Exterior material for power storage device, exterior case for power storage device, and power storage device

Abstract

To provide an exterior material for a power storage device having an outer surface that has high adhesion to an attachment tape, an exterior case formed from the exterior material, and a power storage device packaged with the exterior material.SOLUTION: An exterior material 1 for a power storage device is formed by laminating, in this order from the outside to the inside, at least a substrate protective layer 2, a substrate layer 3, a barrier layer 4, and a sealant layer 5. The substrate protective layer 2 is made of a resin composition containing a lubricant and a resin. The adhesion strength between the substrate protective layer 2 and the substrate layer 3 is 3.0 N / 15 mm or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an exterior material for a power storage device, an exterior case for a power storage device, and a power storage device.

Background Art

[0002] In power storage devices used in mobile devices such as smartphones and tablets, hybrid vehicles, electric vehicles, power storage devices used for wind power generation, solar power generation, and power storage of nighttime electricity, etc., the power storage device main body is covered with an exterior material.

[0003] Generally, the exterior material is composed of a sheet-like laminate in which at least a base material layer, a barrier layer, and a sealant layer are laminated in order from the outside to the inside. Further, a base material protective layer for protecting the base material layer is laminated on the outside of the base material layer. The base material protective layer is made of a resin composition, and the resin composition contains a lubricant for imparting slipperiness to the base material protective layer and improving the moldability of the exterior material (see, for example, Patent Documents 1-3).

[0004] In the manufacturing process of a power storage device using an exterior material, a recess is formed in a part of the exterior material by a predetermined molding process (e.g., deep drawing molding process, protruding molding process). The power storage device main body is housed and incorporated into the recess of the exterior material (specifically, the recess of the exterior material), and an electrolyte such as an electrolytic solution is filled (injected) into the exterior material from the opening of the exterior material. Then, the opening end of the exterior material is heat-sealed, so that the power storage device main body is covered with the exterior material in a state of being surrounded by the exterior material (see, for example, Patent Documents 4 and 5). Next, predetermined characters (including symbols) such as product management numbers, predetermined codes (e.g., barcodes, two-dimensional codes), etc. are printed on the outer surface of the exterior material as information related to the manufactured power storage device, and the power storage device is manufactured.

[0005] Before filling the electrolyte into the exterior material in the manufacturing process of the above-described power storage device, a protective tape for protecting the outer surface of the exterior material is attached to the outer surface of the exterior material to prevent scratches (e.g., abrasions) on the outer surface of the exterior material and corrosion of the outer surface of the exterior material by the electrolyte. Then, this protective tape is peeled off from the outer surface of the exterior material after filling the electrolyte into the exterior material and before printing on the outer surface of the exterior material, so as to ensure that good printing on the outer surface of the exterior material is not hindered by the protective tape.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0007] By the way, in the power storage device obtained through the manufacturing process of the above-described power storage device, an attachment tape for attaching the power storage device to its attachment location is attached to the outer surface of the exterior material, and the power storage device is fixedly attached to the attachment location by the attachment tape. At this time, in order to be able to firmly attach the power storage device to the attachment location, it is desirable that the outer surface of the exterior material has high adhesion to the attachment tape.

[0008] The present invention has been made in view of the above-described technical background, and an object of the present invention is to provide an exterior material for a power storage device having an outer surface with high adhesion to an attachment tape, an exterior case formed of the exterior material, and a power storage device exteriorly packaged with the exterior material.

Means for Solving the Problem

[0009] The present invention provides the following means.

[0010] 1) An exterior material for a power storage device in which at least a base material protective layer, a base material layer, a barrier layer, and a sealant layer are laminated in order from the outside to the inside, wherein the base material protective layer is made of a resin composition containing a lubricant and a resin, and the exterior material for a power storage device has an adhesion strength between the base material protective layer and the base material layer of 3.0 N / 15 mm or less.

[0011] 2) The exterior material for a power storage device according to item 1 above, wherein the resin contained in the base material protective layer contains a polyamide-imide resin not containing a curing agent.

[0012] 3) The exterior material for a power storage device according to item 1 or 2 above, wherein the base material layer contains a polyamide film and the outer surface of the polyamide film is not corona-treated.

[0013] 4) The exterior material for a power storage device according to any one of items 1 to 3 above, wherein the glass transition point of the resin contained in the base material protective layer is 220°C or higher.

[0014] 5) An exterior case for a power storage device in which a recess for accommodating a power storage device body is formed by deep drawing or protrusion forming in the exterior material for a power storage device according to any one of items 1 to 4 above.

[0015] 6) A power storage device in which a power storage device body is exteriorly packaged with the exterior material for a power storage device according to any one of items 1 to 4 above.

[0016] 7) A method for manufacturing a power storage device, comprising preparing an exterior material in which at least a base material protective layer, a base material layer, a barrier layer, and a sealant layer are laminated in order from the outside to the inside, attaching a protective tape to the outer surface of the exterior material, and then peeling the protective tape from the outer surface of the exterior material to peel the base material protective layer integrally with the protective tape from the base material layer.

Advantages of the Invention

[0017] The present invention has the following effects.

[0018] In the above item 1, since the adhesion strength between the base material protective layer and the base material layer is 3.0 N / 15 mm or less, when the protective tape attached to the outer surface of the exterior material is peeled off from the outer surface of the exterior material, the base material protective layer containing the lubricant is also peeled off from the base material layer integrally with the protective tape. As a result, the outer surface of the exterior material has high adhesion to the mounting tape, and thus the mounting tape can be firmly adhered to the outer surface of the exterior material. Furthermore, the outer surface of the exterior material has high printing adhesion.

[0019] In the above item 2, since the resin contained in the base material protective layer contains a polyamide-imide resin not containing a curing agent, the base material protective layer has flexibility. Therefore, it is possible to suppress the occurrence of damage such as cracks caused by high temperature and pressing force during heat sealing, and it is easy to adjust the adhesion strength between the base material protective layer and the base material layer to a desired value.

[0020] In the above item 3, since the base material layer contains a polyamide film and the outer surface of the polyamide film is not corona-treated, it is easy to adjust the adhesion strength between the base material protective layer and the base material layer to a desired value.

[0021] In the above item 4, since the glass transition point of the resin contained in the base material protective layer is 220°C or higher, it is possible to suppress the adhesion of the exterior material to the seal bar during heat sealing.

[0022] In the above item 5, it is possible to provide an exterior case for a power storage device having an outer surface with high adhesion to the mounting tape.

[0023] In the above item 6, it is possible to provide a power storage device having an outer surface with high adhesion to the mounting tape.

[0024] In the above item 7, since the base material protective layer is peeled off from the base material layer integrally with the protective tape by peeling the protective tape from the outer surface of the exterior material, when attaching the power storage device to the attachment location, the attachment tape can be firmly adhered to the outer surface of the exterior material, and the printing adhesion of the outer surface of the exterior material can be improved.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0026] An embodiment of the present invention will be described below with reference to the drawings.

[0027] As shown in FIG. 1, an exterior material 1 for a power storage device according to an embodiment of the present invention has an inner surface 1a and an outer surface 1b, and is composed of a sheet-like laminate in which a base material protective layer 2, a base material layer 3, a barrier layer 4, and a sealant layer 5 are laminated in order from the outside to the inside. In the present embodiment, the barrier layer 4 is composed of a metal foil layer, and the sealant layer 5 is composed of a heat-sealable resin layer and is located in the innermost layer of the exterior material 1.

[0028] The base material layer 3 is bonded to the outer surface of the barrier layer 4 via the outer adhesive layer 6. The base material protective layer 2 is laminated on the outside of the base material layer 3, and more specifically, it is laminated on the outer surface of the base material layer 3. The sealant layer 5 is bonded to the inner surface of the barrier layer 4 via the inner adhesive layer 7.

[0029] As shown in FIG. 2, the exterior material 1 is used for the exterior of a battery 50 such as a lithium-ion secondary battery as a power storage device.

[0030] The battery 50 (power storage device) includes a battery body 51 as a power storage device body, and is externally packaged by sealing the battery body 51 in an exterior case 20 formed of the exterior material 1.

[0031] That is, the exterior material 1 is processed into an exterior case body 21 in which a recess 22 for accommodating the battery body 51 is formed, and a flat exterior lid body 25.

[0032] In the exterior case body 21, a flange portion 23 is integrally provided so as to protrude outward around the recess 22. The exterior case body 21 and the exterior lid body 25 are arranged such that the inner surface 1a of the exterior case body 21 and the inner surface 1a of the exterior lid body 25 face each other, and with the battery body 51 accommodated in the recess 22 of the exterior case body 21, the flange portion 23 of the exterior case body 21 and the outer peripheral portion 26 of the exterior lid body 25 are overlapped with each other, and the flange portion 23 and the outer peripheral portion 26 are heat-sealed. More specifically, the sealant layer 5 of the flange portion 23 and the sealant layer 5 of the outer peripheral portion 26 are heat-fused. The symbol "HS" in the figure is the heat-sealing portion (heat-fusing portion) between the flange portion 23 and the outer peripheral portion 26.

[0033] The exterior case body 21 is made of a deep drawing processed product or a protrusion formed processed product. That is, in the exterior case body 21, the recess 22 is formed in the exterior material 1 by deep drawing processing or protrusion forming processing such that the inner surface 1a of the exterior material 1 faces the inside of the recess 22.

[0034] Next, an example of a method for manufacturing a battery (power storage device) 50 using the exterior material 1 of the present embodiment will be described below.

[0035] As shown in FIG. 3, the manufacturing method of the battery 50 according to the present embodiment includes a step of preparing the exterior material 1 (exterior material 1 preparation step) S1, a step of forming a concave portion 22 in a part of the exterior material 1 by a predetermined forming process (forming process step) S2, a step of accommodating and incorporating the battery body 51 into the concave portion 22 of the exterior material 1 (battery body 51 incorporation step) S3, a first heat sealing step (first heat sealing step) S4 for the exterior material 1, a step of attaching a protective tape (indicated by cross hatching) 10 to the outer surface 1b of the exterior material 1 (protective tape 10 attachment step) S5, a step of injecting (filling) an electrolytic solution 17 as an electrolyte into the exterior material 1 (specifically, the concave portion 22 of the exterior material 1) (electrolytic solution 17 injection step) S6, a second heat sealing step (second heat sealing step) S7 for the exterior material 1, a step of peeling the protective tape 10 from the outer surface 1b of the exterior material 1 (protective tape 10 peeling step) S8, a third heat sealing step (third heat sealing step) S9 for the exterior material 1, and a step of printing on the outer surface 1b of the exterior material 1 (printing step) S10. These steps are performed in the order described.

[0036] In the exterior material 1 preparation step S1, the exterior material 1 of the present embodiment is prepared. The prepared exterior material 1 is cut into a predetermined shape (e.g., square shape) in plan view, and as shown in FIG. 4(a), a base material protective layer 2, a base material layer 3, an outer adhesive layer 6, a barrier layer 4, an inner adhesive layer 7, and a sealant layer 5 are laminated in order from the outside to the inside of the exterior material 1.

[0037] In the forming process step S2, the concave portion 22 is formed in a predetermined part of the exterior material 1 by a deep drawing process or a bulging process according to a conventional method.

[0038] In the incorporation step S3 of the battery body 51, the battery body 51 is accommodated and incorporated into the recess 22 of the exterior material 1. Two tab leads 53 are provided so as to protrude from the battery body 51. Then, the half part of the exterior material 1 (the lower half part of the exterior material 1 in the figure) is bent from the fold line (indicated by a two-dot chain line) 16 toward the recess 22 (battery body 51) side so that the exterior material 1 becomes double-folded.

[0039] In the first heat-sealing step S4, one of the left and right side edges 1d of the double-folded exterior material 1 is heat-sealed together, and the edge portions 1e of the exterior material 1 are heat-sealed together. The dot-hatching portion HS in the figure is the heat-sealing portion HS (the same hereinafter) of the exterior material 1.

[0040] As shown in FIGS. 5 and 6, the heat-sealing of the side edges 1d of the exterior material 1 is performed by sandwiching the side edges 1d between a pair of seal bars 61, 62 heated to a predetermined seal temperature. The heat-sealing of the edge portions 1e of the exterior material 1 is also performed in the same manner, and further, the heat-sealing of other portions of the exterior material 1 described later is also performed in the same manner.

[0041] In the step S5 of attaching the protective tape 10, the protective tape 10 is attached to the outer surface 1b of the exterior material 1 so as to cover substantially the whole of it. As a result, as shown in FIG. 4(b), the protective tape 10 is laminated on the outer side of the base material protective layer 2 (specifically, the outer surface of the base material protective layer 2) of the exterior material 1.

[0042] The protective tape 10 is for protecting the outer surface 1b of the exterior material 1 from scratches (e.g., abrasions) on the outer surface 1b of the exterior material 1 and corrosion of the outer surface 1b of the exterior material 1 by the electrolytic solution (electrolyte) between the end of the step S5 of attaching the protective tape 10 and the start of the step S8 of peeling the protective tape 10.

[0043] The protective tape 10 is composed of a single-sided adhesive tape, that is, an adhesive layer (not shown) is formed on the adhesive surface 10a which is formed on one side of the support of the protective tape 10. The type of the support of the protective tape 10 is not limited, and as the support, a resin film having electrolyte resistance or the like is used. Specifically, a polyethylene terephthalate film, a polypropylene film, a polyethylene film or the like is used.

[0044] In the step S6 of injecting the electrolyte 17, the electrolyte 17 is injected into the recess 22 from the gap between the other side edge portions 1f of the exterior member 1 using an electrolyte injection device (not shown) according to a conventional method.

[0045] In the second heat-sealing step S7, the other side edge portions 1f of the exterior member 1 are heat-sealed to seal the gap between the side edge portions 1f. Then, the battery body 51 is left at room temperature or / and in a heating environment for a predetermined period (e.g., for several days) in order to sufficiently immerse the electrolyte 17 in the battery body 51 or reduce the viscosity of the electrolyte. Next, an initial charge of the battery body 51 and a degassing process for the battery body 51 are performed. The off-gas released from the battery body 51 by the degassing process is stored in a portion 18 between the recess 22 and the side edge portion 1f of the exterior member 1 (this portion 18 is hereinafter referred to as the "off-gas reservoir portion 18" of the exterior member 1).

[0046] In the peeling step S8 of the protective tape 10, as shown in FIG. 4(c), by performing an operation of peeling the protective tape 10 from the outer surface of the exterior member 1, the substrate protective layer 2 is integrally peeled from the substrate layer 3 (specifically, the outer surface of the substrate layer 3) together with the protective tape 10. Thereby, the substrate layer 3 of the exterior member 1 is located on the outermost layer of the exterior member 1 and the outer surface of the substrate layer 3 becomes the outer surface 1b of the exterior member 1. Then, a gas vent hole (not shown) is opened in the off-gas reservoir portion 18 of the exterior member 1 to allow the off-gas accumulated in the off-gas reservoir portion 18 to escape to the outside of the exterior member 1 through the gas vent hole.

[0047] In the third heat sealing step S9, a portion 1g between the recess 22 and the gas outlet reservoir 18 in the exterior material 1 is heat sealed, and the side of the exterior material 1 on the gas outlet reservoir 18 side is trimmed to cut off the gas outlet reservoir 18 from the exterior material 1.

[0048] In the printing step S10, on the outer surface 1b of the exterior material 1, predetermined characters (including symbols), predetermined codes (e.g., barcodes, two-dimensional codes), etc., such as product management numbers and manufacturing dates and times, are printed as information related to the manufactured battery 50 by a printing device such as a printer (e.g., an inkjet printer).

[0049] The battery 50 manufactured through the above steps is attached to the installation location by attaching an attachment tape (not shown) to the outer surface 1b of the exterior material 1 when attaching the battery 50 to the installation location.

[0050] Next, the configuration of the exterior material 1 will be described in detail below.

[0051] (Base material protective layer 2) As shown in FIG. 1, the base material protective layer 2 is a layer that protects the base material layer 3 and is disposed outside the base material layer 3. Specifically, the base material protective layer 2 is disposed as the outermost layer of the exterior material 1 and is the layer that contacts the seal bars 61 and 62 during the first heat sealing step S4 (see FIG. 6).

[0052] Furthermore, the base material protective layer 2 is made of a resin composition containing a lubricant and a resin. Specifically, it is composed of a coat layer of a resin composition containing a lubricant and a resin.

[0053] The glass transition point (Tg) of the resin contained in the base material protective layer 2 is not limited, and preferably it is 220°C or higher. In this case, adhesion of the exterior material 1 to the seal bar 61 (62) during heat sealing can be suppressed.

[0054] The glass transition temperature (Tg) is the temperature at which the molecular chains of the resin particles start Brownian motion, and is indicated by the onset temperature (onset point) of endotherm by differential scanning calorimetry (DSC) analysis based on JIS (Japanese Industrial Standards) K7121:1987 "Method for Measuring Transition Temperature of Plastics". The higher the glass transition temperature, the higher the heat resistance. Even if the seal temperature and / or seal pressing force of heat sealing increase, it becomes difficult for the resin to adhere to the seal bar 61(62), and seal failure is less likely to occur. Therefore, since the glass transition temperature of the resin contained in the base material protective layer 2 is 220°C or higher, the heat resistance of the base material protective layer 2 is high, and thus the above effects can be surely obtained.

[0055] Also, in the base material protective layer 2, since the resin composition contains a lubricant, high moldability can be obtained even if the resin has a high glass transition temperature.

[0056] As the resin having a glass transition temperature of 220°C or higher, it is preferable to use polyamideimide resin (glass transition temperature: 250°C to 355°C), polyethersulfone (glass transition temperature: 225°C to 230°C), etc.

[0057] When the resin is polyamideimide resin, it is particularly preferable to use a polyamideimide resin having a glass transition temperature in the range of 250°C to 350°C, and more preferably a polyamideimide resin in the range of 250°C to 320°C.

[0058] In the coating liquid of the resin composition containing a lubricant and a resin for forming the base material protective layer 2 (this coating liquid is also referred to as "coating liquid for forming base material protective layer" for convenience of explanation), the content of the resin such as polyamideimide resin is not limited, and preferably it is in the range of 1 mass% to 30 mass%.

[0059] Also, the resin amount in the base material protective layer 2 is not limited, and preferably it is in the range of 0.1 g / m 2 ~5 g / m 2 It is preferably in this range. The resin amount means the net resin amount excluding the lubricant and the solvent. When the resin amount is 0.1 g / m 2By being as described above, the heat resistance can be surely improved. When the resin amount is 5 g / m 2 or less, by this, the decrease in the moldability of the exterior material 1 due to the resin amount being too large can be surely suppressed. A particularly preferable lower limit of the resin amount is 0.2 g / m 2 and a particularly preferable upper limit is 3 g / m 2 .

[0060] The lubricant is for imparting slipperiness to the base material protective layer 2 to enhance the moldability of the exterior material 1. Since the base material protective layer 2 contains the lubricant, the exterior material 1 can be favorably molded in the molding process S2.

[0061] The type of the lubricant is not limited. As the lubricant, a fatty acid amide-based lubricant is preferably used. Specifically, unsaturated fatty acid bisamide, N-substituted amide, saturated fatty acid amide, unsaturated fatty acid amide, saturated fatty acid bisamide, etc. can be used, and one of these or two or more of these can be used. These lubricants precipitate on the outer surface of the base material protective layer 2, that is, the outer surface 1b of the exterior material 1, impart slipperiness to the outer surface 1b, and improve the moldability of the exterior material 1.

[0062] Examples of the unsaturated fatty acid bisamide include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, and N,N'-dioleyl sebacic acid amide.

[0063] Examples of the N-substituted amide include N-oleyl palmitic acid amide (NOPA), N-stearyl stearic acid amide (NSSA), N-stearyl oleic acid amide (NSOA), N-oleyl stearic acid amide (NOSA), and N-stearyl erucic acid amide (NSEA).

[0064] Examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide.

[0065] Examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide.

[0066] Examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, and N,N'-distearyl sebacic acid amide.

[0067] Among the above-mentioned lubricants, at least one lubricant selected from the group consisting of unsaturated fatty acid bisamides and N-substituted amides can be recommended. The reason is that these lubricants have a structure in which the amide group is sandwiched between aliphatic hydrocarbons and are difficult to be trapped by the polyamideimide resin. Therefore, better lubricity can be obtained than other lubricants at the same addition amount, and the molding processability of the exterior material 1 can be further improved.

[0068] The content of the lubricant in the base material protective layer 2, that is, the ratio of the lubricant to the total amount of the resin and the lubricant, is preferably in the range of 1% by mass to 20% by mass. When the content of the lubricant is 1% by mass or more, good lubricity can be surely imparted to the base material protective layer 2. When the content of the lubricant is 20% by mass or less, the amount of bleed-out of the lubricant from the outer surface 1b of the exterior material 1 can be surely reduced. The particularly preferred lower limit of the content of the lubricant is 2% by mass, and the particularly preferred upper limit is 10% by mass.

[0069] (Base material layer 3) The base material layer 3 is preferably made of a heat-resistant resin film that does not melt at the heat fusion temperature (sealing temperature) when heat-sealing the heat-sealing planned part of the exterior material 1. The heat-resistant resin preferably has a melting point that is 10°C or more, preferably 20°C or more higher than the melting point of the resin forming the sealant layer 5. Examples of heat-resistant resin films that satisfy this condition include polyamide films (e.g., nylon films), polyester films, etc., and in particular, their stretched films are preferably used. Among them, as the base material layer 3, it is particularly preferable to use at least one of a biaxially stretched polyamide film (e.g., biaxially stretched nylon film), a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate (PET) film, and a biaxially stretched polyethylene naphthalate (PEN) film. The type of nylon film is not limited, and as the nylon film, 6-nylon film, 6,6-nylon film, MXD-nylon film, etc. are used.

[0070] Also, the base material layer 3 may be formed as a single layer or as a multi-layer. When the base material layer 3 is formed as a multi-layer, examples of its structure include a polyester film / polyamide film (e.g., PET film / nylon film), etc.

[0071] The thickness of the base material layer 3 is not limited, and preferably it is in the range of 9 μm to 50 μm. In this case, the exterior material 1 can ensure sufficient strength, and can surely reduce the processing stress acting on the exterior material 1 during forming processes such as deep drawing forming and flanging forming, and can surely improve the formability of the exterior material 1. The particularly preferable lower limit of the thickness of the base material layer 3 is 12 μm, and the particularly preferable upper limit is 30 μm. When the base material layer 3 is formed as a multi-layer, the total thickness of the multi-layer is preferably the above-mentioned preferable thickness, and the thickness of the adhesive for bonding a plurality of layers is also included in the above-mentioned thickness.

[0072] (Adhesion strength between the base material protective layer 2 and the base material layer 3) The adhesion strength between the base material protective layer 2 and the base material layer 3 is preferably 3.0 N / 15 mm or less. In this case, in the peeling step S8 of the protective tape 10, when the protective tape 10 is peeled from the outer surface 1b of the exterior material 1, the base material protective layer 2 is also reliably peeled from the base material layer 3 integrally with the protective tape 10. As a result, the outermost layer of the exterior material 1 becomes the base material layer 3 instead of the base material protective layer 2 (see Fig. 4(c)).

[0073] Here, when comparing the adhesion between the outer surface 1b of the exterior material 1 and the mounting tape when the outermost layer of the exterior material 1 is the base material protective layer 2 with the adhesion between the outer surface 1b of the exterior material 1 and the mounting tape when the outermost layer of the exterior material 1 is the base material layer 3, since the base material protective layer 2 contains a lubricant, the adhesion between the outer surface 1b of the exterior material 1 and the mounting tape is higher in the latter case than in the former case.

[0074] Therefore, since the outermost layer of the exterior material 1 is the base material layer 3, when attaching the battery 50 to the attachment location, the mounting tape can be firmly adhered to the outer surface 1b of the exterior material 1, and thus the battery 50 can be firmly attached to the attachment location.

[0075] Also, when comparing the printing adhesion of the outer surface 1b of the exterior material 1 when the outermost layer of the exterior material 1 is the base material protective layer 2 with the printing adhesion of the outer surface 1b of the exterior material 1 when the outermost layer of the exterior material 1 is the base material layer 3, since the base material protective layer 2 contains a lubricant, the printing adhesion of the outer surface 1b of the exterior material 1 is higher in the latter case than in the former case.

[0076] Therefore, since the outermost layer of the exterior material 1 is the base material layer 3, the outer surface 1b of the exterior material 1 has high printing adhesion.

[0077] More preferably, the adhesion strength between the base material protective layer 2 and the base material layer 3 is 2.5 N / 15 mm or less. The lower limit of the adhesion strength between the base material protective layer 2 and the base material layer 3 is not limited, and is preferably 0.1 N / 15 mm.

[0078] The resin contained in the base material protective layer 2 is preferably a polyamide-imide resin without a curing agent. In this case, it is possible to reliably suppress the adhesion of the exterior material 1 to the seal bar 61 (62) during heat sealing. Further, since the polyamide-imide resin does not contain a curing agent, the base material protective layer 2 has flexibility, and it is possible to suppress the occurrence of damage such as cracks caused by high temperature and pressing force during heat sealing, and it is easy to adjust the adhesion strength between the base material protective layer 2 and the base material layer 3 to a desired value.

[0079] An example of a method for forming the base material protective layer 2 using a polyamide-imide resin without a curing agent is as follows.

[0080] The polyamide-imide resin is dissolved in a solvent to adjust the viscosity of the polyamide-imide resin solution, and a predetermined amount of a lubricant is added to and dispersed in this resin solution to prepare a coating solution. Then, this coating solution is applied in a layer of a predetermined thickness on the outer surface of the base material layer 3, and the solvent in the coating solution is evaporated by drying the coating solution, thereby forming the base material protective layer (coating layer) 2 composed of a cured layer of the coating solution.

[0081] As the solvent for the polyamide-imide resin, N-methyl-2-pyrrolidone (NMP), xylene, methyl ethyl ketone, ethanol, toluene, γ-butyrolactone, 1,3-dimethyl-2-imidazolidinone, etc. can be used.

[0082] The coating method of the coating solution is not limited, and preferably, as the coating method, a roll coating method such as a gravure roll coating method or a reverse roll coating method is used.

[0083] The coating amount of the coating solution is not limited, and preferably it is in the range of 0.1 g / m 2 ~5 g / m 2 It is good. A particularly preferable lower limit of the coating amount is 0.2 g / m 2 And a particularly preferable upper limit is 3 g / m 2 It is.

[0084] The drying temperature of the coating solution applied to the outer surface of the base material layer 3 is not limited, and preferably it is in the range of 200°C to 300°C.

[0085] The thickness of the base material protective layer 2 is not limited, and preferably it is in the range of 0.1 μm to 6 μm. To surely adjust the thickness of the base material protective layer 2 within this preferred range, the coating amount of the coating solution is preferably in the range of 0.1 g / m 2 ~5 g / m 2 . The particularly preferred lower limit of the thickness of the base material protective layer 2 is 0.3 μm or more, and the particularly preferred upper limit is 2.0 μm.

[0086] Here, the inner and outer surfaces of each layer constituting the exterior material 1 may be subjected to surface activation treatments such as corona treatment, blast treatment, oxidation treatment, ozone treatment, etc. in order to improve or stabilize film formability, lamination processing, final product secondary processing suitability (e.g., pouch formation, embossing). For example, by subjecting at least one of the inner and outer surfaces of the base material layer 3 to corona treatment, film formability, lamination processing, final product secondary processing suitability, etc. can be improved or stabilized.

[0087] On the other hand, when the base material layer 3 includes a polyamide film and the outer surface of the base material layer 3 is formed on the outer surface of the polyamide film, it is preferable that the outer surface of the polyamide film is not corona-treated. In this case, it is easy to adjust the adhesion strength between the base material protective layer 2 and the base material layer 3 to a desired value.

[0088] (Barrier layer 4) The barrier layer 4 plays a role of imparting properties (e.g., gas barrier properties) to the exterior material 1 to block the intrusion of oxygen and moisture. The barrier layer 4 generally consists of a metal foil layer. The metal foil of the metal foil layer is not limited, and as the metal foil, aluminum foil, stainless steel foil, copper foil, nickel foil, titanium foil, metal clad foil, etc. are used, and particularly aluminum foil is preferably used.

[0089] The thickness of the barrier layer 4 is not limited, and preferably it is in the range of 20 μm to 100 μm. When the thickness of the barrier layer 4 is 20 μm or more, the generation of pinholes during rolling when manufacturing the metal foil can be suppressed. When the thickness of the barrier layer 4 is 100 μm or less, the processing stress acting on the exterior material 1 during forming processes such as deep drawing forming and overhang forming can be surely reduced, and the formability of the exterior material 1 can be surely improved. The particularly preferred lower limit of the thickness of the barrier layer 4 is 30 μm, and the particularly preferred upper limit is 80 μm.

[0090] When the barrier layer 4 is a metal foil layer, it is preferable that a base treatment such as a chemical conversion treatment is performed on at least the inner surface (that is, the surface on the side of the sealant layer 5) of the inner and outer surfaces of the metal foil to form a chemical conversion film (indicated by dot hatching) 3a. The formation of the chemical conversion film 4a can be performed by, for example, performing a chromate treatment or a non-chromium type chemical conversion treatment using a zirconium compound on the surface of the metal foil.

[0091] For example, when forming the chemical conversion film 4a by chromate treatment, an aqueous solution of any one of the following mixtures 1) to 3) is applied to the surface of the degreased metal foil and then dried.

[0092] 1) A mixture of phosphoric acid, chromic acid, and at least one of a metal salt of fluoride and a non-metal salt of fluoride 2) A mixture of phosphoric acid, any one of an acrylic resin, a chitosan derivative resin, and a phenolic resin, and at least one of chromic acid and a chromium (III) salt 3) A mixture of phosphoric acid, any one of an acrylic resin, a chitosan derivative resin, and a phenolic resin, at least one of chromic acid and a chromium (III) salt, and at least one of a metal salt of fluoride and a non-metal salt of fluoride.

[0093] The chromium adhesion amount of the chemical conversion film 4a is not limited, and preferably it is in the range of 0.1 mg / m 2 ~50 mg / m 2 and it is preferably 2 mg / m2 ~20 mg / m 2 is particularly preferably in this range. Such a chemical conversion film 4a with a chromium deposition amount can surely impart high corrosion resistance to the exterior material 1.

[0094] (Sealant layer 5) The sealant layer 5 plays a role of imparting heat sealability to the exterior material 1, and further has a role of providing the exterior material 1 with chemical resistance against highly corrosive electrolytes and the like.

[0095] The sealant layer 5 generally consists of a heat-sealable resin. The type of the heat-sealable resin is not limited, and typical heat-sealable resins include single substances and copolymers of polyolefin resins (e.g., polypropylene, polyethylene), and specifically, propylene-based resins such as unoriented polypropylene (CPP), inflation polypropylene (IPP), etc. can be mentioned. Further, as the propylene-based resin, in addition to a homopolymer of propylene (hPP), an ethylene-propylene copolymer containing ethylene and propylene as copolymerization components can be exemplified. Examples of the ethylene-propylene copolymer include an ethylene-propylene block copolymer (bPP), an ethylene-propylene random copolymer (rPP), etc. As the sealant layer 5, it is preferably to use an unoriented film (e.g., CPP film) of the above-mentioned heat-sealable resin.

[0096] Furthermore, the sealant layer 5 may be formed of either a single-layer film or a multi-layer film (including multiple layers) of a heat-sealable resin. The multi-layer film can be produced by co-extrusion or the like. When the heat-sealable resin is, for example, a polypropylene-based resin, as a multi-layer film, a three-layer film (i.e., rPP / bPP / rPP film) in which rPP films as coating layers (the first layer and the third layer) are laminated and integrated on both sides of a bPP film as an intermediate layer (the second layer), a three-layer film (i.e., rPP / hPP / rPP film) in which rPP films as coating layers (the first layer and the third layer) are laminated and integrated on both sides of an hPP film as an intermediate layer (the second layer), etc. are preferably used. When an rPP / bPP / rPP film is used as the multi-layer film, the layer thickness ratio is not limited and is preferably in the following range.

[0097] rPP / bPP / rPP = (1 to 3) : (4 to 8) : (1 to 3).

[0098] Also, the sealant layer 5 may contain a fatty acid amide-based lubricant. In this case, the content of the lubricant in the sealant layer 5 is preferably in the range of 500 ppm to 4000 ppm.

[0099] The thickness of the sealant layer 5 is not limited and is preferably in the range of 20 μm to 100 μm. A particularly preferred lower limit of the thickness of the sealant layer 5 is 30 μm, and a particularly preferred upper limit is 80 μm. Also, even when the sealant layer 5 is formed of a multi-layer film, the total thickness of the multi-layer film is preferably in the above range.

[0100] (Outer adhesive layer 6) The outer adhesive layer 6 is a layer responsible for the adhesion (bonding) between the base material layer 3 and the barrier layer 4 and is interposed between the base material layer 3 and the barrier layer 4. The thickness of the outer adhesive layer 6 is not limited and is preferably in the range of 2 μm to 5 μm.

[0101] The type of the adhesive of the outer adhesive layer 6 is not limited, and for example, a two-component curable adhesive can be mentioned. As the two-component curable adhesive, polyurethane-based adhesives, acrylic-based adhesives, polyacrylate-based adhesives, modified polypropylene-based adhesives, polyester-based adhesives, polyamide-based adhesives, epoxy-based adhesives, etc. are used. Further, as the two-component curable adhesive, a first liquid (main agent) composed of one or more polyols selected from the group consisting of polyurethane-based polyols, polyester-based polyols, polyether-based polyols, and polyester urethane-based polyols, and a second liquid (curing agent) composed of isocyanate are used. Among them, it is preferable to use a two-component curable adhesive composed of a first liquid composed of one or more polyols selected from the group consisting of polyester-based polyols and polyester urethane-based polyols and a second liquid (curing agent) composed of isocyanate.

[0102] (Inner Adhesive Layer 7) The inner adhesive layer 7 has adhesive components such as an adhesive and an adhesive resin interposed between the barrier layer 4 and the sealant layer 5, and the barrier layer 4 and the sealant layer 5 are adhesively bonded (joined) in a laminated state through this adhesive component. The thickness of the inner adhesive layer 7 is not limited, and preferably it is in the range of 1 μm to 5 μm.

[0103] The type of the adhesive component is not limited. As the adhesive component, the same adhesive as the adhesive of the above-mentioned outer adhesive layer 6 may be used, or an adhesive resin such as a polyolefin resin such as polyolefin, carboxylic acid-modified polyolefin, and metal-modified polyolefin, a polyvinyl acetate-based resin, a (meth)acrylic-based resin, and an amino resin may be used. Further, these adhesive resins may be used alone or in combination of two or more.

[0104] When an adhesive is used as the adhesive component, the method of adhering the barrier layer 4 and the sealant layer 5 is not limited, and for example, it is as follows.

[0105] The adhesive composition is applied in layers on the barrier layer 4 or the sealant layer 5 by a gravure coating method, a reverse roll coating method, or the like. After evaporating the solvent in the coating layer to form a dry film of the coating layer, the barrier layer 4 and the sealant layer 5 are bonded together, and then the coating layer is cured according to the curing conditions of the adhesive composition to bond the barrier layer 4 and the sealant layer 5. Incidentally, the bonding of the base material layer 3 and the barrier layer 4 by the above-described outer adhesive layer 6 can also be performed in the same manner.

[0106] When an adhesive resin is used as the adhesive component of the inner adhesive layer 7, the method of bonding the barrier layer 4 and the sealant layer 5 is not limited, and the following methods can be mentioned as the bonding method.

[0107] That is, a method of laminating the sealant layer 5 on the barrier layer 4 by co-extruding an adhesive resin and a heat-fusible resin for forming the sealant layer 5 on the barrier layer 4 (extrusion lamination method), a method of previously forming a laminate in which the adhesive resin and the sealant layer 5 are laminated and laminating this laminate on the barrier layer 4 by a heat lamination method, a method of bonding the barrier layer 4 and the sealant layer 5 while pouring a molten adhesive resin between the barrier layer 4 and the sealant layer 5 (sand lamination method), etc. can be mentioned.

[0108] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be variously modified without departing from the gist of the present invention.

Example

[0109] Specific examples and comparative examples of the present invention are shown below. However, the present invention is not limited to the following examples.

[0110]

Table 1

[0111]

Table 2

[0112] In Examples 1 to 4 and Comparative Examples 1 to 2, an exterior material 1 for a battery having the layer structure shown in FIG. 1 was manufactured. In Comparative Example 3, an exterior material 1 for a battery having a layer structure lacking the base material protective layer 2 was manufactured from the layer structure shown in FIG. 1. In Examples 1 to 4 and Comparative Examples 1 to 3, for the sake of easy understanding of the layer structure of the exterior material 1, these examples and comparative examples will be described using the same reference numerals as those used in the above-described embodiment.

[0113] <Example 1> An aluminum foil with a thickness of 35 μm was prepared as the barrier layer 4. The material of the aluminum foil is an aluminum alloy symbol A8021-O material defined in JIS H4160:2006. Chemical conversion coatings 4a were formed on both the inner and outer surfaces of this aluminum foil. The formation of this chemical conversion coating 4a was carried out by applying a chemical conversion treatment liquid composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol to both surfaces of the aluminum foil and then drying at 180°C. The chromium adhesion amount of the chemical conversion coating 4a was 10 mg / m 2 per one side of the aluminum foil.

[0114] A biaxially stretched 6-nylon film with a thickness of 15 μm was prepared as the base material layer 3. In this biaxially stretched 6-nylon film, its inner surface (i.e., the surface on the barrier layer 4 side) was subjected to corona treatment, and its outer surface (i.e., the surface on the base material protective layer 2 side) was not subjected to corona treatment. Therefore, the inner surface of the biaxially stretched 6-nylon film is the corona-treated surface, and its outer surface is the non-corona-treated surface.

[0115] A CPP film with a thickness of 30 μm was prepared as the sealant layer 5.

[0116] A two-component curable urethane-based adhesive was prepared as the adhesive for the outer adhesive layer 6.

[0117] A two-component curable maleic acid-modified polypropylene adhesive was prepared as the adhesive component for the inner adhesive layer 7.

[0118] Next, the inner surface (corona-treated surface) of the biaxially stretched 6-nylon film (base material layer 3) was dry-laminated to the outer surface of the aluminum foil (barrier layer 4) via the outer adhesive layer 6, and then the outer adhesive layer 6 was aged at 60°C for 7 days.

[0119] Next, a polyamideimide resin with a glass transition point Tg of 260°C was dissolved in a mixed solvent of ethanol:toluene = 1:1 (mass ratio) without adding its curing agent to prepare a resin solution with a polyamideimide resin solid content concentration of 25% by mass. Further, a predetermined amount of ethylene bisoleic acid amide was added as a lubricant to this resin solution and uniformly dispersed to prepare a coating solution for forming the base material protective layer. Note that the content of the lubricant in this coating solution, that is, the ratio of the lubricant to the total amount of the resin and the lubricant in this coating solution, is the same as the content of the lubricant in the base material protective layer 2 described later.

[0120] Next, this coating solution was applied to the outer surface (non-corona-treated surface) of the biaxially stretched 6-nylon film (base material layer 3) by the gravure roll coating method, and this coating solution was dried at 100°C for 60 seconds to form a base material protective layer 2 composed of a resin composition containing a lubricant and a polyamideimide resin.

[0121] The resin amount in the base material protective layer 2 is as described in the "resin amount" column in Table 1, and the content of the lubricant in the base material protective layer 2 is as described in the "content" column in Table 1. Note that in the "corona treatment" column of "base material layer" in Table 1, "none" means that the outer surface of the base material layer (biaxially stretched 6-nylon film) 3 is not corona-treated, and "yes" means that the outer surface of the base material layer 3 is corona-treated. In Example 1, the outer surface of the base material layer 3 is formed on the outer surface of the biaxially stretched 6-nylon film, and the outer surface of this biaxially stretched 6-nylon film is not corona-treated, so the "corona treatment" column is "none".

[0122] Next, a CPP film (sealant layer 5) was laminated on the inner surface of the aluminum foil (barrier layer 4) via an inner adhesive layer 7, and the aluminum foil and the CPP film were sandwiched between a rubber nip roll and a laminating roll heated to 100 °C and pressed together by the dry lamination method. As a result, a sheet-like laminate in which a substrate protective layer 2, a biaxially stretched 6-nylon film (substrate layer 3), an aluminum foil (barrier layer 4), and a CPP film (sealant layer 5) were laminated and integrated in order from the outside to the inside was produced.

[0123] Next, the exterior material 1 was manufactured by aging the laminate at 40 °C for 7 days. In the exterior material 1, the thickness of the substrate protective layer 2 was as described in the "thickness" column in Table 1, the thickness of the outer adhesive layer 6 was 3 μm, and the thickness of the inner adhesive layer 7 was 2.0 μm.

[0124] <Example 2> A polyamide-imide resin having a glass transition point Tg of 255 °C was dissolved in a mixed solvent of N-methyl-2-pyrrolidone:xylene:methyl ethyl ketone = 3.5:2.5:1 (mass ratio) without adding its curing agent to the polyamide-imide resin to prepare a resin solution having a polyamide-imide resin solid content concentration of 30% by mass. Further, a predetermined amount of ethylene bisoleic acid amide was added as a lubricant to this resin solution and uniformly dispersed to prepare a coating liquid for forming a substrate protective layer.

[0125] Using this coating liquid, the exterior material 1 was manufactured in the same manner as the manufacturing method of the exterior material in Example 1.

[0126] <Example 3> A polyamide-imide resin having a glass transition point Tg of 300 °C was dissolved in an N-methyl-2-pyrrolidone solvent without adding its curing agent to the polyamide-imide resin to prepare a resin solution having a polyamide-imide resin solid content concentration of 15% by mass. Further, a predetermined amount of ethylene bisoleic acid amide was added as a lubricant to this resin solution and uniformly dispersed to prepare a coating liquid for forming a substrate protective layer.

[0127] The exterior material 1 was manufactured in the same manner as the manufacturing method of the exterior material of Example 1 using this coating solution.

[0128] <Example 4> A polyamideimide resin having a glass transition point Tg of 320 °C was dissolved in an N-methyl-2-pyrrolidone solvent without adding its curing agent thereto to prepare a resin solution having a polyamideimide resin solid content concentration of 14% by mass. Further, a predetermined amount of N-stearyloleic acid amide as a lubricant was added to this resin solution and uniformly dispersed therein to prepare a coating solution for forming a base material protective layer.

[0129] The exterior material 1 was manufactured in the same manner as the manufacturing method of the exterior material of Example 1 using this coating solution.

[0130] <Comparative Example 1> A biaxially stretched 6-nylon film having a thickness of 15 μm was prepared as the base material layer 3. In this biaxially stretched 6-nylon film, corona treatment was applied to both the inner surface and the outer surface thereof. Therefore, the inner surface and the outer surface of the biaxially stretched 6-nylon film are corona-treated surfaces.

[0131] An exterior material was manufactured in the same manner as the manufacturing method of the exterior material of Example 1 using this biaxially stretched 6-nylon film (base material layer 3).

[0132] <Comparative Example 2> HDI-based isocyanate as a curing agent was blended with the polyamideimide resin having a glass transition point Tg of 260 °C used in Example 1 at a ratio of polyamideimide resin:HDI-based isocyanate = 100:10 (mass ratio), and dissolved in a mixed solvent of ethanol:toluene = 1:1 (mass ratio) to prepare a resin solution having a polyamideimide resin solid content concentration of 25% by mass. Further, the same lubricant as used in Example 1 was added to this resin solution in the same addition amount as in Example 1 and uniformly dispersed therein to prepare a coating solution for forming a base material protective layer.

[0133] An exterior material was manufactured in the same manner as the manufacturing method of the exterior material of Example 1 using this coating solution.

[0134] <Comparative Example 3> An exterior material was produced in the same manner as in the production method of the exterior material of Example 1, except that the base material protective layer 2 was not formed on the outer surface of the biaxially stretched 6-nylon film (base material layer 3).

[0135] (Seal bar adhesion test) The ease of adhesion of the exterior materials of Examples 1 to 4 and Comparative Examples 1 to 3 to the seal bar was evaluated by the following method.

[0136] Fig. 7 shows an outline of the method of the seal bar adhesion test.

[0137] A rectangular sample with a width of 50 mm and a length of 100 mm was taken from each exterior material 1. Then, the sample was folded in half at the middle position of its long side so that the outer surface 1b (i.e., the surface on the side of the base material protective layer 2) of the sample was on the outside and the inner surface 1a (i.e., the surface on the side of the sealant layer 5) of the sample was on the inside, to produce a test piece 41 with a width of 50 mm × 50 mm. One end portion 42 of this test piece 41 has the two short sides of the rectangular sample aligned and overlapping, and the other end portion 43 is in a loop. Then, a kite string 47 was passed through the loop at the other end portion 43 to form a loop.

[0138] One end portion 42 of this test piece 41 was heat-sealed by sandwiching it between a heated upper seal bar 45 made of aluminum (seal width 5 mm) and a heated lower seal bar 46 made of aluminum covered with a fluororesin coating layer 46a (seal width 5 mm). The heat sealing was performed under two types of temperature conditions: a seal temperature of 210°C × 0.3 MPa × 3 seconds and a seal temperature of 230°C × 0.3 MPa × 3 seconds.

[0139] After heat sealing, the lower seal bar 46 was separated from the test piece 41, and the test piece 41 was attached to the upper seal bar 45. Then, the hook 48a of a push-pull gauge (model DPX-10, manufactured by IMADA) 48 was hung on the annular kite string 47 passed through the other end portion 43 of the test piece 41, and the test piece 41 was pulled horizontally until it separated from the upper seal bar 45, and the tensile strength when the test piece 41 separated was measured, and this was taken as the adhesion strength of the exterior material 1 to the seal bar 45. Then, the tensile strength (adhesion strength) was evaluated in four grades of A, B, C, and D based on the following criteria. The results were described in the "Seal bar adhesion test" column in Table 2. In addition, the numerical value in parentheses in the "Tensile strength" column means the tensile strength (unit: kgf), and 1 kgf = 9.8 N.

[0140] A: Tensile strength is less than 0.1 kgf B: Tensile strength is 0.1 kgf or more and less than 0.8 kgf C: Tensile strength is 0.8 kgf or more and less than 1.0 kgf D: Tensile strength is 1.0 kgf or more.

[0141] (Forming processability) Rectangular test specimens (blanks) with a length of 100 mm and a width of 125 mm were taken from each exterior material 1. Then, using a press working machine (product number: TP-25C-XZ) manufactured by AMADA Co., Ltd. equipped with a punch (punch shape: 33 mm × 54 mm, corner R: 2 mm, punch shoulder R: 1.3 mm) and a die (die shape: die shoulder R: 1 mm) as a deep drawing forming machine, the test specimens were deep drawn and formed by changing the forming depth in increments of 0.5 mm to produce the exterior case body 21. The deep drawing forming process was performed in such a manner that the pressing surface of the punch was brought into contact with the inner surface of the test material (i.e., the surface on the sealant layer 5 side of the exterior material 1) and the outer surface of the test specimen (i.e., the surface on the base material protection layer 2 side of the exterior material 1) was projected outward.

[0142] Then, at the corner of the exterior case body 21, the presence or absence of pinholes and cracks was visually observed by the light transmission method in a dark room, and the maximum forming depth at which good forming can be performed without the occurrence of pinholes and cracks in the test specimens was examined. And the formability of the test specimens was evaluated in four grades of A, B, C, and D based on the following criteria. The results were described in the "Formability" column in Table 2.

[0143] A: The maximum forming depth is 6 mm or more B: The maximum forming depth is 5 mm or more and less than 6 mm C: The maximum forming depth is 4 mm or more and less than 5 mm D: The maximum forming depth is less than 4 mm.

[0144] (Adhesion strength test between the substrate protection layer 2 and the substrate layer 3) The adhesion strength between the substrate protection layer 2 and the substrate layer 3 in each exterior material 1 of Examples 1 to 4 and Comparative Examples 1 and 2 was measured under the following conditions and methods.

[0145] Here, for a T-shaped test piece with a width of 15 mm produced by adhering a support to the outer surface of the exterior material 1 formed by the outer surface of the substrate protection layer 2 with an adhesive, the peeling strength when the support and the exterior material 1 are peeled by performing a T-shaped peeling test in accordance with JIS K6854-3 was defined as the adhesion strength between the substrate protection layer 2 and the substrate layer 3 in the exterior material 1. The specific measurement method (test method) for the adhesion strength between the substrate protection layer 2 and the substrate layer 3 is as follows.

[0146] A support was prepared by bonding a biaxially stretched 6-nylon film used as the base material layer 3 in Example 1 and an aluminum foil used as the barrier layer 4 in Example 1 with an adhesive. The surface on the aluminum foil side of the support was used as the adhesive surface, and a two-component curable urethane-based adhesive used as the adhesive for the outer adhesive layer 6 in Example 1 was applied to this adhesive surface. Then, the adhesive surface of the support was overlapped with the outer surface 1b of the exterior material 1 composed of the outer surface of the base material protection layer 2, and the support and the exterior material 1 were laminated by the dry lamination method by sandwiching them between a rubber nip roll and a laminating roll heated to 100 °C, and the support was adhered to the outer surface 1b of the exterior material 1 by aging at 60 °C for 7 days. Thereafter, the mutually adhered support and exterior material 1 were cut into strips with a width of 15 mm to produce T-shaped test pieces. For this T-shaped test piece, a T-peel test was performed using a tensile tester under the condition of a test speed of 100 m / min in accordance with JIS K6854-3, and the peel strength when the support and the exterior material 1 were peeled was measured as the adhesion strength between the base material protection layer 2 and the base material layer 3.

[0147] This measurement was performed on 5 test pieces, and the arithmetic mean value of the measured values was described in the "Adhesion Strength Test" column in Table 2 as the adhesion strength between the base material protection layer 2 and the base material layer 3.

[0148] (Peeling state of the base material protection layer 2) After the above T-peel test, the outer surface 1b of the peeled exterior material 1 was subjected to IR analysis and visual observation to examine the peeling state of the base material protection layer 2 from the base material layer 3 of the exterior material 1. Then, the peeling state of the base material protection layer 2 was evaluated in three levels of A, B, and C based on the following criteria. The results were described in the "Peeling State of the Base Material Protection Layer" column in Table 2.

[0149] A: Complete peeling of the base material protection layer B: Partial peeling of the base material protection layer C: No peeling of the base material protection layer.

[0150] (Evaluation of the adhesion between the outer surface 1b of the exterior material 1 and the mounting tape) After the above T-shaped peel test, a cellophane tape "3M Scotch tape #610" was adhered to the outer surface 1b of the peeled exterior material 1 as an attachment tape, and a pressure roller with a mass of 2 kg was reciprocated twice on the attachment tape. After 5 minutes had elapsed, the attachment tape was peeled from the outer surface 1b of the exterior material 1 using a tensile testing machine, and the adhesion strength between the outer surface 1b of the exterior material 1 and the attachment tape was measured. Then, the adhesion strength was evaluated in three levels of A, B, and C based on the following criteria. The results were described in the column of "Adhesion to the attachment tape" in Table 2.

[0151] A: 9 N / 25.4 mm or more B: 6 N / 25.4 mm or more and less than 9 N / 25.4 mm C: Less than 6 N / 25.4 mm.

[0152] (Print adhesion) After the above T-shaped peel test, a barcode (dot size: diameter 0.25 mm) was printed in black ink on the outer surface 1b of the peeled exterior material 1 using an inkjet printer. Next, the above cellophane tape was adhered to the printed portion of the outer surface 1b of the exterior material 1, and a pressure roller with a mass of 2 kg was reciprocated twice on the cellophane tape. Immediately afterwards, the cellophane tape was peeled from the outer surface 1b of the exterior material 1, and the adhesion of the barcode printing on the outer surface 1b of the exterior material 1 was examined. Then, the print adhesion on the outer surface 1b of the exterior material 1 was evaluated in three levels of A, B, and C based on the following criteria from the viewpoints of whether the barcode printing was peeled from the outer surface 1b of the exterior material 1 and whether the barcode could be read by a barcode reader, and the results were described in the column of "Print adhesion" in Table 2.

[0153] A: No peeling of the printing and the barcode can be read B: There is partial peeling of the printing and the barcode can be read C: Complete peeling of the printing and the barcode cannot be read.

[0154] As shown in the columns of "Adhesion Strength Test" and "Peeling State of Substrate Protection Layer" in Table 2, in Examples 1 to 4, since the adhesion strength between the substrate protection layer 2 and the substrate layer 3 in the exterior material 1 was lower than 3.0 N / 15 mm, when the support and the exterior material 1 were peeled, it was confirmed that the substrate protection layer 2 was completely peeled from the substrate layer 3 with respect to the substrate layer 3. Therefore, when the protective tape 10 was attached to the outer surface 1b of the exterior material 1 in Examples 1 to 4 and then the protective tape 10 was peeled from the outer surface 1b of the exterior material 1, it was considered that the substrate protection layer 2 was peeled from the substrate layer 3 integrally with the protective tape 10. Furthermore, as shown in the columns of "Adhesion to Mounting Tape" and "Printing Adhesion" in Table 2, after the substrate protection layer 2 was peeled in this way in the exterior material 1 of Examples 1 to 4, it was confirmed that the outer surface 1b of the exterior material 1 had high adhesion to the mounting tape and high printing adhesion.

Industrial Applicability

[0155] The present invention can be used for exterior materials for power storage devices such as various batteries (including various capacitors), exterior cases for power storage devices, power storage devices, etc.

Explanation of Reference Numerals

[0156] 1: Exterior material 1a: Inner surface of exterior material 1b: Outer surface of exterior material 2: Substrate protection layer 3: Substrate layer 4: Barrier layer 5: Sealant layer 6: Outer adhesive layer 7: Inner adhesive layer 10: Protective tape 20: Exterior case 21: Exterior case body 25: Exterior outer lid 50: Battery (power storage device) 51: Battery body (power storage device body) HS: Heat seal part

Claims

1. An exterior material for a power storage device in which at least a base material protective layer, a base material layer, a barrier layer, and a sealant layer are laminated in order from the outside to the inside, wherein the base material protective layer is made of a resin composition containing a lubricant and a resin, and the exterior material for a power storage device has an adhesion strength between the base material protective layer and the base material layer of 3.0 N / 15 mm or less.

2. The exterior material for a power storage device according to claim 1, wherein the resin contained in the base material protective layer contains a polyamideimide resin not containing a curing agent.

3. The exterior material for a power storage device according to claim 1 or 2, wherein the base material layer contains a polyamide film and the outer surface of the polyamide film is not corona-treated.

4. The exterior material for a power storage device according to claim 1 or 2, wherein the glass transition point of the resin contained in the base material protective layer is 220°C or higher.

5. An exterior case for a power storage device, in which a recess for housing a power storage device body is formed by deep drawing or protrusion forming in the exterior material for a power storage device according to claim 1 or 2.

6. A power storage device in which a power storage device body is externally packaged with the exterior material for a power storage device according to claim 1 or 2.

7. A method for manufacturing a power storage device, which comprises preparing an exterior material in which at least a base material protective layer, a base material layer, a barrier layer, and a sealant layer are laminated in order from the outside to the inside, attaching a protective tape to the outer surface of the exterior material, and then peeling the protective tape from the outer surface of the exterior material to peel the base material protective layer from the base material layer integrally with the protective tape.

Images