Exterior for all-solid-state battery and all-solid-state battery using the same

Abstract

To provide an exterior material for power storage device which can secure the excellent lamination strength under both of a room-temperature environment and a high-temperature environment, and has the excellently deep-drawing moldability, and a power storage device using the same.SOLUTION: An exterior material for power storage device is made of a laminate that includes at least a substrate layer 11, a first adhesive layer 12a, a barrier layer 13, a second adhesive layer 12b and a sealant layer 16 in this order. When the substrate layer is removed, the first adhesive layer is exposed, and measurement is performed with the attenuated total reflection of the Fourier transformation infrared spectroscopic analysis method from the outermost surface side of the exposed adhesive layer, a transmission factor T0 of a baseline, a minimum value T1 of the transmission factor detected within a range from 2100 cm-1 to 2400 cm-1, and a minimum value T2 of the transmission factor detected within a range from 1670 cm-1 to 1700 cm-1 satisfy the relationship of 0.06≤(T0-T1) / (T0-T2)≤0.4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an exterior material for a power storage device that is excellent in both heat resistance and moldability, and to a power storage device using the same. [Background technology]

[0002] Known examples of power storage devices include secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, and lead-acid batteries, as well as electrochemical capacitors such as electric double-layer capacitors. Due to the miniaturization of portable devices and limitations on installation space, there is a demand for further miniaturization of power storage devices, and lithium-ion batteries with high energy density have attracted attention. While metal cans have traditionally been used as the exterior materials for lithium-ion batteries, multilayer films have begun to be used, which are lightweight, have excellent heat dissipation properties, and can be produced at low cost.

[0003] Lithium-ion batteries that use the above multilayer film as an exterior material are called laminated lithium-ion batteries. The exterior material covers the battery contents (positive electrode, separator, negative electrode, electrolyte, etc.) and prevents moisture from penetrating into the battery. Laminated lithium-ion batteries are manufactured, for example, by forming a recess in part of the exterior material by cold forming, accommodating the battery contents in the recess, folding back the remaining part of the exterior material, and heat-sealing the edges (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-101765 Summary of the Invention [Problem to be solved by the invention]

[0005] Meanwhile, research and development is being conducted on power storage devices known as all-solid-state batteries as the next generation of lithium-ion batteries. All-solid-state batteries are characterized by using a solid electrolyte instead of an organic electrolyte solution as the electrolyte material. While lithium-ion batteries cannot be used at temperatures higher than the boiling point of the electrolyte solution (approximately 80°C), all-solid-state batteries can be used at temperatures exceeding 100°C, and the conductivity of lithium ions can be increased by operating them under high temperature conditions (for example, 100 to 150°C).

[0006] However, when a laminated all-solid-state battery is manufactured using such a multilayer film as an exterior material, if the exterior material has insufficient heat resistance, interlayer adhesion cannot be ensured in a high-temperature environment, resulting in a decrease in laminate strength and a risk of poor sealing of the all-solid-state battery package. As shown in Patent Document 1, the exterior material has a structure in which, for example, a substrate layer, a metal foil layer (barrier layer), and a sealant layer are laminated via an adhesive layer or the like. However, adhesion between the substrate layer and the metal foil layer is likely to decrease in a high-temperature environment. Furthermore, while epoxy-based adhesives are known as heat-resistant adhesives, the cured product of an epoxy-based adhesive tends to be highly brittle, and the deep-drawability and laminate strength at room temperature required for the exterior material are likely to be insufficient.

[0007] The present disclosure has been made in view of the above-mentioned problems, and aims to provide an exterior material for a power storage device that can ensure excellent laminate strength both in room temperature environments and high temperature environments and also has excellent deep-draw formability, and a power storage device using the same. [Means for solving the problem]

[0008] In order to solve the above problems, the present disclosure provides a laminate including at least a base layer, a first adhesive layer, a barrier layer, a second adhesive layer, and a sealant layer in this order, The substrate layer is removed to expose the first adhesive layer, and when measured by attenuated total reflection of Fourier transform infrared spectroscopy from the outermost surface side of the exposed adhesive layer, the transmittance of the baseline T0 and the transmittance of the 2100 cm-1 From 2400cm -1 The minimum transmittance T1 detected in the range of 1670cm -1 From 1700cm -1 The present invention provides an exterior material for an electricity storage device, characterized in that the minimum value T2 of transmittance detected within this range satisfies the relationship 0.06≦(T0−T1) / (T0−T2)≦0.4.

[0009] When the relationship 0.06≦(T0-T1) / (T0-T2)≦0.4 is satisfied, the tensile strength and breaking elongation of the first adhesive layer become closer to those of each layer (mainly the barrier layer and substrate), resulting in improved moldability. Furthermore, when a molded product using the packaging material of the present invention is exposed to a high-temperature environment (150°C), the reaction between unreacted curing agents is promoted, raising the Tg of the first adhesive layer and improving heat resistance.

[0010] In the packaging material for a power storage device, the first adhesive layer may contain a polyfunctional isocyanate compound, and the polyfunctional isocyanate compound may be at least one polyfunctional isocyanate compound selected from the group consisting of alicyclic isocyanate polymers and isocyanate polymers containing an aromatic ring in the molecular structure. By specifying the structure of the isocyanate compound to be alicyclic and containing a benzene ring, it is possible to improve initial adhesion strength and heat resistance.

[0011] In the above-mentioned packaging material for a power storage device, the first adhesive layer may contain a urethane resin formed from at least one polyol selected from the group consisting of polyester polyol, acrylic polyol, and polycarbonate diol, and the polyfunctional isocyanate polymer. When the polyol component is selected from the three types of polyester polyol, acrylic polyol, and polycarbonate diol (PCD), heat resistance and moldability are improved. Among them, polyester polyol is preferred.

[0012] In the packaging material for a power storage device, the ratio of the number of isocyanate groups contained in the polyfunctional isocyanate polymer to the number of hydroxyl groups contained in the polyol may be 5 to 60. By setting the NCO / OH ratio to a value within this range, the laminate strength in a high-temperature environment can be improved and a decrease in formability can be prevented.

[0013] In the packaging material for a power storage device, the coating amount of the urethane resin after drying is 2.0 g / m 2 More than 6.0g / m 2 If the coating amount is less than 2.0 g, the thickness of the adhesive layer will be small, which may result in a decrease in stress dispersion and a decrease in moldability. On the other hand, if the coating amount is increased, the adhesive layer will become thicker, which will improve moldability due to improved stress dispersion, etc. However, if the coating amount is more than 6.00 g / m 2 Even if the amount is increased, no significant improvement in formability is observed, and from the viewpoint of cost, etc., the upper limit of the amount of coating is 6.00 g / m 2 It is preferable to do so.

[0014] In the packaging material for a power storage device, the barrier layer may be made of aluminum foil, which has an excellent overall balance of barrier properties, stretchability, cost, and the like.

[0015] In the packaging material for a power storage device, the barrier layer may have a thickness of 15 to 100 μm, which provides good formability and reduces costs.

[0016] The above-mentioned packaging material for a power storage device may have a corrosion prevention treatment layer between the first adhesive layer and the barrier layer, between the second adhesive layer and the barrier layer, or both. This improves chemical adhesion with the adhesive layer, thereby improving formability. Furthermore, this can provide corrosion resistance to hydrogen sulfide, which is generated when a sulfide is used in the solid electrolyte.

[0017] In the packaging material for a power storage device, the substrate may be made of a polyamide film or a polyester film. By using a substrate having excellent toughness and heat resistance, heat resistance and moldability can be improved.

[0018] The packaging material for a power storage device may be for an all-solid-state battery.

[0019] The present disclosure also provides an electricity storage device including: an electricity storage device main body; a current extracting terminal extending from the electricity storage device main body; and an exterior material for an electricity storage device according to the present disclosure, the exterior material sandwiching the current extracting terminal and housing the electricity storage device main body. The electricity storage device may be an all-solid-state battery. [Effects of the Invention]

[0020] According to the present disclosure, it is possible to provide an exterior material for a power storage device that can ensure excellent laminate strength both in room temperature environments and high temperature environments and also has excellent deep draw formability, and a power storage device using the same. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic cross-sectional view of an exterior packaging material for a power storage device according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic cross-sectional view of an exterior packaging material for a power storage device according to an embodiment of the present disclosure. [Figure 3] 1 is a perspective view of an electricity storage device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present disclosure will be described in detail below with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional ratios of the drawings are not limited to those shown.

[0023] [Exterior materials for energy storage devices] Fig. 1 is a cross-sectional view schematically illustrating one embodiment of an exterior packaging material for an energy storage device according to the present disclosure. As shown in Fig. 1, an exterior packaging material (exterior packaging material for an energy storage device) 10 of this embodiment is a laminate including a substrate layer 11, a first adhesive layer 12a provided on one side of the substrate layer 11, a barrier layer 13 provided on the side of the first adhesive layer 12a opposite the substrate layer 11 and having first and second corrosion prevention treatment layers 14a, 14b on both sides, a second adhesive layer 12b provided on the side of the barrier layer 13 opposite the first adhesive layer 12a, and a sealant layer 16 provided on the side of the second adhesive layer 12b opposite the barrier layer 13. The first corrosion prevention treatment layer 14a is provided on the surface of the barrier layer 13 facing the substrate layer 11, and the second corrosion prevention treatment layer 14b is provided on the surface of the barrier layer 13 facing the sealant layer 16. In the packaging material 10, the base material layer 11 is the outermost layer and the sealant layer 16 is the innermost layer. That is, the packaging material 10 is used with the base material layer 11 facing the exterior side of the electricity storage device and the sealant layer 16 facing the interior side of the electricity storage device.

[0024] In the packaging material 10 of this embodiment, when the base material layer 11 is removed and the exposed first adhesive layer 12a is measured from the outermost surface side by attenuated total reflection in Fourier transform infrared spectroscopy, the transmittance T0 of the baseline and the transmittance T2 of the 2100 cm 3 are measured as described above. -1 From 2400cm -1 The minimum transmittance T1 detected in the range of 1670cm -1 From 1700cm -1 The minimum transmittance T2 detected within this range satisfies the relationship 0.06≦(T0−T1) / (T0−T2)≦0.4.

[0025] Each layer that constitutes the packaging material 10 will now be described in detail.

[0026] <Base material layer 11> The base material layer 11 provides heat resistance in the sealing process when manufacturing the electricity storage device and plays a role in suppressing the occurrence of pinholes that may occur during molding and distribution. In particular, in the case of an exterior material for a large-scale electricity storage device, the base material layer 11 can also provide scratch resistance, chemical resistance, insulation, etc.

[0027] The base layer 11 is preferably a layer made of a resin film formed from an insulating resin. Examples of the resin film include stretched or unstretched films such as polyester film, polyamide film, polyimide film, and polypropylene film. The base layer 11 may be a single-layer film made of any of these resin films, or a laminated film made of two or more of these resin films.

[0028] Among these, polyester film and polyamide film are preferred as the base layer 11 due to their excellent formability, and polyester film is more preferred. These films are preferably biaxially stretched films. Examples of polyester resins constituting polyester films include polyethylene terephthalate (PET). Examples of polyamide resins constituting polyamide films include nylon 6, nylon 6,6, copolymers of nylon 6 and nylon 6,6, nylon 6,10, polymetaxylylene adipamide (MXD6), nylon 11, and nylon 12. Among polyamide films, nylon 6 (ONy) is preferred due to its excellent heat resistance, puncture strength, and impact strength.

[0029] Examples of the stretching method for the biaxially stretched film include sequential biaxial stretching, tubular biaxial stretching, simultaneous biaxial stretching, etc. From the viewpoint of obtaining better deep drawability, the biaxially stretched film is preferably one stretched by the tubular biaxial stretching method.

[0030] Furthermore, the substrate layer 11 preferably has a peak melting temperature higher than that of the sealant layer 16. When the sealant layer 16 has a multilayer structure, the peak melting temperature of the sealant layer 16 refers to the peak melting temperature of the layer with the highest peak melting temperature. The peak melting temperature of the substrate layer 11 is preferably 290°C or higher, more preferably 290 to 350°C. Examples of resin films that can be used as the substrate layer 11 and have a peak melting temperature within the above range include nylon film, PET film, polyamide film, polyimide film, and polyphenylene sulfide film (PPS film). A commercially available film may be used as the substrate layer 11, or the substrate layer 11 may be formed by coating (application of a coating liquid and drying). The substrate layer 11 may have a single-layer structure or a multilayer structure, and may be formed by coating a thermosetting resin. The substrate layer 11 may also contain various additives (e.g., flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, tackifiers, etc.).

[0031] The difference (T11-T16) between the peak melting temperature T11 of the base material layer 11 and the peak melting temperature T16 of the sealant layer 16 is preferably 20°C or more. When this temperature difference is 20°C or more, deterioration of the appearance of the packaging material 10 due to heat sealing can be more sufficiently suppressed.

[0032] The thickness of the substrate layer 11 is preferably 5 to 50 μm, more preferably 6 to 40 μm, even more preferably 10 to 30 μm, and particularly preferably 12 to 30 μm. When the thickness of the substrate layer 11 is 5 μm or more, the pinhole resistance and insulating properties of the packaging material for an electricity storage device 10 tend to be improved. If the thickness of the substrate layer 11 exceeds 50 μm, the total thickness of the packaging material for an electricity storage device 10 increases, which is undesirable because it may be necessary to reduce the electrical capacity of the battery.

[0033] <First adhesive layer 12a> The first adhesive layer 12a is a layer that bonds the base material layer 11 and the barrier layer 13. In the packaging material 10 of this embodiment, the first adhesive layer 12a contains a urethane resin formed from at least one polyol selected from the group consisting of polyether polyol, polyester polyol, acrylic polyol, and polycarbonate diol, and a polyfunctional isocyanate compound, and the polyfunctional isocyanate compound is made of at least one polyfunctional isocyanate compound selected from the group consisting of alicyclic isocyanate polymers and isocyanate polymers containing an aromatic ring in the molecular structure.

[0034] Furthermore, when the first adhesive layer 12a is exposed by peeling off the base material layer 11 and measured from the outermost surface side of the exposed first adhesive layer 12a by attenuated total reflection in Fourier transform infrared spectroscopy, the transmittance of the base line is T0 and the transmittance of the first adhesive layer 12a is 2100 cm -1 From 2400cm -1 The minimum transmittance T1 detected in the range of 1670cm -1 From 1700cm -1 The minimum transmittance T2 detected within this range satisfies the relationship 0.06≦(T0−T1) / (T0−T2)≦0.4.

[0035] In the IR spectrum obtained by measuring attenuated total reflection in Fourier transform infrared spectroscopy, -1 From 2400cm -1 The peak detected in the range is the peak of the carbonyl group derived from the isocyanate group, and -1 From 1700cm -1The peak detected in this range is the peak of the carbonyl group derived from the urethane bond. When the ratio of isocyanate groups to urethane bonds satisfies 0.06≦(T0-T1) / (T0-T2)≦0.4, the adhesive layer contains unreacted isocyanate groups and urea resins and biuret resins produced by the reaction of some of the curing agents. Due to the active hydrogen groups present in the urea resins and biuret resins, the tensile strength and elongation at break of the adhesive layer become closer to those of each layer (mainly the barrier layer and substrate), resulting in improved moldability. Furthermore, when the molded product of the present invention is exposed to a high-temperature environment (150°C), the reaction between unreacted curing agents is accelerated. The increase in urea resins and biuret resins increases the Tg of the adhesive layer, improving heat resistance.

[0036] In contrast, when (T0-T1) / (T0-T2)<0.06, two patterns exist: the base resin and curing agent react quantitatively under the condition of NCO / OH≒1.0, or the curing agents react quantitatively under the condition of NCO / OH>1.0. In the former case, the Tg of the adhesive layer drops significantly below that of a high-temperature environment (150°C), resulting in cohesive failure of the adhesive layer. In the latter case, almost all of the curing agent reacts during aging, resulting in an adhesive layer that is more brittle than one in which 0.06≦(T0-T1) / (T0-T2)≦0.4 is satisfied, resulting in a significant decrease in moldability.

[0037] Furthermore, when (T0-T1) / (T0-T2) > 0.4, there is an excess of unreacted curing agent in the adhesive layer. If this adhesive layer is exposed to a high-temperature environment, the excess curing agent may react with itself, causing foaming. This can lead to delamination in high-temperature environments, reducing heat resistance.

[0038] In the first adhesive layer 12a, the polyfunctional isocyanate compound may include, in addition to IPDI-nurate, at least one selected from the group consisting of an adduct of tolylene diisocyanate (TDI-adduct), an adduct of hexamethylene diisocyanate, a biuret and nurate of hexamethylene diisocyanate, a biuret and nurate of tolylene diisocyanate, an adduct, biuret and nurate of diphenylmethane diisocyanate, and an adduct, biuret and nurate of xylylene diisocyanate, or may include a TDI-adduct. Using such a polyfunctional isocyanate compound in combination with IPDI-nurate can further improve lamination strength and deep drawability at room temperature.

[0039] When the polyfunctional isocyanate compound contains a TDI-adduct, the ratio (NCOA / NCOB) of the number of isocyanate groups derived from IPDI-nurate (NCOA) to the number of isocyanate groups derived from the TDI-adduct (NCOB) may be 0.05 to 20. From the viewpoint of heat resistance, the ratio (NCOA / NCOB) may be 0.3 to 6, 2 to 4, or even 3. The ratio (NCOA / NCOB) may also be 7 to 20. When this ratio is 0.05 or more, sufficient laminate strength can be ensured in a high-temperature environment, and the occurrence of delamination when exposed to high temperatures after deep drawing can be sufficiently suppressed. When the ratio is 20 or less, laminate strength and deep drawing formability in a room-temperature environment can be further improved.

[0040] In the first adhesive layer 12a, the ratio (NCO / OH) of the number of isocyanate groups contained in the polyfunctional isocyanate compound to the number of hydroxyl groups contained in the polyester polyol resin may be 2 to 60, 5 to 50, or 10 to 30. When this ratio is 2 or more, the laminate strength in a high-temperature environment can be further improved. When the ratio is 60 or less, the laminate strength in a room temperature environment and a high-temperature environment can be further improved.

[0041] The thickness of the first adhesive layer 12a is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, conformability, processability, etc., it is preferably, for example, 1 to 10 μm, more preferably 3 to 7 μm.

[0042] The mass per unit area of ​​the first adhesive layer 12a is set to 2.0 to 6.0 g / m from the viewpoint of ensuring superior lamination strength both in a room temperature environment and a high temperature environment and obtaining superior deep drawability. 2 and 2.5 to 5.0 g / m 2 and may be 3.0 to 4.0 g / m 2 may be.

[0043] <Barrier layer 13> The barrier layer 13 has water vapor barrier properties that prevent moisture from penetrating into the interior of the electricity storage device. The barrier layer 13 also has extensibility for deep drawing. Examples of the barrier layer 13 that can be used include various metal foils such as aluminum, stainless steel, and copper, as well as metal vapor-deposited films, inorganic oxide vapor-deposited films, carbon-containing inorganic oxide vapor-deposited films, and films having these vapor-deposited films. Examples of films having vapor-deposited films that can be used include aluminum vapor-deposited films and inorganic oxide vapor-deposited films. These may be used alone or in combination of two or more. In terms of mass (specific gravity), moisture resistance, processability, and cost, metal foils are preferred for the barrier layer 13, and aluminum foil is more preferred.

[0044] As the aluminum foil, soft aluminum foil that has been annealed is particularly preferred because it can impart the desired ductility during molding. However, it is more preferable to use aluminum foil containing iron for the purpose of imparting further pinhole resistance and ductility during molding. The iron content in the aluminum foil is preferably 0.1 to 9.0 mass%, more preferably 0.5 to 2.0 mass%, based on 100 mass% of the aluminum foil. By having an iron content of 0.1 mass% or more, an exterior packaging material 10 having better pinhole resistance and ductility can be obtained. By having an iron content of 9.0 mass% or less, an exterior packaging material 10 having better flexibility can be obtained. As the aluminum foil, untreated aluminum foil may be used, but it is preferable to use aluminum foil that has been degreased to impart electrolyte resistance. When the aluminum foil is degreased, the degreasing treatment may be performed on only one side of the aluminum foil, or on both sides.

[0045] The thickness of the barrier layer 13 is not particularly limited, but is preferably 9 to 200 μm, more preferably 15 to 100 μm, taking into consideration barrier properties, pinhole resistance, and processability. If the thickness is thinner than 15 μm, moldability may decrease. If the thickness is thicker than 100 μm, the weight energy density of the battery tends to decrease and the cost will increase.

[0046] <First and second corrosion prevention treatment layers 14a, 14b> The first and second corrosion prevention treatment layers 14a and 14b are layers provided on the surface of the barrier layer 13 to prevent corrosion of the metal foil (metal foil layer) that constitutes the barrier layer 13. The first corrosion prevention treatment layer 14a serves to increase the adhesion between the barrier layer 13 and the first adhesive layer 12a. The second corrosion prevention treatment layer 14b serves to increase the adhesion between the barrier layer 13 and the second adhesive layer 12b. The first corrosion prevention treatment layer 14a and the second corrosion prevention treatment layer 14b may be layers of the same configuration or layers of different configurations. The first and second corrosion prevention treatment layers 14a and 14b (hereinafter simply referred to as "corrosion prevention treatment layers 14a and 14b") may be formed by, for example, degreasing treatment, hydrothermal conversion treatment, anodizing treatment, chemical conversion treatment, or a combination of these treatments.

[0047] Examples of degreasing treatments include acid degreasing and alkaline degreasing. Examples of acid degreasing include a method using an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, or hydrofluoric acid, either alone or in combination. Furthermore, by using an acid degreasing agent prepared by dissolving a fluorine-containing compound such as monosodium ammonium difluoride in the inorganic acid, not only can the aluminum be degreased, but also a passive aluminum fluoride can be formed, which is effective in terms of corrosion resistance, particularly when an aluminum foil is used for the barrier layer 13. Examples of alkaline degreasing include a method using sodium hydroxide or the like.

[0048] An example of the hydrothermal modification treatment is boehmite treatment, in which aluminum foil is immersed in boiling water containing triethanolamine.

[0049] An example of the anodizing treatment is alumite treatment.

[0050] The chemical conversion treatment may be an immersion type or a coating type. Examples of the immersion type chemical conversion treatment include chromate treatment, zirconium treatment, titanium treatment, vanadium treatment, molybdenum treatment, calcium phosphate treatment, strontium hydroxide treatment, cerium treatment, ruthenium treatment, and various chemical conversion treatments consisting of a mixture of these. On the other hand, an example of the coating type chemical conversion treatment is a method in which a coating agent having corrosion prevention properties is applied to the barrier layer 13.

[0051] When forming at least a part of the corrosion prevention treatment layer by any of these corrosion prevention treatments, i.e., hydrothermal conversion treatment, anodizing treatment, or chemical conversion treatment, it is preferable to perform the degreasing treatment described above beforehand. Note that when a degreased metal foil, such as a metal foil that has been subjected to an annealing process, is used as the barrier layer 13, there is no need to perform a degreasing treatment again when forming the corrosion prevention treatment layers 14a and 14b.

[0052] The coating agent used in the spray-type chemical conversion treatment preferably contains trivalent chromium and may also contain at least one polymer selected from the group consisting of cationic polymers and anionic polymers, which will be described later.

[0053] Among the above treatments, hydrothermal conversion treatment and anodizing, in particular, dissolve the aluminum foil surface with a treatment agent to form aluminum compounds (boehmite, anodized aluminum) with excellent corrosion resistance. Therefore, a bicontinuous structure is formed from the aluminum foil barrier layer 13 to the corrosion prevention treatment layers 14a, 14b, and these treatments are included in the definition of chemical conversion treatment. On the other hand, as described below, it is also possible to form the corrosion prevention treatment layers 14a, 14b using a pure coating method, which is not included in the definition of chemical conversion treatment. One example of such a method is the use of a sol of a rare earth oxide, such as cerium oxide, with an average particle size of 100 nm or less, which has an aluminum corrosion prevention effect (inhibitor effect) and is environmentally friendly. Using this method, it is possible to impart corrosion prevention effects to metal foils such as aluminum foil using a conventional coating method.

[0054] Examples of the rare earth element oxide sol include sols using various solvents such as water-based, alcohol-based, hydrocarbon-based, ketone-based, ester-based, ether-based, etc. Of these, water-based sols are preferred.

[0055] In order to stabilize the dispersion of the rare earth element oxide sol, inorganic acids such as nitric acid, hydrochloric acid, phosphoric acid, or their salts, or organic acids such as acetic acid, malic acid, ascorbic acid, and lactic acid are usually used as dispersion stabilizers. Of these dispersion stabilizers, phosphoric acid in particular is expected to have the following effects on the exterior packaging material 10: (1) stabilization of the sol dispersion, (2) improvement of adhesion to the barrier layer 13 by utilizing the aluminum chelating ability of phosphoric acid, and (3) improvement of the cohesion of the corrosion prevention treatment layers 14a, 14b (oxide layers) due to the tendency of phosphoric acid to undergo dehydration condensation even at low temperatures.

[0056] Examples of the phosphoric acid or its salt include orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, or their alkali metal salts or ammonium salts. Among these, condensed phosphoric acids such as trimetaphosphoric acid, tetrametaphosphoric acid, hexametaphosphoric acid, and ultrametaphosphoric acid, or their alkali metal salts or ammonium salts, are preferred for functional expression in the exterior packaging material 10. Furthermore, when considering the drying film-forming properties (drying capacity, heat quantity) when forming the corrosion prevention treatment layers 14a, 14b made of rare earth element oxides using the rare earth element oxide sol by various coating methods, sodium salts are more preferred because of their excellent dehydration condensation properties at low temperatures. Water-soluble salts are preferred as phosphates.

[0057] The compounding ratio of phosphoric acid (or a salt thereof) to rare earth element oxide is preferably 1 to 100 parts by mass per 100 parts by mass of rare earth element oxide. If the compounding ratio is 1 part by mass or more per 100 parts by mass of rare earth element oxide, the rare earth element oxide sol becomes more stable, and the functionality of the packaging material 10 becomes better. The compounding ratio is more preferably 5 parts by mass or more per 100 parts by mass of rare earth element oxide. Furthermore, if the compounding ratio is 100 parts by mass or less per 100 parts by mass of rare earth element oxide, the functionality of the rare earth element oxide sol is improved. The compounding ratio is more preferably 50 parts by mass or less, and even more preferably 20 parts by mass or less, per 100 parts by mass of rare earth element oxide.

[0058] Since the corrosion prevention treatment layers 14a, 14b formed from the rare earth element oxide sol are aggregates of inorganic particles, the cohesive strength of the layers themselves may be reduced even after the dry-cure process. Therefore, in this case, the corrosion prevention treatment layers 14a, 14b are preferably compounded with the following anionic polymer or cationic polymer to compensate for the cohesive strength.

[0059] Examples of anionic polymers include polymers having a carboxy group, such as poly(meth)acrylic acid (or a salt thereof) or a copolymer copolymerized with poly(meth)acrylic acid as the main component. The copolymerization components of this copolymer include alkyl(meth)acrylate monomers (alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, 2-ethylhexyl, and cyclohexyl groups); (meth)acrylamide, N-alkyl(meth)acrylamide, N,N-dialkyl(meth)acrylamide (alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, 2-ethylhexyl, and cyclohexyl groups); N-alkoxy(meth)acrylamide, N,N-dialkoxy(meth)acrylamide, and (alkoxy)acrylamide. Examples of the oxy group include a methoxy group, an ethoxy group, a butoxy group, and an isobutoxy group. Examples of the oxy group include amide group-containing monomers such as N-methylol(meth)acrylamide and N-phenyl(meth)acrylamide; hydroxyl group-containing monomers such as 2-hydroxyethyl(meth)acrylate and 2-hydroxypropyl(meth)acrylate; glycidyl group-containing monomers such as glycidyl(meth)acrylate and allyl glycidyl ether; silane-containing monomers such as (meth)acryloxypropyltrimethoxysilane and (meth)acryloxypropyltriethoxylane; and isocyanate group-containing monomers such as (meth)acryloxypropylisocyanate.

[0060] These anionic polymers improve the stability of the corrosion-resistant treated layers 14a, 14b (oxide layers) obtained using the rare earth element oxide sol. This is achieved by protecting the hard and brittle oxide layer with the acrylic resin component and by capturing ionic contaminants (especially sodium ions) derived from the phosphate contained in the rare earth element oxide sol (as a cation catcher). In other words, if the corrosion-resistant treated layers 14a, 14b obtained using the rare earth element oxide sol contain alkali metal ions, particularly sodium, or alkaline earth metal ions, the corrosion-resistant treated layers 14a, 14b are prone to degradation originating from the locations containing these ions. Therefore, by immobilizing the sodium ions and other ions contained in the rare earth element oxide sol using the anionic polymer, the durability of the corrosion-resistant treated layers 14a, 14b is improved.

[0061] The corrosion prevention treatment layers 14a, 14b, which combine anionic polymers and rare earth oxide sols, have corrosion prevention performance equivalent to that of corrosion prevention treatment layers 14a, 14b formed by chromate treatment of aluminum foil. The anionic polymer preferably has a structure in which an essentially water-soluble polyanionic polymer is crosslinked. Examples of crosslinking agents used to form this structure include compounds having an isocyanate group, a glycidyl group, a carboxyl group, or an oxazoline group.

[0062] Examples of compounds having an isocyanate group include diisocyanates such as tolylene diisocyanate, xylylene diisocyanate or hydrogenated products thereof, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate or hydrogenated products thereof, and isophorone diisocyanate; or polyisocyanates such as adducts obtained by reacting these isocyanates with polyhydric alcohols such as trimethylolpropane, biuret compounds obtained by reacting these isocyanates with water, or trimer isocyanurates; and blocked polyisocyanates obtained by blocking these polyisocyanates with alcohols, lactams, oximes, or the like.

[0063] Examples of compounds having a glycidyl group include epoxy compounds obtained by reacting epichlorohydrin with glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 14a,14b-butanediol, 1,6-hexanediol, and neopentyl glycol; epoxy compounds obtained by reacting epichlorohydrin with polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, and sorbitol; and epoxy compounds obtained by reacting epichlorohydrin with dicarboxylic acids such as phthalic acid, terephthalic acid, oxalic acid, and adipic acid.

[0064] Examples of compounds having a carboxy group include various aliphatic or aromatic dicarboxylic acids, etc. Poly(meth)acrylic acid and alkali (earth) metal salts of poly(meth)acrylic acid may also be used.

[0065] Examples of compounds having an oxazoline group include low molecular weight compounds having two or more oxazoline units, and when a polymerizable monomer such as isopropenyloxazoline is used, copolymers of acrylic monomers such as (meth)acrylic acid, alkyl (meth)acrylates, and hydroxyalkyl (meth)acrylates.

[0066] Alternatively, an anionic polymer may be reacted with a silane coupling agent, more specifically, by selectively reacting the carboxyl groups of the anionic polymer with the functional groups of the silane coupling agent to form siloxane bonds at the crosslinking points. In this case, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-chloropropylmethoxysilane, vinyltrichlorosilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, etc. may be used. Among these, epoxysilanes, aminosilanes, and isocyanatesilanes are preferred, especially in terms of reactivity with anionic polymers or their copolymers.

[0067] The ratio of these crosslinking agents to the anionic polymer is preferably 1 to 50 parts by mass, more preferably 10 to 20 parts by mass, per 100 parts by mass of the anionic polymer. When the ratio of the crosslinking agent is 1 part by mass or more per 100 parts by mass of the anionic polymer, a crosslinked structure is easily formed sufficiently. When the ratio of the crosslinking agent is 50 parts by mass or less per 100 parts by mass of the anionic polymer, the pot life of the coating liquid is improved.

[0068] The method for crosslinking the anionic polymer is not limited to the above-mentioned crosslinking agents, and may also be a method for forming ionic crosslinks using titanium or zirconium compounds.

[0069] Examples of cationic polymers include polymers containing amines, such as polyethyleneimine, ionic polymer complexes consisting of polyethyleneimine and a polymer containing carboxylic acid, primary amine-grafted acrylic resins in which a primary amine is grafted onto an acrylic backbone, polyallylamine or derivatives thereof, and cationic polymers such as aminophenol. Examples of polyallylamine include homopolymers or copolymers of allylamine, allylamine amide sulfate, diallylamine, and dimethylallylamine. These amines may be free amines or stabilized with acetic acid or hydrochloric acid. Furthermore, maleic acid, sulfur dioxide, and the like may be used as copolymer components. Furthermore, types in which the primary amine is partially methoxylated to impart thermal crosslinking properties can also be used, and aminophenols can also be used. Allylamine or its derivatives are particularly preferred.

[0070] The cationic polymer is preferably used in combination with a crosslinking agent having a functional group capable of reacting with amine / imine, such as a carboxy group or a glycidyl group. As the crosslinking agent to be used in combination with the cationic polymer, a polymer having a carboxylic acid that forms an ionic polymer complex with polyethyleneimine can also be used, and examples thereof include polycarboxylic acid (salts) such as polyacrylic acid or its ionic salts, copolymers thereof with comonomers introduced therein, and polysaccharides having a carboxy group, such as carboxymethylcellulose or its ionic salts.

[0071] Cationic polymers are more preferred materials in terms of improving adhesion. Furthermore, like the anionic polymers, cationic polymers are also water-soluble, so it is more preferred to form a crosslinked structure to impart water resistance. The crosslinking agent used to form the crosslinked structure in the cationic polymer can be the same as the crosslinking agent described in the anionic polymer section. When a rare earth element oxide sol is used as the corrosion prevention treatment layers 14a and 14b, a cationic polymer may be used as the protective layer instead of the anionic polymer.

[0072] A corrosion-preventing treatment layer formed by chemical conversion treatment, such as chromate treatment, is formed by treating aluminum foil with a chemical conversion treatment agent, particularly a combination of hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, or their salts, followed by the application of a chromium or non-chromium compound to form a chemical conversion treatment layer on the aluminum foil. However, since the above-mentioned chemical conversion treatment uses an acid in the chemical conversion treatment agent, it can lead to deterioration of the working environment and corrosion of the coating equipment. On the other hand, unlike chemical conversion treatments such as chromate treatment, the aforementioned coating-type corrosion-preventing treatment layers 14a and 14b do not require the formation of a gradient structure relative to the barrier layer 13 using aluminum foil. Therefore, the properties of the coating agent are not restricted by acidity, alkalinity, neutrality, etc., and a good working environment can be achieved. In addition, chromate treatments using chromium compounds are preferred because alternatives are needed for environmental hygiene reasons.

[0073] From the above, examples of combinations of the above-mentioned coating-type corrosion prevention treatments include (1) rare earth element oxide sol only, (2) anionic polymer only, (3) cationic polymer only, (4) rare earth element oxide sol + anionic polymer (laminated composite), (5) rare earth element oxide sol + cationic polymer (laminated composite), (6) (rare earth element oxide sol + anionic polymer: laminated composite) / cationic polymer (multilayered), and (7) (rare earth element oxide sol + cationic polymer: laminated composite) / anionic polymer (multilayered). Among these, (1) and (4) to (7) are preferred, and (4) to (7) are particularly preferred. However, this embodiment is not limited to the above combinations. For example, as an example of the selection of corrosion prevention treatment, cationic polymers are very preferable materials because they have good adhesion to the modified polyolefin resins mentioned in the description of the adhesive resin layer below. Therefore, when the adhesive resin layer is made of a modified polyolefin resin, it is possible to design the surface that comes into contact with the adhesive resin layer to have a cationic polymer (for example, structures (5) and (6)).

[0074] Furthermore, the corrosion prevention treatment layers 14a, 14b are not limited to the layers described above. For example, they may be formed using a treatment agent that combines phosphoric acid and a chromium compound with a resin binder (such as aminophenol), as in the case of a known paint-type chromate. Using this treatment agent makes it possible to obtain a layer that combines both corrosion prevention functionality and adhesion. Furthermore, although the stability of the coating liquid must be considered, a coating agent that combines a rare earth element oxide sol with a polycationic polymer or a polyanionic polymer in advance as a one-component can be used to obtain a layer that combines corrosion prevention functionality and adhesion.

[0075] The mass per unit area of ​​the corrosion prevention treatment layers 14a and 14b is 0.005 to 0.200 g / m 2 regardless of whether the layer has a multi-layer structure or a single-layer structure. 2 is preferable, and 0.010 to 0.100 g / m 2 It is more preferable that the mass per unit area is 0.005 g / m 2 If the mass per unit area is 0.200 g / m or more, it is easy to impart a corrosion prevention function to the barrier layer 13. 2 Even if the thickness exceeds this range, the corrosion prevention function does not change significantly. On the other hand, when a rare earth element oxide sol is used, if the coating is thick, the heat curing during drying may be insufficient, which may result in a decrease in cohesive force. The thickness of the corrosion prevention treatment layers 14a and 14b can be calculated from their specific gravity.

[0076] From the viewpoint of easily maintaining the adhesion between the sealant layer and the barrier layer, the corrosion prevention treatment layers 14a, 14b may be in an embodiment containing, for example, cerium oxide, 1 to 100 parts by mass of phosphoric acid or a phosphate salt per 100 parts by mass of the cerium oxide, and a cationic polymer, or may be formed by subjecting the barrier layer 13 to a chemical conversion treatment, or may be formed by subjecting the barrier layer 13 to a chemical conversion treatment and contain a cationic polymer.

[0077] <Second adhesive layer 12b> The second adhesive layer 12b is a layer that bonds the barrier layer 13, on which the second corrosion prevention treatment layer 14b is formed, to the sealant layer 16. A common adhesive for bonding a barrier layer to a sealant layer can be used for the second adhesive layer 12b. Specific examples of materials that constitute the second adhesive layer 12b include polyurethane resins in which a bifunctional or higher isocyanate compound is reacted with a base resin such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol.

[0078] The various polyols described above can be used alone or in combination of two or more types depending on the functions and performance required of the packaging material.

[0079] Depending on the performance required of the adhesive, various other additives and stabilizers may be blended into the polyurethane resin described above.

[0080] In the packaging material 10 of this embodiment, the second adhesive layer 12b may be the same as the above-described first adhesive layer 12a.

[0081] The thickness of the second adhesive layer 12b is not particularly limited, but is preferably 1 to 10 μm, more preferably 3 to 7 μm, from the viewpoint of obtaining the desired adhesive strength and processability.

[0082] When the second adhesive layer 12b is the same as the first adhesive layer 12a, the mass per unit area of ​​the second adhesive layer 12b is set to 2.0 to 6.0 g / m from the viewpoint of ensuring superior lamination strength both in a room temperature environment and a high temperature environment and obtaining superior deep drawability. 2 and 2.5 to 5.0 g / m 2 and 3.5 to 4.5 g / m 2 may be.

[0083] <Sealant layer 16> The sealant layer 16 is a layer that provides heat-sealing properties to the exterior packaging material 10. Examples of the sealant layer 16 include resin films made of polyolefin resins or polyester resins. These resins (hereinafter also referred to as "base resins") that constitute the sealant layer 16 may be used alone or in combination of two or more.

[0084] Examples of polyolefin resins include low-density, medium-density, or high-density polyethylene; ethylene-α-olefin copolymers; polypropylene; block or random copolymers containing propylene as a copolymerization component; and propylene-α-olefin copolymers.

[0085] Examples of polyester resins include polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polyethylene naphthalate (PEN) resin, polybutylene naphthalate (PBN) resin, and polytrimethylene terephthalate (PTT) resin.

[0086] The sealant layer 16 may contain a polyolefin-based elastomer. The polyolefin-based elastomer may be compatible or incompatible with the base resin described above, and may contain both a compatible polyolefin-based elastomer that is compatible with the base resin and an incompatible polyolefin-based elastomer that is incompatible with the base resin. "Compatible" means that the elastomer disperses in the base resin with a dispersed phase size of 1 nm or more and less than 500 nm. "Incompatible" means that the elastomer disperses in the base resin with a dispersed phase size of 500 nm or more and less than 20 μm.

[0087] When the base resin is a polypropylene resin, the compatible polyolefin elastomer may be, for example, a propylene-butene-1 random copolymer, and the incompatible polyolefin elastomer may be, for example, an ethylene-butene-1 random copolymer. The polyolefin elastomers may be used alone or in combination of two or more.

[0088] The sealant layer 16 may also contain additives such as slip agents, antiblocking agents, antioxidants, light stabilizers, and flame retardants. The content of these additives is preferably 5 parts by mass or less, assuming that the total mass of the sealant layer 16 is 100 parts by mass.

[0089] The thickness of the sealant layer 16 is not particularly limited, but from the viewpoint of achieving both a thin film and improved heat seal strength in a high-temperature environment, it is preferably in the range of 5 to 100 μm, more preferably in the range of 10 to 100 μm, and even more preferably in the range of 20 to 80 μm.

[0090] The sealant layer 16 may be either a single-layer film or a multi-layer film, and may be selected depending on the required function.

[0091] The above describes in detail a preferred embodiment of the exterior packaging material for a power storage device of this embodiment, but the present disclosure is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present disclosure as set forth in the claims.

[0092] For example, Figure 1 shows a case where corrosion prevention treatment layers 14a and 14b are provided on both sides of the barrier layer 13, but only one of the corrosion prevention treatment layers 14a and 14b may be provided, or no corrosion prevention treatment layer may be provided.

[0093] While Fig. 1 shows a case where the barrier layer 13 and the sealant layer 16 are laminated using the second adhesive layer 12b, the barrier layer 13 and the sealant layer 16 may be laminated using an adhesive resin layer 15, as in the packaging material 20 for an electricity storage device shown in Fig. 2. Furthermore, in the packaging material 20 for an electricity storage device shown in Fig. 2, the second adhesive layer 12b may be provided between the barrier layer 13 and the adhesive resin layer 15.

[0094] <Adhesive resin layer 15> The adhesive resin layer 15 is generally composed of an adhesive resin composition as a main component and additive components as necessary. The adhesive resin composition is not particularly limited, but preferably contains a modified polyolefin resin.

[0095] The modified polyolefin resin is preferably a polyolefin resin graft-modified with an unsaturated carboxylic acid derivative derived from an unsaturated carboxylic acid, or an acid anhydride or ester thereof.

[0096] Examples of polyolefin resins include low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-α-olefin copolymer, homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymer.

[0097] The modified polyolefin resin is preferably a polyolefin resin modified with maleic anhydride. Suitable modified polyolefin resins include, for example, "Admer" manufactured by Mitsui Chemicals, Inc. and "Modic" manufactured by Mitsubishi Chemical Corporation. Such modified polyolefin resins have excellent reactivity with various metals and polymers having various functional groups, and this reactivity can be utilized to impart adhesion to the adhesive resin layer 15 and improve electrolyte resistance. Furthermore, the adhesive resin layer 15 may contain various additives, such as compatible and incompatible elastomers, flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, and tackifiers, as needed.

[0098] The thickness of the adhesive resin layer 15 is not particularly limited, but is preferably the same as or smaller than that of the sealant layer 16 from the viewpoint of stress relaxation and water / electrolyte permeability.

[0099] In addition, in the packaging material 20 for a storage battery device, the total thickness of the adhesive resin layer 15 and the sealant layer 16 is preferably in the range of 5 to 100 μm, and more preferably in the range of 20 to 80 μm, from the viewpoint of achieving both a thin film and improved heat seal strength in a high-temperature environment.

[0100] [Exterior material manufacturing method] Next, a description will be given of an example of a method for manufacturing the packaging material 10 shown in Fig. 1. Note that the method for manufacturing the packaging material 10 is not limited to the following method.

[0101] The manufacturing method of the exterior material 10 of this embodiment is roughly composed of the steps of providing corrosion prevention treatment layers 14a, 14b on the barrier layer 13, bonding the base material layer 11 and the barrier layer 13 together using the first adhesive layer 12a, further laminating the sealant layer 16 via the second adhesive layer 12b to produce a laminate, and, if necessary, aging the obtained laminate.

[0102] (Step of Laminating Anti-Corrosion Treatment Layers 14a and 14b on Barrier Layer 13) This step is a step of forming corrosion prevention treatment layers 14a and 14b on the barrier layer 13. As described above, examples of the method for forming the corrosion prevention treatment layers 14a and 14b include degreasing treatment, hydrothermal treatment, anodizing treatment, and chemical conversion treatment on the barrier layer 13, and applying a coating agent having corrosion prevention properties.

[0103] Furthermore, when the corrosion prevention treatment layers 14a, 14b are multi-layered, for example, the coating liquid (coating agent) constituting the lower corrosion prevention treatment layer (barrier layer 13 side) may be applied to the barrier layer 13 and baked to form a first layer, and then the coating liquid (coating agent) constituting the upper corrosion prevention treatment layer may be applied to the first layer and baked to form a second layer.

[0104] Degreasing treatment can be performed by spraying or immersion. Hydrothermal conversion treatment and anodizing treatment can be performed by immersion. Chemical conversion treatment can be performed by immersion, spraying, coating, or other methods appropriately selected depending on the type of chemical conversion treatment.

[0105] As a method for applying a coating agent having corrosion prevention properties, various methods such as gravure coating, reverse coating, roll coating, and bar coating can be used.

[0106] As described above, the various treatments may be applied to either one or both sides of the metal foil, but in the case of one-side treatment, the treated side is preferably the side on which the sealant layer 16 is laminated. If desired, the above treatments may also be applied to the surface of the base layer 11.

[0107] The amount of coating agent applied to form the first layer and the second layer is 0.005 to 0.200 g / m 2 is preferable, and 0.010 to 0.100 g / m 2 is more preferred.

[0108] Furthermore, if dry curing is required, it can be carried out at a base material temperature in the range of 60 to 300° C. depending on the drying conditions of the corrosion prevention treatment layers 14a and 14b used.

[0109] (Step of bonding the base layer 11 and the barrier layer 13) This step is a step of bonding the barrier layer 13 provided with the corrosion prevention treatment layers 14a and 14b to the base material layer 11 via the first adhesive layer 12a. The bonding method may be dry lamination, non-solvent lamination, wet lamination, or the like, and the two are bonded together using the material that constitutes the first adhesive layer 12a described above. The first adhesive layer 12a has a dry coating amount of 1 to 10 g / m. 2 range, more preferably 2 to 6 g / m 2 It is set within the range.

[0110] (Laminating step of second adhesive layer 12b and sealant layer 16) This step is a step of bonding the sealant layer 16 via the second adhesive layer 12b to the second corrosion prevention treatment layer 14b side of the barrier layer 13. Examples of bonding methods include a wet process and dry lamination.

[0111] In the case of a wet process, a solution or dispersion of the adhesive constituting the second adhesive layer 12b is applied onto the second corrosion prevention treatment layer 14b, and the solvent is evaporated at a predetermined temperature to form a dry film, or a baking process is performed as necessary after the dry film formation. The sealant layer 16 is then laminated to produce the exterior material 10. Examples of application methods include the various application methods exemplified above. The preferred dry application amount of the second adhesive layer 12b is the same as that of the first adhesive layer 12a.

[0112] In this case, the sealant layer 16 can be produced, for example, by a melt extrusion molding machine using a resin composition for forming a sealant layer containing the above-mentioned components of the sealant layer 16. From the viewpoint of productivity, the processing speed of the melt extrusion molding machine can be set to 80 m / min or more.

[0113] (Aging treatment process) This step is a step of aging (curing) the laminate. By aging the laminate, it is possible to promote adhesion between the barrier layer 13, the second corrosion prevention treatment layer 14b, the second adhesive layer 12b, and the sealant layer 16. The aging treatment can be carried out at a temperature ranging from room temperature to 100°C. The aging time is, for example, 1 to 10 days.

[0114] In this manner, the packaging material 10 of this embodiment as shown in FIG. 1 can be manufactured.

[0115] Next, a description will be given of an example of a method for manufacturing the exterior packaging material 20 shown in Fig. 2. Note that the method for manufacturing the exterior packaging material 20 is not limited to the following method.

[0116] The manufacturing method of the packaging material 20 of this embodiment is generally composed of the steps of providing corrosion prevention treatment layers 14a, 14b on the barrier layer 13, bonding the base material layer 11 and the barrier layer 13 together using the first adhesive layer 12a, further laminating the adhesive resin layer 15 and the sealant layer 16 to prepare a laminate, and, if necessary, heat treating the obtained laminate. Note that the steps up to the step of bonding the base material layer 11 and the barrier layer 13 can be carried out in the same manner as the manufacturing method of the packaging material 10 described above.

[0117] (Laminating Step of Adhesive Resin Layer 15 and Sealant Layer 16) This step is a step of forming an adhesive resin layer 15 and a sealant layer 16 on the second corrosion prevention treatment layer 14b formed in the previous step. Examples of methods include sand lamination of the adhesive resin layer 15 together with the sealant layer 16 using an extrusion laminator. Furthermore, lamination can also be performed using a tandem lamination method or a co-extrusion method in which the adhesive resin layer 15 and the sealant layer 16 are extruded. When forming the adhesive resin layer 15 and the sealant layer 16, for example, the components are blended so as to satisfy the above-described structures of the adhesive resin layer 15 and the sealant layer 16. The above-described resin composition for forming a sealant layer is used to form the sealant layer 16.

[0118] This process produces a laminate in which the layers are stacked in the following order: base layer 11 / first adhesive layer 12a / first corrosion prevention treatment layer 14a / barrier layer 13 / second corrosion prevention treatment layer 14b / adhesive resin layer 15 / sealant layer 16, as shown in Figure 2.

[0119] The adhesive resin layer 15 may be formed by directly extruding dry-blended materials having the above-described material composition using an extrusion laminator. Alternatively, the adhesive resin layer 15 may be formed by extruding granules obtained by previously melt-blending the materials using a melt-kneading device such as a single-screw extruder, a twin-screw extruder, or a Brabender mixer, and then extruding the granules using an extrusion laminator.

[0120] The sealant layer 16 may be formed by directly extruding materials dry-blended to the composition described above as the constituent components of the resin composition for forming a sealant layer using an extrusion laminator. Alternatively, the adhesive resin layer 15 and the sealant layer 16 may be formed by a tandem lamination method in which the granules obtained by melt-blending the resin composition using a melt-kneading device such as a single-screw extruder, a twin-screw extruder, or a Brabender mixer are extruded into the adhesive resin layer 15 and the sealant layer 16 using an extrusion laminator, or by a co-extrusion method. Alternatively, a sealant monolayer may be formed in advance as a cast film using the resin composition for forming a sealant layer, and this film may be laminated together with an adhesive resin by sand lamination. The formation speed (processing speed) of the adhesive resin layer 15 and the sealant layer 16 may be, for example, 80 m / min or more from the viewpoint of productivity.

[0121] (Heat treatment process) This step is a step of heat-treating the laminate. Heat-treating the laminate can improve adhesion between the barrier layer 13, the second corrosion prevention treatment layer 14b, the adhesive resin layer 15, and the sealant layer 16. As a method of heat treatment, it is preferable to treat at a temperature at least equal to or higher than the melting point of the adhesive resin layer 15.

[0122] In this manner, the exterior packaging material 20 of this embodiment as shown in FIG. 2 can be manufactured.

[0123] The above describes in detail preferred embodiments of the exterior packaging material for a power storage device of the present disclosure, but the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present disclosure as set forth in the claims.

[0124] The packaging material for an electricity storage device according to the present disclosure can be suitably used as a packaging material for an electricity storage device such as a secondary battery such as a lithium ion battery, a nickel-metal hydride battery, or a lead-acid battery, and an electrochemical capacitor such as an electric double layer capacitor. In particular, the packaging material for an electricity storage device according to the present disclosure is suitable as a packaging material for an all-solid-state battery using a solid electrolyte.

[0125] [Electricity storage device] FIG. 3 is a perspective view showing one embodiment of an electricity storage device fabricated using the above-described exterior material. As shown in FIG. 3, the electricity storage device 50 includes a battery element (electricity storage device main body) 52, two metal terminals (current extraction terminals) 53 for extracting current from the battery element 52 to the outside, and an exterior material 10 that hermetically encases the battery element 52. The exterior material 10 is the exterior material 10 according to the present embodiment described above. In the exterior material 10, the base material layer 11 is the outermost layer, and the sealant layer 16 is the innermost layer. That is, the exterior material 10 is configured to encase the battery element 52 by folding one laminate film in half and heat-sealing it, or by overlapping and heat-sealing two laminate films, so that the base material layer 11 is on the exterior side of the electricity storage device 50 and the sealant layer 16 is on the interior side of the electricity storage device 50. Note that the electricity storage device 50 may use an exterior material 20 instead of the exterior material 10.

[0126] Battery element 52 has an electrolyte interposed between a positive electrode and a negative electrode. Metal terminal 53 is a part of the current collector that is taken out from exterior packaging 10, and is made of metal foil such as copper foil or aluminum foil.

[0127] The electricity storage device 50 of this embodiment may be an all-solid-state battery. In this case, a solid electrolyte such as a sulfide-based solid electrolyte is used as the electrolyte of the battery element 52. The electricity storage device 50 of this embodiment uses the packaging material 10 of this embodiment, and therefore can ensure excellent laminate strength even when used in a high-temperature environment. [Example]

[0128] Hereinafter, the present disclosure will be described more specifically based on examples, but the present disclosure is not limited to the following examples.

[0129] [Materials used] The materials used in the examples and comparative examples are shown below.

[0130] <Base layer (thickness 25 μm)> Ny: A nylon (Ny) film (manufactured by Toyobo Co., Ltd.) was used, one side of which was subjected to a corona treatment. PET: A polyethylene terephthalate film with one side subjected to corona treatment was used.

[0131] <First adhesive layer> The first adhesive was prepared by blending the base resin and curing agent shown in Table 1 so that the NCO / OH ratio was as shown in the table, and diluting with ethyl acetate to a solid content of 26% by mass. When two types of curing agents were used, they were mixed so that the proportion of NCO groups in each curing agent relative to the total NCO groups in the curing agent was as shown in Table 1. Details of each component that makes up the first adhesive are as follows: (Main ingredient) Polyether polyol (AGC Corporation, product name: EXCENOL, product number: 837, hydroxyl value: 27 mg KOH / g) Polyester polyol (Hitachi Chemical Co., Ltd., product name: Teslac 2505-63, hydroxyl value: 7-11 mgKOH / g) Acrylic polyol (manufactured by Taisei Fine Chemical Co., Ltd., product name: 6KW-700, hydroxyl value: 10 mg KOH / g) Polycarbonate diol (PCD) (manufactured by Asahi Kasei Corporation, product name: Duranol T5651, hydroxyl value: 113 mg KOH / g) (hardening agent) IPDI-n: Isophorone diisocyanate nurate (Mitsui Chemicals, product name: Takenate 600) HDI-a: Hexamethylene diisocyanate adduct (manufactured by Asahi Kasei Corporation, product name: Duranate P301-75E) MDI polymer: Diphenylmethane diisocyanate polymer (manufactured by Tosoh Corporation, product name: Coronate 139) TDI-a: Tolylene diisocyanate adduct (Mitsui Chemicals, product name: Takenate 500)

[0132] <First corrosion prevention treatment layer (base layer side) and second corrosion prevention treatment layer (sealant layer side)> (CL-1): "Sodium polyphosphate-stabilized cerium oxide sol" was used, adjusted to a solids concentration of 10% by mass using distilled water as the solvent. The sodium polyphosphate-stabilized cerium oxide sol was obtained by blending 100 parts by mass of cerium oxide with 10 parts by mass of sodium phosphate. (CL-2): A composition consisting of 90% by mass of "polyallylamine (manufactured by Nitto Boseki Co., Ltd.)" adjusted to a solid content concentration of 5% by mass using distilled water as a solvent and 10% by mass of "polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation)" was used.

[0133] <Barrier layer (thickness 40 μm)> Either annealed and degreased soft aluminum foil (manufactured by Toyo Aluminum Co., Ltd., "8079 material") or copper foil (manufactured by JX Metals Corporation, model number: HA) was used.

[0134] <Second adhesive layer (coating amount 3g / m 2 )> The polyurethane adhesive was prepared by blending polyisocyanate with acid-modified polyolefin dissolved in a mixed solvent of toluene and methylcyclohexane.

[0135] <Sealant layer (thickness 80 μm)> A polyolefin film (a non-stretched polypropylene film with the surface of the second adhesive layer side corona-treated) was used.

[0136] [Fabrication of exterior materials] Example 1 The barrier layer (aluminum foil) was attached to the base layer (nylon) using a first adhesive (first adhesive layer) by dry lamination. The barrier layer and base layer were laminated by applying the first adhesive to one side of the barrier layer so that the applied amount (mass per unit area) after drying was the value shown in Table 1, drying at 80°C for 1 minute, laminating it with the base layer, and aging it at 80°C for 120 hours.

[0137] Next, the surface of the barrier layer opposite the substrate layer side was attached to a sealant layer (thickness 80 μm) using a polyurethane adhesive (second adhesive layer) by dry lamination. The lamination of the barrier layer and sealant layer was performed by applying a polyurethane adhesive to the surface of the barrier layer opposite the substrate layer side in an amount (mass per unit area) of 3 g / m after drying. 2 The coating was applied so that the coating would become as shown in the figure, and the coating was dried at 80°C for 1 minute, followed by laminating the coating with a sealant layer and aging for 3 hours at 120°C. Using the above method, an exterior material (a laminate of base material layer / first adhesive layer / barrier layer / second adhesive layer / sealant layer) was produced.

[0138] (Examples 2 to 17) Except for changing at least one of the composition of the first adhesive and the amount of application of the first adhesive as shown in Table 1, the exterior materials of Examples 2 to 17 (laminates of substrate layer / first adhesive layer / barrier layer / second adhesive layer / sealant layer) were prepared in the same manner as in Example 1.

[0139] Example 18 The packaging material of Example 18 (a laminate of base material layer / first adhesive layer / barrier layer / second adhesive layer / sealant layer) was produced in the same manner as Example 1, except that the material of the barrier layer was copper foil (Cu) and the composition of the first adhesive and the amount of the first adhesive applied were changed as shown in Table 1.

[0140] (Examples 19 to 21) Except for using aluminum foil as the barrier layer and changing its thickness as shown in Table 1, the packaging materials of Examples 19 to 21 (laminates of base material layer / first adhesive layer / barrier layer / second adhesive layer / sealant layer) were produced in the same manner as in Example 18.

[0141] Example 22 An exterior material of Example 22 (a laminate of substrate layer / first adhesive layer / barrier layer / second adhesive layer / sealant layer) was produced in the same configuration as Example 16, except that the corrosion prevention layer was not provided on the barrier layer.

[0142] Example 23 An exterior material of Example 23 (a laminate of substrate layer / first adhesive layer / barrier layer / second adhesive layer / sealant layer) was produced in the same configuration as Example 16, except that the substrate was made of PET.

[0143] (Comparative Examples 1 and 2) Except for changing the composition of the first adhesive as shown in Table 1, the exterior materials of Comparative Examples 1 and 2 (laminates of substrate layer / first adhesive layer / barrier layer / second adhesive layer / sealant layer) were produced in the same manner as in Example 1.

[0144] [IR measurement] The exterior material was cut to an appropriate size, and a trigger was created at the edge to peel the base layer and the barrier layer. When measuring the attenuated total reflection (ATR) of the Fourier transform infrared (FT-IR) spectroscopy from the surface of the base layer and the barrier layer where more adhesive layer remained, the infrared wave number was measured at a transmittance of 2200 cm from the baseline transmittance T0. -1 From 2300cm -1 The minimum transmittance T1 detected in the range of 1670cm -1 From 1710cm -1 The minimum transmittance T2 detected within this range was calculated. Each calculated value was evaluated to see if it satisfied the relationship 0.06≦(T0-T1) / (T0-T2)≦0.4. The results are shown in Table 1. <Measurement conditions> Prism: Germanium Wavenumber resolution: 4cm -1 Number of times accumulated: 4 times Baseline: Wavenumber 2500-2700cm -1 The average intensity between <Measuring equipment> PerkinElmer: Spectrum Spotlight 400

[0145] [Table 1]

[0146] [Evaluation of the strength of the heat-resistant laminate on the exterior side] The barrier layer and base layer of the exterior material cut to a width of 15 mm were peeled off. Measurements were performed using a 90-degree peel tester (manufactured by Shimadzu Corporation) at a pulling speed of 50 mm / min. In the following evaluations, a rating of △ or higher was considered to be a pass. (Laminate strength at room temperature) The laminate strength was measured under a room temperature (25°C) environment. The laminate strength was evaluated according to the following criteria. The results are shown in Table 2. ◎: Laminate strength is 6.0N / 15mm or more. Good: Laminate strength is 4.5N / 15mm or more and less than 6.0N / 15mm. △: Laminate strength is 3.0N / 15mm or more and less than 4.5N / 15mm. ×: Laminate strength is less than 3.0N / 15mm.

[0147] (Laminate strength in high temperature environments) The exterior material was cut to a width of 15 mm and left in a high-temperature environment at 150°C for 5 minutes. After that, the laminate strength was measured in the 150°C environment. The obtained laminate strength was evaluated according to the following criteria. The results are shown in Table 2. ◎: Laminate strength is 3.5N / 15mm or more. Good: Laminate strength is 2.5N / 15mm or more and less than 3.5N / 15mm. △: Laminate strength is 2.0N / 15mm or more and less than 2.5N / 15mm. ×: Laminate strength is less than 2.0N / 15mm.

[0148] [Evaluation of deep drawing formability] The molding depth at which deep drawing was possible for exterior packaging materials was evaluated using the following method. The molding depth of the molding machine was set to 1.00 to 5.00 mm in 0.25 mm increments, and the exterior packaging materials were deep-draw molded. After deep drawing, the samples were visually inspected for the presence of breaks and pinholes while shining a light on them, and the maximum molding depth at which deep drawing was possible without the occurrence of breaks or pinholes was determined. The molding depth was also evaluated according to the following criteria. The results are shown in Table 2. ◎: Maximum molding depth is 5.00 mm or more. 〇: The maximum molding depth is 4.00 mm or more and less than 5.00 mm. △: The maximum molding depth is 3.00 mm or more and less than 4.00 mm. ×: The maximum molding depth is less than 3.00 mm.

[0149] [Evaluation of deep drawing reliability] The samples (five specimens each) with a mold depth of 2.00 mm prepared for the deep drawability evaluation were stored in a 150°C environment for one week. After that, the samples were visually inspected while shining a light on the vicinity of the molded convex portion to check for the occurrence of delamination between the base layer and the barrier layer. The environmental reliability was also evaluated according to the following criteria. The results are shown in Table 2. ○: Delamination did not occur in any of the five samples. ×: Delamination occurred in one or more of the five samples.

[0150] [Table 2] [Industrial Applicability]

[0151] According to the present disclosure, an exterior material for a power storage device that can ensure excellent laminate strength both in room temperature environments and high temperature environments and also has excellent deep draw formability, and a power storage device using the same are provided. [Explanation of symbols]

[0152] DESCRIPTION OF SYMBOLS 10, 20... Power storage device packaging material, 11... Base material layer, 12a... First adhesive layer, 12b... Second adhesive layer, 13... Barrier layer, 14a... First corrosion prevention treatment layer, 14b... Second corrosion prevention treatment layer, 15... Adhesive resin layer, 16... Sealant layer, 50... Power storage device, 52... Battery element, 53... Metal terminal

Claims

1. a laminate including at least a base layer, a first adhesive layer, a barrier layer, a second adhesive layer, and a sealant layer in this order; the first adhesive layer contains a urethane resin formed from a polyester polyol and two types of polyfunctional isocyanate compounds, namely, an alicyclic isocyanate polymer and an isocyanate polymer containing an aromatic ring in its molecular structure; The base material layer is removed to expose the first adhesive layer, and when measured by attenuated total reflection of Fourier transform infrared spectroscopy from the outermost surface side of the exposed first adhesive layer, the baseline transmittance T0 and the transmittance at 2100 cm －１ From 2400 cm －１ The minimum transmittance T1 detected in the range of 1670 cm －１ From 1700 cm －１ The minimum transmittance T2 detected in the range satisfies the relationship 0.06≦(T0−T1) / (T0−T2)≦0.

4.

2. The exterior material for an all-solid-state battery according to claim 1, wherein the ratio of the number of isocyanate groups contained in the polyfunctional isocyanate compound to the number of hydroxyl groups contained in the polyester polyol is 5 to 60.

3. The all-solid-state battery exterior packaging material according to claim 1 or 2, wherein the alicyclic isocyanate polymer is a nurate of isophorone diisocyanate.

4. The all-solid-state battery exterior material according to any one of claims 1 to 3, wherein the isocyanate polymer containing an aromatic ring is an adduct of tolylene diisocyanate.

5. the alicyclic isocyanate polymer is a nurate of isophorone diisocyanate and the aromatic ring-containing isocyanate polymer is an adduct of tolylene diisocyanate; 3. The all-solid-state battery according to claim 1, wherein the ratio NCOA / NCOB of the number of isocyanate groups NCOA derived from the nurate form of isocyanate to the number of isocyanate groups NCOB derived from the adduct of tolylene diisocyanate is 2 to 4. The outer casing material for all-solid-state batteries according to claim 1 or 2.

6. The exterior material for an all-solid-state battery according to claim 1, wherein the amount of the urethane resin applied after drying is 2.0 g / m 2 or more and 6.0 g / m 2 or less.

7. The all-solid-state battery exterior material according to claim 1, wherein the barrier layer is an aluminum foil or a stainless steel foil.

8. The all-solid-state battery exterior material according to claim 1, wherein the barrier layer has a thickness of 15 to 100 μm.

9. The exterior material for an all-solid-state battery according to any one of claims 1 to 8, having a corrosion prevention treatment layer at least either between the first adhesive layer and the barrier layer or between the second adhesive layer and the barrier layer.

10. The all-solid-state battery exterior material according to claim 1, wherein the substrate layer is made of a polyamide film or a polyester film.

11. An all-solid-state battery body; a current extraction terminal extending from the all-solid-state battery body; The all-solid-state battery exterior packaging material according to any one of claims 1 to 10, which holds the current extracting terminal and houses the all-solid-state battery body; An all-solid-state battery comprising:

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