can be formed by printing (coating) on the surface of (which may be subjected to a chemical conversion treatment described later), drying, and curing. The organic solvent is not particularly limited, and examples thereof include toluene and the like.

As the carbon black, it is preferable to use one having an average particle size of 10 to 500 μm. The average particle size of carbon black shall be the median size measured by a laser diffraction / scattering type particle size distribution measuring device.

The diamine is not particularly limited, and examples thereof include ethylenediamine, dimerdiamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, dicyclohexylmethanediamine, and 2-hydroxyethylpropylenediamine. Among them, as the diamine, it is preferable to use one or more diamines selected from the group consisting of ethylenediamine, dimer diamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine and dicyclohexylmethanediamine.

Diamine has a faster reaction rate with a curing agent (isocyanate compound, etc.) than polyol, and can be cured in a short time. That is, the diamine reacts with the curing agent together with the polyol to promote cross-linking and curing of the composition for forming a colored layer (ink composition).

The polyol is not particularly limited, but it is preferable to use one or more of the polyols selected from the group consisting of polyurethane-based polyols, polyester-based polyols and polyether-based polyols.

The number average molecular weight of the polyol is preferably in the range of 1000 to 8000. When the number average molecular weight of the polyol is 1000 or more, the adhesive strength after curing can be increased, and when it is 8000 or less, the reaction rate with the curing agent can be increased. The number average molecular weight of the polyol is a standard polystyrene equivalent molecular weight measured using gel permeation chromatography.

The curing agent is not particularly limited, and examples thereof include isocyanate compounds. As the isocyanate compound, for example, various aromatic, aliphatic, and alicyclic isocyanate compounds can be used. Specific examples include tolylene diisocyanate (TDI), diphenylmethane diisocyanate, hexamethylene diisocyanate (HDI), isophorone diisocyanate and the like.

[Adhesive layer 21]
In the exterior material for a power storage device of the present disclosure, the adhesive layer 21 is a layer provided between the base material layer 1 and the stainless steel foil 3 as necessary for the purpose of enhancing the adhesiveness between them. .. The adhesive layer 21 may be arranged between the colored layer 2 and the stainless steel foil 3, or may be arranged between the colored layer 2 and the base material layer 1.

The adhesive layer 21 is formed by an adhesive capable of adhering the base material layer 1 and the stainless steel foil 3 with the colored layer 2 interposed therebetween. That is, the adhesive layer 21 has adhesiveness to the colored layer 2 and adhesiveness to the base material layer 1 or the stainless steel foil 3. The adhesive used for forming the adhesive layer 21 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 21 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; (Meta) acrylic resin; Polyethylene; Polyolefin; 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. As the curing agent, an appropriate one 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 main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred are two-component curable polyurethane adhesives containing a polyol such as a polyester polyol, a polyether polyol, and an acrylic polyol as a main component and an aromatic or aliphatic polyisocyanate as a curing agent. Further, 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. Since the adhesive layer 21 is formed of the polyurethane adhesive, excellent electrolyte resistance is imparted to the exterior material for the power storage device, and even if the electrolyte adheres to the side surface, the base material layer 1 is suppressed from peeling off. ..

Further, the adhesive layer 21 may contain a colorant, a thermoplastic elastomer, a tackifier, a filler, etc., as long as the adhesiveness is not hindered, the addition of other components is permitted. Since the adhesive layer 21 contains a colorant, the exterior material for the power storage device can be colored. As the colorant, known pigments, dyes and the like 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 21. 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 together with the color layer 2.

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 diameter measured by a laser diffraction / scattering type particle size distribution measuring device.

The content of the pigment in the adhesive layer 21 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 21 is not particularly limited as long as it can be bonded by interposing the base material layer 1, the stainless steel foil 3, and the colored layer 2, but for example, it is about 1 μm or more, about 2 μm or more, and about 10 μm or less. , About 5 μm or less. Preferred ranges include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[Stainless steel foil 3]
In the exterior material for the power storage device of the present disclosure, the stainless steel foil 3 functions as a barrier layer for improving the strength of the exterior material for the power storage device and preventing water vapor, oxygen, light, etc. from entering the inside of the power storage device. It is a layer to do.

Examples of the stainless steel foil 3 include austenitic stainless steel foil and ferritic stainless steel foil. In the present disclosure, the stainless steel foil 3 is an austenitic stainless steel foil 3 from the viewpoint of providing an exterior material for a power storage device which has high rigidity, is less likely to form wrinkles when the tape is peeled off, and has excellent moldability. It is preferably made of stainless steel.

Specific examples of the austenitic stainless steel constituting the stainless steel foil 3 include SUS304, SUS301, and SUS316L. Among these, a power storage device having high piercing strength and excellent electrolytic solution resistance and moldability. From the viewpoint of using as an exterior material, SUS304 is particularly preferable.

The thickness of the stainless steel foil 3 is not particularly limited, but the exterior material for the electricity storage device is further thinned, has high piercing strength, and has excellent electrolytic solution resistance and moldability. From this point of view, preferably 40 μm or less, about 10 to 40 μm, about 10 to 30 μm, about 15 to 25 μm, and the like can be mentioned.

Further, it is preferable that the stainless steel foil 3 is provided with a corrosion-resistant film at least on the surface opposite to the base material layer in order to prevent melting and corrosion. The stainless steel foil 3 may have 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 to a stainless steel foil. A thin film that is applied to the surface to make stainless steel foil corrosion resistant. 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 anodic oxidation treatment are treatments in which the surface of the metal foil is dissolved by a 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 stainless steel foil 3 has a corrosion-resistant film, the stainless steel foil 3 includes the corrosion-resistant film.

The corrosion-resistant film is formed on the surface of the stainless steel foil by preventing delamination between the stainless steel foil and the base material layer and hydrogen fluoride generated by the reaction between the electrolyte and water during molding of the exterior material for the power storage device. Prevents melting, and improves the adhesiveness (wetability) of the stainless steel foil surface, prevents delamination between the base material layer and stainless steel foil during heat sealing, and prevents the base material layer and stainless steel foil during molding. Shows the effect of preventing delamination with.

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 include a corrosion-resistant film containing. Examples of the chemical conversion treatment using a phosphate or a chromate include a chromate chromate treatment, a phosphoric chromate treatment, a phosphoric acid-chromate treatment, a chromate treatment, and the like, and chromium used in these treatments. Examples of the compound include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium dichromate, acetylacetate chromate, chromium chloride, and chromium potassium sulfate. 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 stainless steel foil is first degreased by a well-known treatment method such as an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, and an acid activation method. After that, metal phosphate salts such as Cr (chromium) phosphate salt, Ti (titanium) phosphate salt, Zr (zylzine) phosphate, Zn (zinc) phosphate salt and their metals are placed on the degreased surface. A treatment liquid containing a mixture of salts as a main component, or a treatment liquid containing a mixture of a non-metal phosphoric acid salt and these non-metal salts as a main component, or a treatment liquid consisting of a mixture of these and a synthetic resin or the like. Is a process of coating and drying by a well-known coating method such as a roll coating method, a gravure printing method, or a dipping method. 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 resin and acrylic-based resin, and an aminoated phenol polymer having a repeating unit represented by the following general formulas (1) to (4). Examples thereof include the chromate treatment used. In the aminated 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 acrylic acid and a dicarboxylic acid or a dicarboxylic acid anhydride, and an ammonium salt, a sodium salt, or 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 linear or branched alkyl groups having 1 to 4 carbon atoms such as tert-butyl groups. Examples of the hydroxyalkyl groups represented by X, R ¹ and R ² include hydroxymethyl groups, 1-hydroxyethyl groups, 2-hydroxyethyl groups, 1-hydroxypropyl groups, 2-hydroxypropyl groups 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 aminated 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 aminated 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 rare earth element oxide sol, anionic polymer, and 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, neodymium 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 solvent, hydrocarbon solvent, ketone solvent, ester solvent, ether solvent and the like 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, the phosphoric acid or phosphate is preferably condensed phosphoric acid or condensed phosphate.

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

If necessary, 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. 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 stainless steel foil 3 in the chemical conversion treatment is not particularly limited, but for example, in the case of performing the coating type chromate treatment, chrome per 1 m ² of the surface of the stainless steel foil 3. The acid compound 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 aminoated phenol. It is desirable that the polymer is 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, from the viewpoint of the cohesive force of the film and the adhesion to the stainless steel foil or the thermosetting resin layer. About 100 nm, 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 a stainless steel foil by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then the stainless steel foil is applied. It is carried out by heating so that the temperature of is about 70 to 200 ° C. Further, before the stainless steel foil is subjected to the chemical conversion treatment, the stainless steel foil 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 stainless steel foil. 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 fluoride of the metal which is immobile. In this case, only the degreasing treatment may be performed.

[Thermosetting resin layer 4]
In the exterior material for a power storage device of the present disclosure, the thermosetting 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 thermosetting 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). Polypropylene such as (block copolymer of ethylene), random copolymer of polypropylene (for example, random copolymer of propylene and ethylene); propylene-α-olefin copolymer; terpolymer of ethylene-butene-propylene and the like. 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 which is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. .. 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.

The acid-modified polyolefin is a polymer modified by block-polymerizing or graft-polymerizing a 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. is there. The same applies to the cyclic polyolefins that are acid-modified. The acid component used for the acid modification is the same as the acid component used for the modification 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 thermosetting 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 thermosetting 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 thermosetting 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 thermosetting resin layer 4, the abundance thereof 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 thermosetting resin layer 4 may be one in which the lubricant contained in the resin constituting the thermosetting resin layer 4 is exuded, or the lubricant contained in the thermosetting resin layer 4 may be exuded. The surface may be coated with a lubricant.

The thickness of the thermosetting resin layer 4 is not particularly limited as long as the thermosetting resin layers have a function of heat-sealing to seal the power storage device element, but is preferably about 100 μm or less, preferably. 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 thermosetting 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 thermosetting 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 stainless steel foil 3 (or the acid-resistant film) and the thermosetting resin layer 4 as necessary in order to firmly bond them. It is a layer to be.

The adhesive layer 5 is formed of a resin capable of adhering the stainless steel foil 3 and the thermosetting resin layer 4 to each other. 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. The resin used for forming the adhesive layer 5 preferably contains a polyolefin skeleton, and examples thereof include the polyolefins exemplified in the above-mentioned heat-sealing resin layer 4 and acid-modified polyolefins. 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, when the resin constituting the adhesive layer 5 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. 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.

From the viewpoint of firmly adhering the stainless steel foil 3 and the heat-sealing resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. As the acid-modified polyolefin, a polyolefin modified with a carboxylic acid or an anhydride thereof, a polypropylene modified with a carboxylic acid or an anhydride thereof, a maleic anhydride-modified polyolefin, and a maleic anhydride-modified polypropylene are particularly preferable.

Further, from the viewpoint of reducing the thickness of the exterior material for the power storage device and making it an exterior material for the power storage device having excellent shape stability after molding, the adhesive layer 5 is a resin composition containing an acid-modified polyolefin and a curing agent. It is more preferable that it is a cured product of. As the acid-modified polyolefin, the above-mentioned ones are preferably exemplified.

Further, 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 it is a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. 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 amide ester resin is preferable. The amide ester resin is generally produced by the reaction of a carboxyl group and an oxazoline group. The adhesive layer 5 is more preferably a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. When an unreacted product 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 material 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 stainless steel foil 3 and the adhesive layer 5, the adhesive layer 5 is selected from the group consisting of oxygen atoms, heterocycles, C = N bonds, and COC bonds. It is preferably a cured product of a resin composition containing at least one curing agent. 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—O—C bond include a curing agent having an oxazoline group, a curing agent having an epoxy group, and polyurethane. 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 a polyfunctional isocyanate compound is preferable from the viewpoint of effectively enhancing the adhesion between the stainless steel foil 3 and the adhesive layer 5. 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 stainless steel foil 3 and the adhesive layer 5 can be effectively improved.

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. In addition, 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 stainless steel foil 3 and the adhesive layer 5 can be effectively improved.

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 derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, and polyglycerin polyglycidyl ether. 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 stainless steel foil 3 and the adhesive layer 5 can be effectively improved.

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, 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 stainless steel foil 3 and the adhesive layer 5 can be effectively enhanced in an atmosphere in which a component that induces corrosion of the stainless steel foil 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 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, about 5 μm or less, and preferably about 0.1 μm or more and about 0.5 μm or more. The thickness range 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, about 0.1 to 5 μm, and 0. Examples thereof include about 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 thermosetting 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. As a result, the adhesive layer 5 can be formed. Further, when the resin exemplified in the thermosetting resin layer 4 is used, it can be formed by, for example, extrusion molding of the thermosetting 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 stainless steel foil 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 main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferred are two-component curable polyurethanes containing a polyol such as a polyester polyol, a polyether polyol, and an acrylic polyol as a main component and an aromatic or aliphatic polyisocyanate as a curing agent. Further, 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. Since the surface coating layer 6 is made of polyurethane, excellent electrolyte resistance is imparted to the exterior material for the power storage device.

On at least one of the surface and the inside of the surface coating layer 6, the surface coating layer 6 is provided with the above-mentioned lubricant or anti, if necessary, depending on the surface coating layer 6 and the functionality to be provided on 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 diameter of about 0.5 nm to 5 μm. The average particle size of the additive shall be the median diameter measured by a 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 spherical, fibrous, plate-like, amorphous, and scaly shapes.

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 disclosure is laminated can be obtained, and at least a base material is used. Examples thereof include a method including a step of laminating the layer 1, the colored layer 2, the stainless steel foil 3, and the thermosetting resin layer 4 in this order. In the method for producing the exterior material 10 for a power storage device of the present disclosure, the colored layer 2 is a cured product of a composition containing carbon black, diamine, polyol, and a curing agent, and the content of the curing agent in the colored layer 2 is , 2 parts by mass or more and 20 parts by mass or less with respect to a total of 100 parts by mass of carbon black, diamine, and polyol. The details of the exterior material 10 for the power storage device of the present disclosure are as described above.

An example of the method for manufacturing the exterior material for the power storage device of the present disclosure is as follows. First, a laminate (hereinafter, may be referred to as "laminate A") in which the base material layer 1, the colored layer 2, the adhesive layer 21, and the stainless steel foil 3 are laminated in this order is formed. The laminate A is formed by, for example, forming an adhesive using a base material layer 1 provided with a colored layer 2 and a stainless steel foil 3 whose surface has been chemically converted, if necessary, to form an adhesive layer 21. Can be carried out by the dry laminating method.

Next, the thermosetting resin layer 4 is laminated on the stainless steel foil 3 of the laminated body A. When the heat-sealing resin layer 4 is directly laminated on the stainless steel foil 3, the heat-sealing resin layer 4 is laminated on the stainless steel foil 3 of the laminate A by a method such as a thermal laminating method or an extrusion laminating method. It may be laminated by. When the adhesive layer 5 is provided between the stainless steel foil 3 and the heat-sealing resin layer 4, for example, (1) the adhesive layer 5 and the heat-sealing property are placed on the stainless steel foil 3 of the laminate A. A method of laminating by extruding the resin layer 4 (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 is laminated. A method of laminating on the stainless steel foil 3 of the body A by a thermal laminating method or a laminated body in which the adhesive layer 5 is laminated on the stainless steel foil 3 of the laminated body A is formed, and this is combined with the heat-sealing resin layer 4. A method of laminating by the thermal laminating method, (3) While pouring the molten adhesive layer 5 between the stainless steel foil 3 of the laminated body A and the heat-sealing resin layer 4 which has been formed into a sheet in advance, A method of laminating the laminate A and the heat-sealing resin layer 4 via the adhesive layer 5 (sandwich laminating method), (4) Adhesion for forming the adhesive layer 5 on the stainless steel foil 3 of the laminate A. Examples thereof include a method of coating the agent with a solution and drying it, a method of laminating it by a method of baking, 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 stainless steel foil 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 stainless steel foil 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 stainless steel foil 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 colored layer 2 / the adhesive layer 21 provided as needed / the stainless steel foil 3 / the adhesive layer provided as needed A laminate having 5 / heat-sealing resin layers 4 in this order is formed, but in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as needed, further heat treatment is performed. May be served.

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 stainless steel foil 3, the printability of 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 in a state in which metal terminals connected to each of the positive electrode and the negative electrode are projected outward in the exterior material for the power storage device of the present disclosure. , 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 thermosetting 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 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 the power storage device of the present disclosure may be used for either a primary battery or a secondary battery, but is preferably 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>
Example 1
The composition for forming a colored layer having the composition A shown in Table 1 is printed on a base material layer 1 made of a stretched nylon film (ONY thickness 10 μm) by a gravure printing method, and then left in an environment of 40 ° C. for 1 day. By doing so, the curing reaction proceeded with the drying of the composition to form a black colored layer 2 having a thickness of 3 μm after curing. Next, a surface of the base material layer 1 on the colored layer 2 side and a stainless steel foil (SUS304 (austenitic stainless steel foil) with a thickness of 20 μm) having been subjected to chemical conversion treatment on both sides were laminated by a dry laminating method. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) is applied to one surface of the stainless steel foil, and the adhesive layer 21 (thickness after curing 3 μm) is applied on the stainless steel foil 3. ) Was formed. Next, the adhesive layer 21 on the stainless steel foil 3 and the colored layer 2 on the base material layer 1 are pressure-heated and bonded, and then an aging treatment is performed to obtain the base material layer 1 / colored layer 2 / adhesion. A laminate of the agent layer 2 / stainless steel foil 3 was prepared. The chemical conversion treatment of the stainless steel foil is performed by a roll coating method on a treatment liquid consisting of a phenol resin, a chromium fluoride compound, and phosphoric acid so that the amount of chromium applied is 10 mg / m ² (dry weight). It was applied to both sides of the foil and baked under the condition that the film temperature was 180 ° C. or higher.

Next, a two-component olefin adhesive (a resin composition containing an acid-modified polypropylene resin and an epoxy resin, a thickness of 2 μm after curing) was applied to the stainless steel foil 3 side of the laminate and adhered onto the stainless steel foil 3. Layer 5 was formed. Further, an unstretched polypropylene film (CPP thickness 23 μm) as the thermosetting resin layer 4 was laminated on the adhesive layer 5. Next, the obtained laminate was heated and subjected to an aging treatment, and the base material layer 1 / colored layer 2 / adhesive layer 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were sequentially formed. An exterior material for a power storage device made of a laminated laminated film was obtained.

Example 2
Substrate layer 1 / colored layer 2 / adhesive layer in the same manner as in Example 1 except that the black colored layer 2 was formed using the colored layer forming composition having the composition B shown in Table 1. An exterior material for a power storage device was obtained, which consisted of a laminated film in which 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were laminated in this order.

Example 3
Substrate layer 1 / colored layer 2 / adhesive layer in the same manner as in Example 1 except that the black colored layer 2 was formed using the colored layer forming composition having the composition C shown in Table 1. An exterior material for a power storage device was obtained, which consisted of a laminated film in which 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were laminated in this order.

Example 4
Substrate layer 1 / colored layer 2 / adhesive layer in the same manner as in Example 1 except that the black colored layer 2 was formed using the colored layer forming composition having the composition D shown in Table 1. An exterior material for a power storage device was obtained, which consisted of a laminated film in which 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were laminated in this order.

Example 5
Substrate layer 1 / colored layer 2 / adhesive layer in the same manner as in Example 1 except that the black colored layer 2 was formed using the colored layer forming composition having the composition E shown in Table 1. An exterior material for a power storage device was obtained, which consisted of a laminated film in which 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were laminated in this order.

Example 6
Substrate layer 1 / colored layer 2 / adhesive layer in the same manner as in Example 1 except that the black colored layer 2 was formed using the colored layer forming composition having the composition F shown in Table 1. An exterior material for a power storage device was obtained, which consisted of a laminated film in which 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were laminated in this order.

Example 7
A stainless steel foil (SUS304 (austenite-based stainless steel foil)) in which a stretched nylon film (ONY thickness 15 μm) was used as the base material layer 1 and both sides were subjected to the same chemical conversion treatment as in Example 1 as the stainless steel foil 3. ) Substrate layer 1 / colored layer 2 / adhesive layer 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 in the same manner as in Example 1 except that a thickness of 40 μm) was used. Obtained an exterior material for a power storage device composed of laminated films in which

Example 8
A stainless steel foil (SUS304 (austenite-based)) in which a biaxially stretched polyethylene terephthalate film (PET thickness 4 μm) was used as the base material layer 1 and both sides were subjected to the same chemical conversion treatment as in Example 1 as the stainless steel foil 3. Stainless steel foil) Base material layer 1 / colored layer 2 / adhesive layer 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing property in the same manner as in Example 1 except that a thickness of 15 μm) was used. An exterior material for a power storage device made of a laminated film in which the resin layers 4 were laminated in order was obtained.

Example 9
Substrate layer 1 / colored layer 2 / adhesive layer 21 / stainless steel foil 3 in the same manner as in Example 1 except that a biaxially stretched polyethylene terephthalate film (PET thickness 9 μm) was used as the base material layer 1. An exterior material for a power storage device made of a laminated film in which the adhesive layer 5 / the thermosetting resin layer 4 was laminated in this order was obtained.

Example 10
Substrate layer 1 / colored layer 2 / adhesive layer 2 / stainless steel foil 3 in the same manner as in Example 1 except that a biaxially stretched polyethylene terephthalate film (PET thickness 9 μm) was used as the base material layer 1. Laminates were prepared. Next, the maleic anhydride-modified polypropylene as the adhesive layer 5 (thickness 14 μm) and the polypropylene as the thermosetting resin layer 4 (thickness 10 μm) are co-extruded onto the stainless steel foil 3 side of the laminate. Then, the adhesive layer 5 and the thermosetting resin layer 4 were formed on the stainless steel foil 3. Next, the obtained laminate was heated and subjected to an aging treatment, and the base material layer 1 / colored layer 2 / adhesive layer 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were sequentially formed. An exterior material for a power storage device made of a laminated laminated film was obtained.

Example 11
A stainless steel foil (SUS444 (ferritic stainless steel)) in which a biaxially stretched polyethylene terephthalate film (PET thickness 4 μm) was used as the base material layer 1 and both sides were subjected to the same chemical conversion treatment as in Example 1 as the stainless steel foil 3. Stainless steel foil) Base material layer 1 / colored layer 2 / adhesive layer 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing property in the same manner as in Example 1 except that a thickness of 15 μm) was used. An exterior material for a power storage device made of a laminated film in which the resin layers 4 were laminated in order was obtained.

Example 12
A stainless steel foil (SUS304 (austenite-based stainless steel foil)) in which a stretched nylon film (ONY thickness 25 μm) was used as the base material layer 1 and both sides were subjected to the same chemical conversion treatment as in Example 1 as the stainless steel foil 3. ) Substrate layer 1 / coloring in the same manner as in Example 1 except that an unstretched polypropylene film (CPP thickness 40 μm) was used as the heat-sealing resin layer 4 (thickness 40 μm) was used. An exterior material for a power storage device was obtained, which consisted of a laminated film in which layer 2 / adhesive layer 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were laminated in this order.

Comparative Example 1
Substrate layer 1 / colored layer 2 / adhesive layer in the same manner as in Example 1 except that the black colored layer 2 was formed using the colored layer forming composition having the composition G shown in Table 1. An exterior material for a power storage device was obtained, which consisted of a laminated film in which 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were laminated in this order.

Comparative Example 2
Substrate layer 1 / colored layer 2 / adhesive layer in the same manner as in Example 1 except that the black colored layer 2 was formed using the colored layer forming composition having the composition H shown in Table 1. An exterior material for a power storage device was obtained, which consisted of a laminated film in which 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were laminated in this order.

Comparative Example 3
Substrate layer 1 / colored layer 2 / adhesive layer in the same manner as in Example 1 except that the black colored layer 2 was formed using the colored layer forming composition having the composition I shown in Table 1. An exterior material for a power storage device was obtained, which consisted of a laminated film in which 21 / stainless steel foil 3 / adhesive layer 5 / heat-sealing resin layer 4 were laminated in this order.

Comparative Example 4
An aluminum foil (ALM thickness 25 μm JIS H4000) in which a stretched nylon film (ONY thickness 12 μm) was used as the base material layer 1 and both sides were subjected to the same chemical conversion treatment as in Example 1 instead of the stainless steel foil 3. : 2014 A8021P-O composition) was used, but in the same manner as in Example 10, the base material layer 1 / colored layer 2 / adhesive layer 21 / aluminum foil / adhesive layer 5 / heat fusion An exterior material for a power storage device made of a laminated film in which the sex resin layers 4 were laminated in order was obtained.

Comparative Example 5
An aluminum foil (ALM thickness 20 μm JIS H4000) in which a stretched nylon film (ONY thickness 15 μm) was used as the base material layer 1 and both sides were subjected to the same chemical conversion treatment as in Example 1 instead of the stainless steel foil 3. : 2014 A8021P-O composition) was used, but in the same manner as in Example 1, the base material layer 1 / colored layer 2 / adhesive layer 21 / aluminum foil / adhesive layer 5 / heat fusion An exterior material for a power storage device made of a laminated film in which the sex resin layers 4 were laminated in order was obtained.

Comparative Example 6
An aluminum foil (ALM thickness 20 μm JIS H4000) in which a stretched nylon film (ONY thickness 15 μm) was used as the base material layer 1 and both sides were subjected to chemical conversion treatment as in Example 1 instead of the stainless steel foil 3. : 2014 A8021P-O composition) was used, but in the same manner as in Example 10, the base material layer 1 / colored layer 2 / adhesive layer 21 / aluminum foil / adhesive layer 5 / heat fusion An exterior material for a power storage device made of a laminated film in which the sex resin layers 4 were laminated in order was obtained.

Reference example 1
An aluminum foil (ALM thickness 20 μm JIS H4000) in which a stretched nylon film (ONY thickness 15 μm) was used as the base material layer 1 and both sides were subjected to the same chemical conversion treatment as in Example 1 instead of the stainless steel foil 3. : A laminate of base material layer 1 / colored layer 2 / adhesive layer 2 / aluminum foil was prepared in the same manner as in Example 1 except that the composition of 2014 A8021PO was used. Next, the maleic anhydride-modified polypropylene as the adhesive layer 5 (thickness 20 μm) and the polypropylene as the thermosetting resin layer 4 (thickness 15 μm) are co-extruded onto the aluminum foil side of the laminate. , An adhesive layer 5 and a thermosetting resin layer 4 were formed on the aluminum foil. Next, the obtained laminate was heated and subjected to an aging treatment, and the base material layer 1 / colored layer 2 / adhesive layer 21 / aluminum foil / adhesive layer 5 / thermosetting resin layer 4 were laminated in this order. An exterior material for a power storage device made of a laminated film was obtained.

Reference example 2
An aluminum foil (ALM thickness 40 μm JIS H4000) using a stretched nylon film (ONY thickness 25 μm) as the base material layer 1 and performing the same chemical conversion treatment as in Example 1 instead of the stainless steel foil 3 : 2014 A8021P-O composition) was used, and an unstretched polypropylene film (CPP thickness 40 μm) was used as the heat-sealing resin layer 4 in the same manner as in Example 1. An exterior material for a power storage device made of a laminated film in which a base material layer 1 / a colored layer 2 / an adhesive layer 21 / an aluminum foil / an adhesive layer 5 / a heat-sealing resin layer 4 were laminated in this order was obtained.

[Delamination after high temperature and high humidity storage test]
Ten exterior materials for each power storage device obtained above were prepared and used as test samples. These test samples were allowed to stand in a high temperature and high humidity tester at 60 ° C. and 95% RH for 72 hours, then taken out and allowed to stand at room temperature for another 5 days. Next, the presence or absence of delamination (peeling) of the colored layer of the test sample was visually confirmed and evaluated according to the following evaluation criteria. The results are shown in Table 2.
A: 0 out of 10 test samples with the colored layer peeled off C: 1 or more test samples with the colored layer peeled off

[Measurement of bending stiffness]
The exterior material for each power storage device obtained above is cut into a rectangle having a width (direction perpendicular to the flow direction during film formation: TD) of 80 mm and a length (flow direction during film formation: MD) of 100 mm for testing. A sample was obtained. The bending stiffness (gf · cm ² / cm) of the obtained test sample was measured using a bending stiffness measuring machine (SMT / JTC-911BT). The measurement conditions were a curvature change rate of 0.1 / cm · sec, a clamp interval of 1 cm, a maximum curvature of 2.5 cm ^-1, and the average value of bending stiffness (rigid bending stiffness) for 10 test samples. The bending stiffness of the exterior material for each power storage device obtained above was used. The test sample was fixed to two clamps so that the edge having a width of 80 mm coincided with the direction of the clamp axis.
The evaluation criteria for bending stiffness are as follows. The results are shown in Table 2.
A: Bending stiffness 6.0 gf · cm ² / cm or less, 0.60 gf · cm ² / cm or more C: Bending stiffness 0.58 gf · cm less than ² / cm

[Measurement of piercing strength]
The exterior materials for each power storage device obtained above were cut into rectangles having a width of 80 mm and a length of 120 mm to obtain test samples. The piercing strength of the obtained test sample was measured from the base material layer side by a method according to JIS Z1707: 1997. Specifically, in a measurement environment of 23 ± 2 ° C. and relative humidity (50 ± 5)%, the test piece is fixed with a table having a diameter of 115 mm and a holding plate having an opening of 15 mm in the center, and the diameter is 1.0 mm. , A semicircular needle with a tip shape radius of 0.5 mm was pierced at a speed of 50 ± 5 mm per minute, and the maximum stress until the needle penetrated was measured. The number of test pieces was 5, and the average value was calculated. As the piercing strength measuring device, ZP-50N (force gauge) and MX2-500N (measurement stand) manufactured by Imada Co., Ltd. were used. The evaluation criteria for piercing strength are as follows. The results are shown in Table 2.
A: Puncture strength 60N or less, 25N or more B: Puncture strength 15N or more, less than 25N C: Puncture strength less than 15N

[Measurement of limit molding depth]
The exterior materials for each power storage device obtained above were cut into rectangles having a width (MD) of 90 mm and a length (TD) of 150 mm to obtain test samples. The MD of the exterior material for the power storage device corresponds to the rolling direction (RD) of the stainless steel foil or the aluminum alloy foil, and the TD of the exterior material for the power storage device corresponds to the TD of the stainless steel foil or the aluminum alloy foil. Next, in an environment of a temperature of 24 ° C. and a relative humidity of 50%, a female mold having a plane rectangular diameter of 31.6 mm (MD direction) × 54.5 mm (TD direction) and a corresponding male mold are used. Then, cold molding (pull-in one-stage molding) is performed by increasing the molding depth in 0.5 mm increments from a molding depth of 0.5 mm at a pressing pressure (surface pressure) of 0.25 MPa to obtain an exterior material for a power storage device. The molding depth 0.5 mm shallower than the molding depth when pinholes and cracks were generated was defined as the limit molding depth of the sample. To check for pinholes and cracks in the exterior material for power storage devices, shine light on the sample after cold molding with a penlight in a dark room and transmit the light to pinholes and cracks in the stainless steel foil or aluminum alloy foil. This was done by confirming whether or not the above occurred. In the molding, the male mold was arranged on the thermosetting resin layer side so that a concave portion was formed on the thermosetting resin layer side and a convex portion was formed on the base material layer side. The clearance between the male type and the female type was 0.3 mm. The surface of the female mold has a maximum height roughness (nominal value of Rz) of 3.2 μm specified in Table 2 of the comparative surface roughness standard piece in JIS B 0659-1: 2002 Annex 1 (reference). Is. The male surface has a maximum height roughness (nominal value of Rz) of 3.2 μm specified in Table 2 of the comparative surface roughness standard piece in JIS B 0659-1: 2002 Annex 1 (reference). , Corner R2.0 mm, ridgeline R1.0 mm. The evaluation criteria for moldability are as follows. The results are shown in Table 2.
A: Limit molding depth 3.0 mm or more B: Limit molding depth 2.0 mm or more and 2.5 mm or less C: Limit molding depth 1.5 mm or less

[Evaluation of wrinkle formation due to tape peeling]
In an environment of a temperature of 24 ° C. and a relative humidity of 50%, a female mold and a male mold were used, and the exterior material 10 for each power storage device obtained above was molded with a pressing pressure of 0.9 MPa to obtain the following battery sizes 1, Two recesses were formed. In molding, the male mold is arranged on the thermosetting resin layer 4 side, and the molded portion is formed so that a concave portion is formed on the thermosetting resin layer 4 side and a convex portion is formed on the base material layer 1 side. Provided. The clearance between the male type and the female type was 0.3 mm. The surface of the female mold has a maximum height roughness (nominal value of Rz) of 3.2 μm specified in Table 2 of the comparative surface roughness standard piece in JIS B 0659-1: 2002 Annex 1 (reference). Is. The male surface has a maximum height roughness (nominal value of Rz) of 1.6 μm specified in Table 2 of the comparative surface roughness standard piece in JIS B 0659-1: 2002 Annex 1 (reference). ..
Battery size 1: Recess width 30 mm, length 90 mm, molding depth 3 mm
Battery size 2: Recess width 94 mm, length 128 mm, molding depth 3 mm
In Examples 8 and 11 in which the moldability evaluation was evaluation B, the molding depths of the battery size 1 and the battery size 2 were set to 2 mm, respectively.

Next, as shown in the schematic view of FIG. 5, an acrylic plate 22 having a width of 27 mm, a length of 87 mm, and a height of 3 mm is inserted into the recess of the battery size 1, and the recess of the battery size 2 has a width of 91 mm. An acrylic plate 22 having a length of 125 mm and a height of 3 mm (corresponding to the direction of the molding depth) was inserted. The inserted acrylic plate 22 was fixed with double-sided tape NO751B manufactured by Teraoka Seisakusho Co., Ltd. so as to be in close contact with the bottom of the recess of the exterior material 10 for the power storage device. Next, on the surface 10a on the convex side of the molded portion of the exterior material for the power storage device, a double-sided tape 31 (# 610 manufactured by 3M, thickness 120 μm) having a width of 5 mm and a length of 50 mm and an aluminum foil 41 (thickness 120 μm) as adhesive tapes 35 μm) was laminated, and the double-sided tape 31 was attached to the surface 10a on the convex side of the molded portion of the exterior material 10 for the power storage device by reciprocating once from the top of the aluminum foil 41 with a 200 g rubber roller. Next, pinch the end of the double-sided tape that is not attached to the convex portion of the molded portion with a finger, pull the double-sided tape 31 together with the aluminum foil 41 in the 180 ° direction (direction of the arrow in FIG. 5), and the convex portion of the molded portion. It was peeled off from the surface 10a of. Next, the surface of the molded portion from which the double-sided tape 31 was peeled off was visually observed, and the formation of wrinkles due to the tape peeling was evaluated according to the following criteria. The evaluation results are shown in Table 2.
A: Since the molded portion did not follow the tape, no wrinkles were formed on the surface, and the tape was appropriately peeled off from the surface of the exterior material for the power storage device.
C: The molded portion follows the tape, and wrinkles are formed on the surface.

In Table 2, ONY is a stretched nylon film, PET is a polyethylene terephthalate film, SUS is a stainless steel foil, ALM is an aluminum foil, UR is a cured product of a two-component urethane adhesive, and OE is a cured product of a polyolefin resin and an epoxy resin. A product, CPP means unstretched polypropylene film, PPa means polypropylene anhydride, and PP means polypropylene. Further, the numerical value described after the layer means the thickness (μm) of the layer, and for example, “ONY10” means “a stretched nylon film having a thickness of 10 μm”.

As is clear from the results shown in Table 2, the exterior materials for power storage devices of Examples 1 to 12 are laminated with a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer in this order. It is composed of a body, and the colored layer is a cured product of a composition containing carbon black, diamine, polyol, and a curing agent, and further, the content of the curing agent in the colored layer is carbon black, diamine, and polyol. It is set to 2 parts by mass or more and 20 parts by mass or less with respect to a total of 100 parts by mass. In the exterior materials for power storage devices of Examples 1 to 12, even when the exterior materials for power storage devices are used in a high temperature and high humidity environment, peeling of the colored layer containing carbon black is suppressed, and further. It has high rigidity, and wrinkles are unlikely to be formed when the tape is peeled off.

As described above, the present disclosure provides the inventions of the following aspects.
Item 1. It is composed of a laminate including at least a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer in this order.
The colored layer is a cured product of a composition containing carbon black, diamine, polyol, and a curing agent.
The exterior material for a power storage device, wherein the content of the curing agent in the colored layer is 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass in total of the carbon black, the diamine, and the polyol.
Item 2. In the colored layer
The content of the carbon black is 15% by mass or more and 60% by mass or less.
Item 2. The exterior material for a power storage device according to Item 1, wherein the total content of the carbon black, the diamine, and the polyol is 40% by mass or more and 85% by mass or less.
Item 3. Item 2. The exterior material for a power storage device according to Item 1 or 2, wherein the polyol is at least one selected from the group consisting of polyurethane-based polyols, polyester-based polyols, and polyether-based polyols.
Item 4. Item 6. The item according to any one of Items 1 to 3, wherein the diamine is at least one selected from the group consisting of ethylenediamine, dimerdiamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, and dicyclohexylmethanediamine. Exterior material for power storage devices.
Item 5. Item 2. The exterior material for a power storage device according to any one of Items 1 to 4, wherein the curing agent is an isocyanate compound.
Item 6. Item 2. The exterior material for a power storage device according to any one of Items 1 to 5, further comprising a surface coating layer on the side of the base material layer opposite to the colored layer side.
Item 7. The thickness of the laminate is 45 μm or more and 120 μm or less.
The thickness of the stainless steel foil is 15 μm or more and 40 μm or less.
Item 2. The exterior material for a power storage device according to any one of Items 1 to 6, wherein the laminated body has a bending stiffness of 0.60 gf · cm ² / cm or more and 6.0 gf · cm ² / cm or less.
Item 8. Item 2. The exterior material for a power storage device according to any one of Items 1 to 7, which has an adhesive layer between the base material layer and the stainless steel foil.
Item 9. Item 2. The exterior material for a power storage device according to any one of Items 1 to 8, which has an adhesive layer between the stainless steel foil and the thermosetting resin layer.
Item 10. At least, it includes a step of obtaining a laminate including a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer in this order.
The colored layer is a cured product of a composition containing carbon black, diamine, polyol, and a curing agent.
A method for producing an exterior material for a power storage device, wherein the content of the curing agent in the colored layer is 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass in total of the carbon black, the diamine, and the polyol. ..
Item 11. 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 9.

1 Base material layer 2 Colored layer 21 Adhesive layer 3 Stainless steel foil 4 Thermosetting resin layer 5 Adhesive layer 6 Surface coating layer 10 ... Exterior material for power storage device 10a ... Convex side of molded portion of exterior material for power storage device Surface 20 ... Double-sided adhesive tape 22 ... Acrylic plate 31 ... Double-sided tape 41 ... Aluminum foil

Claims (11)

It is composed of a laminate including at least a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer in this order.
The colored layer is a cured product of a composition containing carbon black, diamine, polyol, and a curing agent.
The exterior material for a power storage device, wherein the content of the curing agent in the colored layer is 2 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass in total of the carbon black, the diamine, and the polyol. In the colored layer
The content of the carbon black is 15% by mass or more and 60% by mass or less.
The exterior material for a power storage device according to claim 1, wherein the total content of the carbon black, the diamine, and the polyol is 40% by mass or more and 85% by mass or less. The exterior material for a power storage device according to claim 1 or 2, wherein the polyol is at least one selected from the group consisting of polyurethane-based polyols, polyester-based polyols, and polyether-based polyols. The diamine according to any one of claims 1 to 3, wherein the diamine is at least one selected from the group consisting of ethylenediamine, dimerdiamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, and dicyclohexylmethanediamine. The exterior material for the power storage device described. The exterior material for a power storage device according to any one of claims 1 to 4, wherein the curing agent is an isocyanate compound. The exterior material for a power storage device according to any one of claims 1 to 5, further comprising a surface coating layer on the side of the base material layer opposite to the colored layer side. The thickness of the laminate is 45 μm or more and 120 μm or less.
The thickness of the stainless steel foil is 15 μm or more and 40 μm or less.
The exterior material for a power storage device according to any one of claims 1 to 6, wherein the laminated body has a bending stiffness of 0.60 gf · cm ² / cm or more and 6.0 gf · cm ² / cm or less. The exterior material for a power storage device according to any one of claims 1 to 7, which has an adhesive layer between the base material layer and the stainless steel foil. The exterior material for a power storage device according to any one of claims 1 to 8, which has an adhesive layer between the stainless steel foil and the thermosetting resin layer. A step of obtaining a laminate having at least a base material layer, a colored layer, a stainless steel foil, and a thermosetting resin layer in this order is provided.
The colored layer is a cured product of a composition containing carbon black, diamine, polyol, and a curing agent.
A method for producing an exterior material for a power storage device, wherein the content of the curing agent in the colored layer is 2 parts by mass or more and 20 parts by mass or less with respect to a total of 100 parts by mass of the carbon black, the diamine, and the polyol. .. 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 9.