Battery packaging materials and batteries

Abstract

The present invention provides a battery packaging material that is excellent in formability and is made of a laminate that includes at least a base layer, a barrier layer, and a heat-sealable resin layer in this order. The battery packaging material of the present invention is composed of a laminate including at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, The thickness of the laminate is 100 μm or less, The laminate is subjected to a tensile test under the following test conditions, and the breaking energy per unit width of 1 m calculated from a curve of measured load (N / 15 mm) vs. displacement measured thereon is such that the sum X+Y of the breaking energy X in one direction perpendicular to the thickness direction of the laminate and the breaking energy Y in another direction perpendicular to both the one direction and the thickness direction of the laminate is 200 J or more. (Test conditions) Test speed: 50 mm / min Test piece width: 15 mm Gauge distance: 30mm

Description

[Technical Field]

[0001] The present invention relates to a packaging material for a battery and a battery. [Background technology]

[0002] Various types of batteries have been developed, but packaging materials are essential components for all batteries to seal battery elements such as electrodes and electrolytes. Conventionally, metal packaging materials have been widely used for battery packaging.

[0003] Meanwhile, in recent years, with the increasing performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., batteries are being required to have a variety of shapes as well as to be thinner and lighter in weight. However, the metal battery packaging materials that have been widely used up until now have the drawbacks of being difficult to accommodate the diversification of shapes and also having limitations on how light they can be made.

[0004] Therefore, in recent years, a film-like laminate in which a base material layer, a barrier layer, and a heat-sealable resin layer are laminated in this order has been proposed as a packaging material for batteries that can be easily processed into various shapes and can be made thinner and lighter (see, for example, Patent Document 1).

[0005] In such battery packaging materials, recesses are generally formed by cold forming, battery elements such as electrodes and electrolyte are placed in the spaces formed by the recesses, and the heat-sealable resin layers are heat-sealed to obtain a battery in which the battery elements are housed inside the battery packaging material. However, such film-like packaging materials are thinner than metal packaging materials and have the disadvantage of being prone to pinholes and cracks during molding. If pinholes or cracks occur in the battery packaging material, the electrolyte may penetrate into the barrier layer and form metal precipitates, which may result in a short circuit. Therefore, it is essential that film-like battery packaging materials have the property of being less prone to pinholes and the like during molding, i.e., excellent moldability. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-287971 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, with the demand for smaller and thinner batteries, there has been a demand for even thinner battery packaging materials. However, when the thickness of a battery packaging material made of the above-mentioned film-like laminate is extremely thin, for example, 100 μm or less, cracks and pinholes tend to occur during molding, making it difficult to impart high moldability.

[0008] A primary object of the present invention is to provide a battery packaging material that is excellent in formability and that is made of a laminate having at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order. [Means for solving the problem]

[0009] The present inventors conducted extensive research to solve the above-mentioned problems. As a result, they found that a battery packaging material comprising a laminate including at least a base layer, a barrier layer, and a heat-sealable resin layer in this order can have excellent moldability when the thickness of the laminate is 100 μm or less, and when a tensile test of the laminate is performed under the following test conditions, the breaking energy per unit width meter calculated from the curve of "measured load (N / 15 mm) - displacement" measured is 200 J or more. The breaking energy X in one direction perpendicular to the thickness direction of the laminate and the breaking energy Y in another direction perpendicular to both the one direction and the thickness direction of the laminate are calculated from the curve of "measured load (N / 15 mm) - displacement." The present invention was completed based on these findings and through further research. (Test conditions) Test speed: 50 mm / min Test piece width: 15 mm Gauge distance: 30mm The length of the test piece shall be 100 mm. However, if only a test piece shorter than 100 mm in length is available, the test piece shall be as long as possible (as close to 100 mm as possible) as long as the gauge length can be secured and both ends of the test piece can be grasped during measurement.

[0010] That is, the present invention provides a battery packaging material and a battery according to the following aspects. Item 1. The laminate is composed of at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, The thickness of the laminate is 100 μm or less, The laminate is subjected to a tensile test under the following test conditions, and the breaking energy per unit width of 1 m is calculated from a curve of measured load (N / 15 mm) vs. displacement, where X is the breaking energy in one direction perpendicular to the thickness direction of the laminate, and Y is the breaking energy in another direction perpendicular to both the one direction and the thickness direction of the laminate, and the sum X+Y of these is 200 J or more. (Test conditions) Test speed: 50 mm / min Test piece width: 15 mm Gauge distance: 30mm Item 2. The battery packaging material according to Item 1, wherein the one direction is the MD of the laminate and the other direction is the TD of the laminate. Item 3. The battery packaging material according to Item 1 or 2, wherein the laminate has a puncture strength of 15 N or more when measured from the base layer side by a method conforming to the provisions of JIS Z1707:1995. Item 4. The battery packaging material according to any one of Items 1 to 3, further comprising an adhesive layer between the base material layer and the barrier layer. Item 5. The battery packaging material according to Item 4, wherein the adhesive layer contains a colorant. Item 6. The battery packaging material according to Item 4 or 5, further comprising a colored layer between the base material layer and the adhesive layer. Item 7. The battery packaging material according to any one of Items 1 to 6, further comprising a surface coating layer on the opposite side of the substrate layer from the barrier layer. Item 8. A battery, in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed from the battery packaging material according to any one of Items 1 to 7. [Effects of the Invention]

[0011] According to the present invention, in a battery packaging material comprising a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order, despite the thickness of the laminate being as very thin as 100 μm or less, with respect to the breaking energy per unit width of 1 m calculated from the curve of "measured load (N / 15 mm) - displacement" measured when a tensile test is performed on the laminate under the test conditions described above, the sum X+Y of the breaking energy X in one direction perpendicular to the thickness direction of the laminate and the breaking energy Y in another direction perpendicular to both the one direction and the thickness direction of the laminate is 200 J or more, and therefore a battery packaging material with excellent formability can be provided. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing an example of a cross-sectional structure of a battery packaging material of the present invention. [Figure 2] 1 is a diagram showing an example of a cross-sectional structure of a battery packaging material of the present invention. [Figure 3] 1 is a diagram showing an example of a cross-sectional structure of a battery packaging material of the present invention. [Figure 4] 1 is a diagram showing an example of a cross-sectional structure of a battery packaging material of the present invention. [Figure 5] 1 is a diagram showing an example of a cross-sectional structure of a battery packaging material of the present invention. [Figure 6] 10 is a curve of measured load (N / 15 mm) vs. displacement (MD) obtained in a tensile test of the battery packaging material of Example 5. [Figure 7] FIG. 1 is a schematic diagram showing a portion where data on a curve of measured load (N / 15 mm) versus displacement amount is integrated. [Figure 8] FIG. 2 is a schematic diagram for explaining a method for evaluating curling due to molding of a battery packaging material. [Figure 9]FIG. 2 is a schematic diagram for explaining a method for evaluating curling due to molding of a battery packaging material. [Figure 10] FIG. 2 is a schematic diagram of a barrier layer of a test sample after molding in an example. DETAILED DESCRIPTION OF THE INVENTION

[0013] The battery packaging material of the present invention is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order, the thickness of the laminate being 100 μm or less, and the laminate being characterized in that, with respect to the breaking energy per unit width of 1 m calculated from the curve of measured load (N / 15 mm) vs. displacement measured when performing a tensile test under the following test conditions, the total X+Y of the breaking energy X in one direction perpendicular to the thickness direction of the laminate and the breaking energy Y in another direction perpendicular to both the one direction and the thickness direction of the laminate is 200 J or more. The battery packaging material of the present invention will be described in detail below. (Test conditions) Test speed: 50 mm / min Test piece width: 15 mm Gauge distance: 30mm

[0014] In this specification, a numerical range indicated by "to" means "greater than or equal to" or "less than or equal to." For example, the expression 2 to 15 mm means 2 mm or greater and 15 mm or less.

[0015] 1.Layer structure and physical properties of battery packaging materials 1 to 5, the battery packaging material of the present invention is composed of a laminate in which at least a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4 are laminated in this order. In the battery packaging material of the present invention, the base material layer 1 is the outermost layer, and the heat-sealable resin layer 4 is the innermost layer. That is, when assembling a battery, the heat-sealable resin layers 4 located on the periphery of the battery element are heat-sealed to each other to seal the battery element, thereby sealing the battery element.

[0016] As shown in Figures 2 to 5, the battery packaging material of the present invention may optionally include an adhesive layer 2 between the base material layer 1 and the barrier layer 3 to enhance adhesion therebetween. As shown in Figures 3 to 5, the battery packaging material of the present invention may optionally include an adhesive layer 5 between the barrier layer 3 and the heat-sealable resin layer 4 to enhance adhesion therebetween. As shown in Figures 4 and 5, a surface coating layer 6 may optionally be provided on the outer side of the base material layer 1 (the side opposite to the heat-sealable resin layer 4). As shown in Figure 5, a colored layer 7 may optionally be provided between the base material layer 1 and the adhesive layer 2.

[0017] The laminate constituting the battery packaging material of the present invention has a thickness of 100 μm or less, and with respect to the breaking energy per unit width of 1 m calculated from the curve of "measurement load (N / 15 mm) - displacement" measured when a tensile test is performed under the above test conditions, the total X+Y of the breaking energy X in one direction perpendicular to the thickness direction of the laminate (i.e., the stacking direction of the laminate) and the breaking energy Y in another direction perpendicular to both the one direction and the thickness direction of the laminate (i.e., the other direction is perpendicular to the one direction and also perpendicular to the thickness direction of the laminate) is 200 J or more. From the viewpoint of further improving formability while reducing the thickness of the battery packaging material, it is preferable that the one direction is the machine direction (MD) of the laminate and the other direction is the transverse direction (TD) of the laminate. That is, with regard to the breaking energy per unit width 1 m calculated from the curve of "measurement load (N / 15 mm) - displacement" measured when a tensile test is carried out under the above test conditions, it is preferable that the sum X+Y of the breaking energy X in MD, which is the machine direction of the laminate, and the breaking energy Y in TD, which is the perpendicular direction, is 200 J or more. In the present invention, the tensile test means a test of tensile properties.

[0018] Furthermore, from the viewpoint of improving formability while reducing the thickness of the battery packaging material, the upper limit of the total breaking energy X+Y is preferably about 700 J or less, about 500 J or less, about 495 J or less, about 450 J or less, about 445 J or less, about 400 J or less, less than about 400 J, or about 380 J, and the lower limit is preferably about 250 J or more, more preferably about 300 J or more. The range of the total breaking energy X+Y is preferably about 200 to 700 J, about 200 to 500 J, about 200 to 495 J, about 200 to 450 J, about 200 to 445 J, about 200 to 400 J, about 200 J or more but less than about 400 J, about 200 to 380 J, about 250 to 700 J, about 250 to 500 J, about 250 to 495 ... to 380 J, about 250 to 700 J, about 25 Examples include approximately 50 to 450J, approximately 250 to 445J, approximately 250 to 400J, approximately 250J or more but less than approximately 400J, approximately 250 to 380J, approximately 300 to 700J, approximately 300 to 500J, approximately 300 to 495J, approximately 300 to 450J, approximately 300 to 445J, approximately 300 to 400J, approximately 300J or more but less than approximately 400J, and approximately 300 to 380J.

[0019] A method for achieving a total breaking energy X+Y of 200 J or greater involves adjusting the materials and thicknesses of the substrate layer, barrier layer, and heat-sealable resin layer that make up the laminate. The substrate layer is an example of the layer that contributes most to the magnitude of the breaking energy. Materials described below are used for the substrate layer, and during the manufacturing process of the substrate layer, the type of film-forming method and film-forming conditions (e.g., film-forming temperature, stretching ratio, cooling temperature, cooling rate, and heat-setting temperature after stretching) are appropriately adjusted. Examples of film-forming methods include the T-die method, calendaring method, and tubular method. Furthermore, in order to achieve a total breaking energy X+Y of 200 J or greater, it is preferable to heat the laminate at an appropriate temperature and for an appropriate time during the heating process after laminating the layers. By adopting an appropriate temperature and time, it is possible to improve the adhesion of each layer while suppressing damage to the laminate, particularly to the substrate layer. The upper limit of the heating temperature in the heating step is preferably about 185°C or less, more preferably about 180°C or less, and even more preferably 178°C or less. The lower limit of the heating temperature is preferably 150°C or more, more preferably 160°C or more, and even more preferably 165°C or more. Preferred ranges of the heating temperature in the heating step include about 150 to 185°C, about 150 to 180°C, about 150 to 178°C, about 160 to 185°C, about 160 to 180°C, about 160 to 178°C, about 165 to 185°C, about 160 to 180°C, and about 160 to 178°C. The upper limit of the heating time in the heating step is preferably 30 minutes or less, more preferably 15 minutes or less, and even more preferably 10 minutes or less. The lower limit is preferably 0.1 minutes or more, more preferably 0.5 minutes or more, and even more preferably 1 minute or more. It is preferable to combine the heating temperature and heating time in the heating step from among these.

[0020] In battery packaging materials, the MD and TD of the barrier layer described below can usually be determined during the manufacturing process. For example, when the barrier layer is made of aluminum foil, linear lines called rolling marks are formed on the surface of the aluminum foil in the rolling direction (RD) of the aluminum foil. Since the rolling marks extend along the rolling direction, the rolling direction of the aluminum foil can be determined by observing the surface of the aluminum foil. Furthermore, during the manufacturing process of a laminate, the MD of the laminate usually coincides with the RD of the aluminum foil, so the MD of the laminate can be identified by observing the surface of the aluminum foil of the laminate and identifying the rolling direction (RD) of the aluminum foil. Furthermore, since the TD of the laminate is perpendicular to the MD of the laminate, the TD of the laminate can also be identified.

[0021] In the present invention, the breaking energies X and Y per meter of width in the one direction and the other direction of the laminate constituting the battery packaging material are calculated by acquiring data on the measured load (N / 15 mm)-displacement curve measured when a tensile test is performed under the test conditions for each of the one direction and the other direction of the laminate, saving the data in a CSV file format, and integrating the data until the laminate breaks using spreadsheet software (Microsoft Excel (registered trademark)). The data is then converted (divided by 0.015) into the breaking energy per meter of width for each battery packaging material. The breaking energy X and Y per meter of width in the one direction and the breaking energy Y per meter of width in the other direction are then summed. Note that the time when the laminate breaks refers to the time when the test piece breaks. Five battery packaging materials are prepared for each test, and the breaking energy of the laminate is calculated by averaging the three breaking energy values, excluding the maximum and minimum values, for the five samples. Even if five samples cannot be prepared, it is preferable to use the average of the measurements of the number of samples that can be measured. In addition, a commercially available tensile tester can be used for the tensile test.

[0022] Furthermore, from the viewpoint of improving formability while reducing the thickness of the battery packaging material, the laminate constituting the battery packaging material of the present invention has a puncture strength measured from the base layer 1 side by a method conforming to the provisions of JIS Z1707:1995. The lower limit is preferably about 15 N or more, more preferably about 18 N or more, and even more preferably about 19 N or more, and the upper limit is preferably about 30 N or less, more preferably about 25 N or less, and even more preferably about 22 N or less. The puncture strength range is preferably about 15 to 30 N, about 15 to 25 N, about 18 to 30 N, about 18 to 25 N, about 18 to 22 N, about 19 to 30 N, about 19 to 25 N, or about 19 to 22 N. From the viewpoint of suppressing curling during molding of the battery packaging material, the puncture strength is preferably about 22 N or less. The puncture strength of the laminate is measured as follows.

[0023] <Puncture strength of laminate> The puncture strength of the laminate constituting the battery packaging material from the base layer side is measured according to the method specified in JIS Z1707:1995. Specifically, in a measurement environment of 23±2°C and relative humidity (50±5%), a test specimen is fixed using a 115mm diameter table with a 15mm central opening and a pressure plate, and a semicircular needle with a 1.0mm diameter and a 0.5mm tip radius is pierced at a rate of 50±5mm per minute, and the maximum stress until the needle penetrates is measured. Five test specimens are measured, and their average value is calculated. If there are not enough test specimens to measure five, the remaining number are measured and their average value is calculated.

[0024] The wet tension on the base layer 1 side of the laminate constituting the battery packaging material of the present invention is not particularly limited, but is preferably about 30 to 60 mN / m from the viewpoint of improving formability while reducing the thickness of the battery packaging material. Methods for adjusting the wet tension include adjusting the amount of lubricant present on the surface on the base layer 1 side, and subjecting the surface on the base layer 1 side to surface treatment (corona treatment, etc.). The wet tension is measured as follows.

[0025] <Wetting tension measurement> Using a wetting reagent conforming to JIS standards, the wetting tension on the base layer side of the laminate constituting the battery packaging material is measured. The test method conforms to JIS K6768:1999. Using a mixture for wetting tension testing, the reagent soaked in a cotton swab is applied 6 cm over the surface of the base layer side constituting the battery packaging material. 2 A line of about 100g is applied, and the test is judged by whether the liquid film breaks after 2 seconds. If the liquid film does not break, proceed to the mixed liquid with the next highest surface tension, and if it does break, proceed to the mixed liquid with the next lowest surface tension. Repeat this process to select a mixed liquid that can wet the surface of the test piece in 2 seconds. Wetting tension measurements are performed in an environment of 23°C and 50% relative humidity.

[0026] Furthermore, the battery packaging material of the present invention has a molding depth at which the barrier layer 3 described below has a thickness of 20 μm (i.e., the molding depth at which the barrier layer 3 of the battery packaging material has a thickness of 20 μm when the battery packaging material of the present invention is subjected to molding) of preferably 4.5 mm or more, more preferably 5.0 mm or more, and preferably 10.0 mm or less, more preferably 8.0 mm or less, with preferred ranges being about 4.5 to 10.0 mm, about 4.5 to 8.0 mm, about 5.0 to 10.0 mm, and about 5.0 to 8.0 mm. Specifically, the molding depth is a value measured by the method described in the Examples.

[0027] The critical forming depth of the battery packaging material of the present invention is preferably 4.0 mm or more, more preferably 5.5 mm or more, and is preferably 12.0 mm or less, more preferably 10.0 mm or less, with preferred ranges being about 4.0 to 12.0 mm, about 4.0 to 10.0 mm, about 5.5 to 12.0 mm, and about 5.5 to 10.0 mm. Specifically, the critical forming depth is a value measured by the method described in the Examples.

[0028] The thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited as long as it is 100 μm or less. However, from the viewpoint of ensuring excellent formability while making the thickness as thin as possible, the upper limit is preferably about 95 μm or less, more preferably about 89 μm or less, and even more preferably about 75 μm or less, and the lower limit is preferably about 35 μm or more, more preferably about 45 μm or more. Furthermore, the thickness range of the laminate is preferably about 35 to 100 μm, about 35 to 95 μm, about 45 to 95 μm, about 35 to 89 μm, about 45 to 89 μm, about 35 to 75 μm, or about 45 to 75 μm. Even though the thickness of the laminate constituting the battery packaging material of the present invention is as thin as 100 μm or less, excellent formability can be exhibited according to the present invention. Therefore, the battery packaging material of the present invention can contribute to improving the energy density of batteries.

[0029] 2. Layers that form the battery packaging material [Base material layer 1] In the battery packaging material of the present invention, the base material layer 1 is the layer located on the outermost layer side. The material forming the base material layer 1 is not particularly limited as long as it has insulating properties. Examples of materials forming the base material layer 1 include polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, phenolic resin, polyetherimide, polyimide, polycarbonate, and mixtures and copolymers thereof.

[0030] Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymer polyesters whose repeating units are mainly ethylene terephthalate, copolymer polyesters whose repeating units are mainly butylene terephthalate, etc. Specific examples of copolymer polyesters whose repeating units are mainly ethylene terephthalate include copolymer polyesters in which ethylene terephthalate is the main repeating unit and is polymerized with ethylene isophthalate (hereinafter abbreviated as polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decanedicarboxylate), etc. Specific examples of copolymer polyesters containing butylene terephthalate as the main repeating unit include copolymer polyesters in which butylene terephthalate is the main repeating unit and is polymerized with butylene isophthalate (hereinafter abbreviated as polybutylene(terephthalate / isophthalate)), polybutylene(terephthalate / adipate), polybutylene(terephthalate / sebacate), polybutylene(terephthalate / decanedicarboxylate), polybutylene naphthalate, etc. These polyesters may be used alone or in combination of two or more. Polyesters have the advantages of excellent electrolyte resistance and being less likely to cause whitening or other problems when exposed to an electrolyte, and are therefore preferably used as materials for forming the base layer 1.

[0031] Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (where I represents isophthalic acid and T represents terephthalic acid) containing structural units derived from terephthalic acid and / or isophthalic acid; aromatic polyamides such as polymetaxylylene adipamide (MXD6); alicyclic polyamides such as polyaminomethylcyclohexyl adipamide (PACM6); polyamides copolymerized with lactam components or isocyanate components such as 4,4'-diphenylmethane diisocyanate; polyesteramide copolymers and polyetheresteramide copolymers, which are copolymers of copolymerized polyamides with polyesters or polyalkylene ether glycols; and copolymers thereof. These polyamides may be used alone or in combination of two or more. A stretched polyamide film has excellent stretchability and can prevent whitening due to resin cracking in the base layer 1 during molding, and is therefore suitably used as a material for forming the base layer 1.

[0032] The substrate layer 1 may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, especially a biaxially stretched resin film, has improved heat resistance due to oriented crystallization, and is therefore preferably used as the substrate layer 1. Alternatively, the substrate layer 1 may be formed by coating the above-mentioned material on the barrier layer 3.

[0033] Among these, the resin film forming the base layer 1 is preferably nylon or polyester, more preferably biaxially oriented nylon or biaxially oriented polyester, and particularly preferably biaxially oriented nylon.

[0034] The base layer 1 can be laminated (multilayered) with at least one of resin films and coatings made of different materials to improve pinhole resistance and insulation when used as a battery package. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated together, a multilayer structure in which multiple nylon films are laminated together, and a multilayer structure in which multiple polyester films are laminated together. When the base layer 1 has a multilayer structure, a laminate of a biaxially oriented nylon film and a biaxially oriented polyester film, a laminate of multiple biaxially oriented nylon films, or a laminate of multiple biaxially oriented polyester films is preferred. Specific examples include a laminate of two biaxially oriented nylon films. Furthermore, because biaxially oriented polyester is less likely to discolor when an electrolyte solution adheres to its surface, when the base layer 1 has a multilayer structure in which a biaxially oriented nylon film and a biaxially oriented polyester film are laminated together, the base layer 1 is preferably a laminate having, in this order from the barrier layer 3 side. When the base layer 1 has a multi-layer structure, the thickness of each layer is preferably about 3 to 25 μm.

[0035] When the base material layer 1 has a multilayer structure, the resin films may be bonded via an adhesive, or may be directly laminated without an adhesive. When bonding without an adhesive, examples include methods of bonding in a hot-melt state, such as co-extrusion, sandwich lamination, and thermal lamination. When bonding via an adhesive, the adhesive used may be a two-component curing adhesive or a one-component curing adhesive. Furthermore, the adhesive mechanism is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot-melt type, a thermocompression type, an ultraviolet curing type, and an electron beam curing type. Specific examples of adhesives include those similar to those exemplified for the adhesive layer 2. The thickness of the adhesive may also be the same as that of the adhesive layer 2.

[0036] In the present invention, from the viewpoint of improving the formability of the battery packaging material, it is preferable that a lubricant be attached to the surface of the base layer 1. The lubricant is not particularly limited, but preferably an amide-based lubricant is used. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, and unsaturated fatty acid bisamides. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. Specific examples of methylol amides include methylol stearic acid amide. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipamide, and N,N'-distearyl sebacic acid amide. Specific examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide. Specific examples of fatty acid ester amides include stearamidoethyl stearate. Specific examples of aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N,N'-distearylisophthalic acid amide, etc. The lubricants may be used singly or in combination of two or more.

[0037] The content of the lubricant in the base layer 1 is not particularly limited, but from the viewpoint of improving the formability and insulating properties of the electronic packaging material, it is preferably about 0.01 to 0.2 mass %, more preferably about 0.05 to 0.15 mass %.

[0038] From the viewpoint of obtaining a battery packaging material with excellent formability while reducing the thickness of the battery packaging material, the thickness of the base material layer 1 preferably has a lower limit of about 8 μm or more, more preferably about 10 μm or more, and an upper limit of about 25 μm or less, more preferably about 20 μm or less. The thickness of the base material layer 1 preferably ranges from about 8 to 25 μm, about 8 to 20 μm, about 10 to 25 μm, or about 10 to 20 μm. In the present invention, when the base material layer 1 has a multilayer structure bonded with an adhesive, the thickness of the base material layer 1 does not include the thickness of the adhesive.

[0039] [Adhesive layer 2] In the battery packaging material of the present invention, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 in order to firmly bond them together.

[0040] The adhesive layer 2 is formed from an adhesive capable of bonding the base material layer 1 and the barrier layer 3. The adhesive used to form the adhesive layer 2 may be a two-component curing adhesive or a one-component curing adhesive. Furthermore, the adhesion mechanism of the adhesive used to form the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot pressure type, or the like.

[0041] Specific examples of adhesive components that can be used to form the adhesive layer 2 include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymer polyesters; polyether-based adhesives; polyurethane-based adhesives; epoxy-based resins; phenol-based resins; polyamide-based resins such as nylon 6, nylon 66, nylon 12, and copolymer polyamides; polyolefin-based resins such as polyolefins, carboxylic acid-modified polyolefins, and metal-modified polyolefins; polyvinyl acetate-based resins; cellulose-based adhesives; (meth)acrylic resins; polyimide-based resins; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone-based resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, polyurethane-based adhesives are preferred.

[0042] The adhesive layer 2 may also contain a colorant. When the adhesive layer 2 contains a colorant, the battery packaging material can be colored. Known colorants such as pigments and dyes can be used. Only one type of colorant may be used, or two or more types may be mixed together.

[0043] For example, specific examples of inorganic pigments include carbon black and titanium oxide. Specific examples of organic pigments include azo pigments, phthalocyanine pigments, and condensed polycyclic pigments. Examples of azo pigments include soluble pigments such as Watching Red and Carmine 6C; insoluble azo pigments such as monoazo yellow, disazo yellow, pyrazolone orange, pyrazolone red, and permanent red. Examples of phthalocyanine pigments include copper phthalocyanine pigments and metal-free phthalocyanine pigments such as blue and green pigments. Examples of condensed polycyclic pigments include dioxazine violet and quinacridone violet. Examples of pigments that can be used include pearl pigments and fluorescent pigments.

[0044] Among colorants, carbon black is preferred in order to give the battery packaging material a black appearance, for example.

[0045] The average particle size of the pigment is not particularly limited and may be, for example, about 0.05 to 5 μm, and preferably about 0.08 to 2 μm. The average particle size of the pigment is the median size measured with a laser diffraction / scattering particle size distribution measuring device.

[0046] The content of the pigment in the adhesive layer 2 is not particularly limited as long as it colors the battery packaging material, and may be, for example, about 5 to 60 mass %.

[0047] The thickness of the adhesive layer 2 is not particularly limited as long as it functions as an adhesive layer, but may be, for example, about 1 to 10 μm, and preferably about 2 to 5 μm.

[0048] [Colored layer 7] The colored layer 7 is a layer that is provided as needed between the base material layer 1 and the adhesive layer 2. By providing the colored layer 7, the battery packaging material can be colored.

[0049] The colored layer 7 can be formed, for example, by applying ink containing a colorant to the surface of the base layer 1. Known colorants such as pigments and dyes can be used as the colorant. Furthermore, only one type of colorant may be used, or two or more types may be mixed together.

[0050] Specific examples of the colorant contained in the colored layer 7 include the same as those exemplified in the section [Adhesive layer 2].

[0051] The ink for forming the colored layer 7 is not particularly limited, and any known ink can be used. Specific examples of the ink include ink containing a colorant, diamine, polyol, and curing agent. The solvent contained in the ink may be any known solvent, such as toluene.

[0052] The diamine is not particularly limited, and examples thereof include ethylenediamine, dimer diamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, dicyclohexylmethanediamine, 2-hydroxyethylpropylenediamine, etc. Among these, it is preferable to use one or more diamines selected from the group consisting of ethylenediamine, dimer diamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, and dicyclohexylmethanediamine as the diamine.

[0053] Diamines react with curing agents (such as isocyanates) faster than polyols, allowing for faster curing. Diamines react with the curing agent together with the polyol, accelerating the crosslinking and curing of the ink.

[0054] The polyol is not particularly limited, but it is preferable to use one or more polyols selected from the group consisting of polyurethane polyols, polyester polyols, and polyether polyols.

[0055] The number average molecular weight of the polyol is preferably in the range of about 1000 to 8000. When it is 1000 or more, the adhesive strength after curing can be increased, and when it is 8000 or less, the reaction rate with the curing agent can be increased.

[0056] The curing agent is not particularly limited, but examples thereof include isocyanate compounds. Examples of isocyanate compounds that can be used include various aromatic, aliphatic, and alicyclic isocyanate compounds. Specific examples include toluene diisocyanate (TDI), diphenylmethane diisocyanate, hexamethylene diisocyanate (HDI), and isophorone diisocyanate.

[0057] The content of the colorant in the colored layer 7 is not particularly limited as long as it can color the battery packaging material, and may be, for example, about 5 to 60 mass %. For example, when the colorant is carbon black, the content of carbon black is preferably about 20 to 50 mass %. The total content of the diamine, polyol, and curing agent is preferably about 40 to 85 mass %. The amount of curing agent is preferably about 2 to 20 mass parts per 100 mass parts of the total amount of the colorant, diamine, and polyol.

[0058] The thickness (after drying) of the colored layer 7 is preferably about 1 to 4 μm. When the thickness is 1 μm or more, the color tone of the colored layer 7 does not remain transparent, and the color and gloss of the barrier layer 3 can be sufficiently concealed. Furthermore, when the thickness is 4 μm or less, partial cracking of the colored layer 7 during molding can be sufficiently prevented.

[0059] The colored layer 7 can be formed, for example, by applying ink for forming the colored layer 7 to the surface of the base material layer 1. Examples of methods for applying the ink include printing methods such as gravure printing, reverse roll coating, and lip roll coating.

[0060] [Barrier layer 3] In the battery packaging material, the barrier layer 3 is a layer that not only improves the strength of the battery packaging material but also has the function of preventing water vapor, oxygen, light, and the like from penetrating into the battery. The barrier layer 3 is preferably a metal layer, i.e., a layer formed from a metal. Specific examples of metals that constitute the barrier layer 3 include aluminum, stainless steel, and titanium, with aluminum being preferred. The barrier layer 3 can be formed, for example, from a metal foil, a metal vapor-deposited film, an inorganic oxide vapor-deposited film, a carbon-containing inorganic oxide vapor-deposited film, or a film provided with any of these vapor-deposited films. It is preferably formed from a metal foil, and more preferably from an aluminum foil or stainless steel foil.

[0061] When the barrier layer 3 is made of aluminum foil, the aluminum foil is made of an aluminum alloy. From the viewpoint of preventing wrinkles and pinholes from occurring in the barrier layer 3 during the production of the battery packaging material, the barrier layer is more preferably made of soft aluminum foil such as annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O).

[0062] Furthermore, when the barrier layer 3 is composed of stainless steel foil, the stainless steel foil is preferably composed of austenitic stainless steel. This results in a battery packaging material with high puncture strength, excellent electrolyte resistance, and formability. Specific examples of austenitic stainless steel include SUS304, SUS301, and SUS316L, with SUS304 being particularly preferred. Furthermore, cold rolling of stainless steel foil improves its ductility and formability. Furthermore, heat treatment and annealing after cold rolling improve the balance between the flow direction and the width direction, improving formability. Furthermore, to stabilize the effects of the chemical conversion treatment described below, it is important to include a surface cleaning process after rolling or heat treatment. Examples of cleaning methods include washing with alkali or acid, and even alkaline electrolytic degreasing. Ultrasonic treatment or plasma treatment can also be used in combination. Alkaline degreasing or alkaline electrolytic degreasing is preferred. These methods improve the surface wettability, uniformity of the chemical conversion treatment, and stable resistance to contents.

[0063] The thickness of the barrier layer 3 is not particularly limited as long as it functions as a barrier layer against water vapor, etc., but is preferably about 50 μm or less, more preferably about 10 to 50 μm, and even more preferably about 10 to 40 μm.

[0064] Furthermore, it is preferable that at least one surface, and preferably both surfaces, of the barrier layer 3 be chemically treated to stabilize adhesion and prevent dissolution and corrosion. Here, chemical conversion treatment refers to a treatment for forming an acid-resistant film on the surface of the barrier layer. Examples of chemical conversion treatments include chromate treatments using chromium compounds such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromate acetylacetate, chromium chloride, and potassium chromium sulfate; phosphate treatments using phosphate compounds such as sodium phosphate, potassium phosphate, ammonium phosphate, and polyphosphoric acid; and chemical conversion treatments using aminated phenol polymers having repeating units represented by the following general formulas (1) to (4). The aminated phenol polymers may contain one type of repeating unit represented by the following general formulas (1) to (4) alone or in any combination of two or more types.

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] In the general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group, or a benzyl group. 1 and R 2 are the same or different and represent a hydroxy group, an alkyl group, or a hydroxyalkyl group. 1 and R 2Examples of the alkyl group represented by X include a linear or branched alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. 1 and R 2 Examples of the hydroxyalkyl group represented by the formula (1) include linear or branched alkyl groups having 1 to 4 carbon atoms and substituted with one hydroxy group, such as a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, and a 4-hydroxybutyl group. 1 and R 2 The alkyl groups and hydroxyalkyl groups represented by the formulas (1) to (4) may be the same or different. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group, or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having repeating units represented by the general formulas (1) to (4) is preferably, for example, about 500 to 1,000,000, and more preferably about 1,000 to 20,000.

[0070] Another example of a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3 is to coat the surface of the barrier layer 3 with fine particles of a metal oxide (e.g., aluminum oxide, titanium oxide, cerium oxide, or tin oxide) or barium sulfate dispersed in phosphoric acid, followed by baking at 150°C or higher to form a corrosion-resistant layer on the surface of the barrier layer 3. A resin layer in which a cationic polymer is crosslinked with a crosslinking agent may be further formed on the corrosion-resistant layer. Examples of cationic polymers include polyethyleneimine, ionic polymer complexes composed of a polymer having polyethyleneimine and a carboxylic acid, primary amine-grafted acrylic resins in which a primary amine is graft-polymerized onto an acrylic main skeleton, polyallylamine or its derivatives, and aminophenol. These cationic polymers may be used alone or in combination of two or more. Examples of crosslinking agents include compounds having at least one functional group selected from the group consisting of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and silane coupling agents. These crosslinking agents may be used alone or in combination of two or more.

[0071] Another example of a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3 is to coat the surface of the barrier layer 3 with a dispersion of fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, or barium sulfate, in phosphoric acid, followed by baking at 150°C or higher to form an acid-resistant coating on the surface of the barrier layer 3. A resin layer in which a cationic polymer is crosslinked with a crosslinking agent may be further formed on the acid-resistant coating. Examples of cationic polymers include polyethyleneimine, ionic polymer complexes composed of a polymer having polyethyleneimine and a carboxylic acid, primary amine-grafted acrylic resins in which a primary amine is graft-polymerized onto an acrylic main skeleton, polyallylamine or its derivatives, and aminophenol. These cationic polymers may be used alone or in combination of two or more. Examples of crosslinking agents include compounds having at least one functional group selected from the group consisting of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and silane coupling agents. These crosslinking agents may be used alone or in combination of two or more.

[0072] As a specific method for providing an acid-resistant coating, for example, at least the inner layer surface of the aluminum foil is first degreased by a well-known treatment method such as alkali immersion, electrolytic cleaning, acid pickling, electrolytic acid pickling, or acid activation, and then the degreased surface is coated with a treatment liquid (aqueous solution) mainly composed of a metal phosphate such as chromium phosphate, titanium phosphate, zirconium phosphate, or zinc phosphate, or a mixture of these metal salts, or a treatment liquid (aqueous solution) mainly composed of a non-metal phosphate and a mixture of these non-metal salts, or a treatment liquid (aqueous solution) consisting of a mixture of these with a water-based synthetic resin such as an acrylic resin, a phenolic resin, or a urethane resin, by a well-known coating method such as roll coating, gravure printing, or dipping, to form an acid-resistant coating. For example, when treated with a chromium phosphate treatment solution, an acid-resistant coating film made of chromium phosphate, aluminum phosphate, aluminum oxide, aluminum hydroxide, aluminum fluoride, etc. is formed, and when treated with a zinc phosphate treatment solution, an acid-resistant coating film made of zinc phosphate hydrate, aluminum phosphate, aluminum oxide, aluminum hydroxide, aluminum fluoride, etc. is formed.

[0073] Another example of a specific method for providing an acid-resistant coating is to first degrease at least the inner layer surface of the aluminum foil using a known treatment method such as alkali immersion, electrolytic cleaning, acid pickling, electrolytic pickling, or acid activation, and then subject the degreased surface to a known anodizing treatment, thereby forming an acid-resistant coating.

[0074] Other examples of acid-resistant coatings include phosphate-based and chromate-based coatings. Phosphate-based coatings include zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, and chromium phosphate, while chromate-based coatings include chromium chromate.

[0075] Other examples of acid-resistant coatings include those made from phosphates, chromates, fluorides, and triazine thiol compounds. These coatings prevent delamination between the aluminum and the base layer during embossing, and prevent dissolution and corrosion of the aluminum surface, particularly of aluminum oxide present on the surface, due to hydrogen fluoride produced by the reaction of electrolytes with water. They also improve the adhesion (wettability) of the aluminum surface, preventing delamination between the base layer and aluminum during heat sealing and, in the case of embossed types, during press molding. Among the substances that form acid-resistant coatings, an aqueous solution composed of three components—phenolic resin, chromium (III) fluoride compound, and phosphoric acid—is effective when applied to the aluminum surface and then dried and baked.

[0076] The acid-resistant coating may include a layer having cerium oxide, phosphoric acid or a phosphate, an anionic polymer, and a crosslinking agent that crosslinks the anionic polymer, and the phosphoric acid or phosphate may be blended in an amount of about 1 to 100 parts by mass per 100 parts by mass of the cerium oxide. Preferably, the acid-resistant coating has a multilayer structure that further includes a layer having a cationic polymer and a crosslinking agent that crosslinks the cationic polymer.

[0077] Furthermore, the anionic polymer is preferably poly(meth)acrylic acid or a salt thereof, or a copolymer mainly composed of (meth)acrylic acid or a salt thereof. Furthermore, the crosslinking agent is preferably at least one selected from the group consisting of a compound having any one of a functional group of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent.

[0078] The phosphoric acid or phosphate is preferably a condensed phosphoric acid or a condensed phosphate.

[0079] The chemical conversion treatment may be performed using only one type of chemical conversion treatment, or two or more types of chemical conversion treatments in combination. Furthermore, these chemical conversion treatments may be performed using one type of compound alone, or two or more types of compounds in combination. Among chemical conversion treatments, chromate treatments and chemical conversion treatments combining a chromium compound, a phosphate compound, and an aminated phenol polymer are preferred. Among chromium compounds, chromic acid compounds are preferred.

[0080] Specific examples of acid-resistant coatings include those containing at least one of phosphate, chromate, fluoride, and triazine thiol. Acid-resistant coatings containing a cerium compound are also preferred. The cerium compound is preferably cerium oxide.

[0081] Specific examples of acid-resistant coatings include phosphate-based coatings, chromate-based coatings, fluoride-based coatings, and triazine thiol compound coatings. The acid-resistant coating may be one of these, or a combination of two or more. Furthermore, the acid-resistant coating may be formed after degreasing the chemically treated surface of the aluminum foil, using a treatment solution consisting of a mixture of a metal phosphate and an aqueous synthetic resin, or a treatment solution consisting of a mixture of a non-metal phosphate and an aqueous synthetic resin.

[0082] The composition of the acid-resistant coating can be analyzed by, for example, time-of-flight secondary ion mass spectrometry. Analysis of the composition of the acid-resistant coating using time-of-flight secondary ion mass spectrometry can reveal, for example, Ce + and Cr + A peak derived from at least one of the above is detected.

[0083] The surface of the aluminum foil is preferably provided with an acid-resistant coating containing at least one element selected from the group consisting of phosphorus, chromium, and cerium. The presence of at least one element selected from the group consisting of phosphorus, chromium, and cerium in the acid-resistant coating on the surface of the aluminum foil of the battery packaging material can be confirmed using X-ray photoelectron spectroscopy. Specifically, first, the heat-sealable resin layer, adhesive layer, etc., laminated on the aluminum foil of the battery packaging material are physically peeled off. Next, the aluminum foil is placed in an electric furnace and heated at approximately 300°C for approximately 30 minutes to remove organic components present on the surface of the aluminum foil. The presence of these elements is then confirmed using X-ray photoelectron spectroscopy of the surface of the aluminum foil.

[0084] The amount of the acid-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited. For example, in the case of the above-mentioned chromate treatment, the amount of the acid-resistant film formed on the surface of the barrier layer 3 is 2 It is desirable that the chromium compound is contained in an amount of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, calculated as chromium, the phosphorus compound is contained in an amount of about 0.5 to 50 mg, preferably about 1.0 to 40 mg, calculated as phosphorus, and the aminated phenol polymer is contained in an amount of about 1.0 to 200 mg, preferably about 5.0 to 150 mg, calculated as phosphorus, per unit area.

[0085] The thickness of the acid-resistant coating is not particularly limited, but is preferably about 1 nm to 10 μm, more preferably about 1 to 100 nm, and even more preferably about 1 to 50 nm, from the viewpoint of the cohesive strength of the coating and the adhesive strength with the aluminum foil or the heat-sealable resin layer. The thickness of the acid-resistant coating can be measured by observation with a transmission electron microscope, or by a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy.

[0086] The chemical conversion treatment is carried out by applying a solution containing a compound used to form the acid-resistant coating to the surface of the barrier layer by bar coating, roll coating, gravure coating, immersion, or other methods, and then heating the barrier layer to a temperature of about 70 to 200°C. Before the chemical conversion treatment is carried out on the barrier layer, the barrier layer may be subjected to a degreasing treatment using an alkali immersion method, electrolytic cleaning, acid cleaning, electrolytic acid cleaning, or other methods. By carrying out such a degreasing treatment, the chemical conversion treatment on the surface of the barrier layer can be carried out more efficiently.

[0087] [Thermofusible resin layer 4] In the battery packaging material of the present invention, the heat-sealable resin layer 4 corresponds to the innermost layer, and is a layer that seals the battery element by heat-sealing the heat-sealable resin layers together during battery assembly.

[0088] The resin component used in the heat-sealable resin layer 4 is not particularly limited as long as it is heat-sealable, and examples thereof include polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, and carboxylic acid-modified cyclic polyolefin. That is, the resin constituting the heat-sealable resin layer 4 may or may not contain a polyolefin skeleton, but preferably contains a polyolefin skeleton. Whether the resin constituting the heat-sealable resin layer 4 contains a polyolefin skeleton can be determined by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, it is found that the polyolefin skeleton is present at a wave number of 1760 cm. -1 Near and wave number 1780cm -1 A peak derived from maleic anhydride is detected around this point. However, if the degree of acid modification is low, the peak may be small and not be detected. In this case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0089] Specific examples of the polyolefin include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; polypropylenes such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), and random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene); ethylene-butene-propylene terpolymers; etc. Among these polyolefins, polyethylene and polypropylene are preferred.

[0090] The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin constituting the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. Examples of the cyclic monomer constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Styrene is also a constituting monomer. Among these polyolefins, cyclic alkenes are preferred, and norbornene is more preferred.

[0091] The carboxylic acid-modified polyolefin is a polymer obtained by modifying the polyolefin by block polymerization or graft polymerization with a carboxylic acid. Examples of the carboxylic acid used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

[0092] The carboxylic acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a cyclic polyolefin by replacing a portion of the monomers constituting the cyclic polyolefin with an α,β-unsaturated carboxylic acid or its anhydride, or by block or graft polymerizing a cyclic polyolefin with an α,β-unsaturated carboxylic acid or its anhydride. The cyclic polyolefin to be modified with a carboxylic acid is the same as described above. The carboxylic acid used for the modification is the same as that used for the modification of the carboxylic acid-modified polyolefin.

[0093] Among these resin components, preferred are carboxylic acid-modified polyolefins, and more preferred are carboxylic acid-modified polypropylenes.

[0094] The thermally adhesive resin layer 4 may be formed of one type of resin component alone, or may be formed of a blend polymer of two or more types of resin components. Furthermore, the thermally adhesive resin layer 4 may be formed of only one layer, or may be formed of two or more layers of the same or different resin components.

[0095] The thickness of the heat-fusible resin layer 4 can be appropriately selected, but is typically about 8 to 50 μm, and preferably about 10 to 40 μm.

[0096] Furthermore, the heat-sealable resin layer 4 may contain a lubricant, etc., as necessary. When the heat-sealable resin layer 4 contains a lubricant, the formability of the battery packaging material can be improved. The lubricant is not particularly limited, and known lubricants can be used, such as those exemplified for the base material layer 1 above. The lubricant may be used alone, or two or more types may be used in combination. The content of the lubricant in the heat-sealable resin layer 4 is not particularly limited, and from the viewpoint of improving the formability and insulating properties of the electronic packaging material, it is preferably about 0.01 to 0.20 mass %, more preferably about 0.05 to 0.15 mass %.

[0097] [Adhesive layer 5] In the battery packaging material of the present invention, the adhesive layer 5 is a layer that is provided between the barrier layer 3 and the heat-sealable resin layer 4 as needed in order to firmly bond them together.

[0098] The adhesive layer 5 is formed of a resin capable of bonding the barrier layer 3 and the heat-sealable resin layer 4. The resin used to form the adhesive layer 5 can be the same as the adhesive exemplified for the adhesive layer 2 in terms of its adhesion mechanism, type of adhesive component, etc. The resin used to form the adhesive layer 5 can also be a polyolefin-based resin such as polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, or carboxylic acid-modified cyclic polyolefin exemplified for the heat-sealable resin layer 4. From the viewpoint of excellent adhesion between the barrier layer 3 and the heat-sealable resin layer 4, carboxylic acid-modified polyolefin is preferred, and carboxylic acid-modified polypropylene is particularly preferred. That is, the resin constituting the adhesive layer 5 may or may not contain a polyolefin skeleton, but preferably contains a polyolefin skeleton. The presence of a polyolefin skeleton in the resin constituting the adhesive layer 5 can be determined by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when maleic anhydride-modified polyolefin is measured by infrared spectroscopy, a peak at a wavenumber of 1760 cm is observed. -1 Near and wave number 1780cm -1 A peak derived from maleic anhydride is detected around this point. However, if the degree of acid modification is low, the peak may be small and not be detected. In this case, analysis can be performed using nuclear magnetic resonance spectroscopy.

[0099] Furthermore, from the viewpoint of reducing the thickness of the battery packaging material while providing a battery packaging material with excellent formability, it is also preferable that the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Preferred examples of the acid-modified polyolefin include the same carboxylic acid-modified polyolefins and carboxylic acid-modified cyclic polyolefins as exemplified for the heat-sealable resin layer 4.

[0100] The curing agent is not particularly limited as long as it can cure the acid-modified polyolefin, and examples of the curing agent include epoxy-based curing agents, polyfunctional isocyanate-based curing agents, carbodiimide-based curing agents, and oxazoline-based curing agents.

[0101] The epoxy curing agent is not particularly limited as long as it is a compound having at least one epoxy group, and examples of the epoxy curing agent include epoxy resins such as bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, and polyglycerin polyglycidyl ether.

[0102] The polyfunctional isocyanate curing agent is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate curing agent include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymers or nurates thereof, mixtures thereof, and copolymers with other polymers.

[0103] The carbodiimide curing agent is not particularly limited as long as it is a compound having at least one carbodiimide group (-N=C=N-). As the carbodiimide curing agent, a polycarbodiimide compound having at least two carbodiimide groups is preferred.

[0104] The oxazoline-based curing agent is not particularly limited as long as it is a compound having an oxazoline skeleton, and specific examples of the oxazoline-based curing agent include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

[0105] From the viewpoint of improving the adhesion between the barrier layer 3 and the thermally adhesive resin layer 4 by the adhesive layer 5, the curing agent may be composed of two or more types of compounds.

[0106] The content of the curing agent in the resin composition forming the adhesive layer 5 is preferably in the range of approximately 0.1 to 50 mass%, more preferably in the range of approximately 0.1 to 30 mass%, and even more preferably in the range of approximately 0.1 to 10 mass%.

[0107] The thickness of the adhesive layer 5 is not particularly limited as long as it functions as an adhesive layer, but when an adhesive such as that exemplified for the adhesive layer 2 is used, the thickness is preferably about 2 to 10 μm, more preferably about 2 to 5 μm. When a resin such as that exemplified for the heat-fusible resin layer 4 is used, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. When a cured product of an acid-modified polyolefin and a curing agent is used, the thickness is preferably about 30 μm or less, more preferably about 0.1 to 20 μm, and even more preferably about 0.5 to 5 μm. When the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed by applying the resin composition and curing it by heating or the like.

[0108] [Surface coating layer 6] In the battery packaging material of the present invention, a surface coating layer 6 may be provided on the substrate layer 1 (on the side of the substrate layer 1 opposite to the barrier layer 3) as needed for the purpose of improving design, electrolyte resistance, abrasion resistance, formability, etc. The surface coating layer 6 is the layer located on the outermost layer when the battery is assembled.

[0109] The surface coating layer 6 can be formed from a resin composition. Components contained in the resin composition include a resin component, a curing accelerator, and additives (fillers, etc.), as described below.

[0110] The resin component contained in the resin composition preferably contains a thermosetting resin. The thermosetting resin may be any resin that undergoes polymerization when heated to form a polymer network structure and harden. Specific examples of the thermosetting resin include polyvinylidene chloride, polyester resin, epoxy resin, amino resin (melamine resin, benzoguanamine resin, etc.), acrylic resin, urethane resin, phenolic resin, unsaturated polyester resin, and alkyd resin.

[0111] Among these thermosetting resins, from the viewpoints of shortening the curing time and improving moldability and chemical resistance, urethane resins and epoxy resins are preferred, two-component curing urethane resins and two-component curing epoxy resins are more preferred, and two-component curing epoxy resins are particularly preferred.

[0112] Specific examples of two-component curing urethane resins include a combination of a polyol compound (base) and an isocyanate compound (curing agent), and specific examples of two-component curing epoxy resins include a combination of an epoxy resin (base) and an acid anhydride, an amine compound, or an amino resin (curing agent). Furthermore, preferred two-component curing urethane resins include polyfunctional urethane (meth)acrylates, which are combinations of a polyfunctional (meth)acrylate (base) having active hydrogen and a polyisocyanate (curing agent).

[0113] In the two-component curing urethane resin, the polyol compound used as the main component is not particularly limited, and examples thereof include polyester polyol, polyester polyurethane polyol, polyether polyol, polyether polyurethane polyol, etc. These polyol compounds may be used alone or in combination of two or more.

[0114] In addition, the isocyanate compound used as a curing agent in the two-component curing urethane resin is not particularly limited, and examples thereof include polyisocyanate, its adduct, its isocyanurate-modified product, its carbodiimide-modified product, its allophanate-modified product, and its biuret-modified product. Specific examples of polyisocyanate include diphenylmethane diisocyanate (MDI), polyphenylmethane diisocyanate (polymeric MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI), bis(4-isocyanatocyclohexyl)methane (H12MDI), isophorone diisocyanate (IPDI), 1,5-naphthalene diisocyanate (1,5-NDI), 3,3'-dimethyl-4,4'-diphenylene diisocyanate ( Examples of suitable adducts include aromatic diisocyanates such as tetramethyl hexamethylene diisocyanate (TODI) and xylene diisocyanate (XDI); aliphatic diisocyanates such as tramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate and isophorone diisocyanate; alicyclic diisocyanates such as 4,4'-methylenebis(cyclohexyl isocyanate) and isophorone diisocyanate; and polycyclic aromatic diisocyanates such as 1,5-naphthalene diisocyanate (1,5-NDI). Specific examples of adducts include those obtained by adding trimethylolpropane, glycol, or the like to the above polyisocyanates. These isocyanate compounds may be used alone or in combination of two or more.

[0115] These thermosetting resins may also be crosslinkable elastomers. A crosslinkable elastomer is a thermosetting resin that can impart soft segments to a cured product. For example, in the case of a two-component curing urethane resin or a two-component curing epoxy resin among crosslinkable elastomers, the aforementioned base resin may have a structure that can impart soft segments. The crosslinkable elastomer can be used as part of the thermosetting resin used to form the layers that constitute the surface coating layer 6, in order to impart the desired hardness to the layers that constitute the surface coating layer 6.

[0116] These thermosetting resins may be used alone or in combination of two or more. The surface coating layer 6 may be formed of multiple layers. When the surface coating layer 6 is formed of multiple layers, the thermosetting resins used in each layer may be the same or different, and the type of thermosetting resin may be appropriately selected depending on the functions and physical properties that each layer is to have. For example, among the layers constituting the surface coating layer 6, a thermosetting resin having a polycyclic aromatic skeleton and / or a heterocyclic skeleton is preferably used for the layer forming the outermost layer (the outermost layer located opposite the substrate layer 1) from the viewpoint of providing excellent chemical resistance. Specific examples of thermosetting resins having a polycyclic aromatic skeleton include epoxy resins having a polycyclic aromatic skeleton and urethane resins having a polycyclic aromatic skeleton. Specific examples of thermosetting resins having a heterocyclic skeleton include amino resins such as melamine resins and benzoguanamine resins. These thermosetting resins having a polycyclic aromatic skeleton and / or a heterocyclic skeleton may be either one-component curing types or two-component curing types.

[0117] More specific examples of epoxy resins having a polycyclic aromatic skeleton include a reaction product of dihydroxynaphthalene with epihalohydrin; a reaction product of a condensate of naphthol with aldehydes (naphthol novolac resin) with epihalohydrin; a reaction product of a condensate of dihydroxynaphthalene with aldehydes with epihalohydrin; a reaction product of a condensate of mono- or dihydroxynaphthalene with xylylene glycols with epihalohydrin; a reaction product of an adduct of mono- or dihydroxynaphthalene with a diene compound with epihalohydrin; and a reaction product of a polynaphthol in which naphthols are directly coupled with each other with epihalohydrin.

[0118] More specifically, the urethane resin having a polycyclic aromatic skeleton may be a reaction product of a polyol compound and an isocyanate compound having a polycyclic aromatic skeleton.

[0119] (curing accelerator) The resin composition forming the surface coating layer 6 may further contain a curing accelerator in addition to the resin components described above. By using a curing accelerator together with a thermosetting resin, the surface coating layer 6 can be cured in a short time without aging under high temperature conditions during production, and a layer having a specific hardness can be formed.

[0120] Here, the term "curing accelerator" refers to a substance that does not form a crosslinked structure by itself but accelerates the crosslinking reaction of a thermosetting resin, and has the effect of accelerating the crosslinking reaction of a thermosetting resin, and may also form a crosslinked structure by itself.

[0121] The type of curing accelerator is appropriately selected depending on the thermosetting resin used so as to satisfy the above-mentioned hardness, and examples thereof include amidine compounds, carbodiimide compounds, ketimine compounds, hydrazine compounds, sulfonium salts, benzothiazolium salts, and tertiary amine compounds.

[0122] The amidine compound is not particularly limited, but examples thereof include imidazole compounds, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN), and guanidine compounds. Specific examples of the imidazole compound include 2-methylimidazole, 2-ethylimidazole, 2-undecylimidazole, 2,4-dimethylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 1,2-diethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-benzyl-2-methylimidazole, 2,4-diamino-6-[2'-methylimidazole]

[0033] 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1)']-ethyl-S-triazine, 2,4-diamino-6-[2'-undecylimidazolyl]-ethyl-S-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1)']-ethyl-S-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1)']-ethyl-S-triazine isocyanuric oxidation adduct, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 2-aryl-4,5-diphenylimidazole, etc. These amidine compounds may be used alone or in combination of two or more.

[0123] The carbodiimide compound is not particularly limited, and examples thereof include N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, N-[3-(dimethylamino)propyl]-N'-ethylcarbodiimide, N-[3-(dimethylamino)propyl]-N'-ethylcarbodiimide methiodide, N-tert-butyl-N'-ethylcarbodiimide, N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide meso-p-toluenesulfonate, N,N'-di-tert-butylcarbodiimide, N,N'-di-p-tolylcarbodiimide, etc. These carbodiimide compounds may be used alone or in combination of two or more.

[0124] The ketimine compound is not particularly limited as long as it has a ketimine bond (N=C), and examples thereof include ketimine compounds obtained by reacting a ketone with an amine. Specific examples of the ketone include methyl ethyl ketone, methyl isopropyl ketone, methyl tert-butyl ketone, methyl cyclohexyl ketone, diethyl ketone, ethyl propyl ketone, ethyl butyl ketone, dipropyl ketone, dibutyl ketone, and diisobutyl ketone. Specific examples of the amine include aromatic polyamines such as o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, m-xylylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and diaminodiethyldiphenylmethane; and aliphatic polyamines such as ethylenediamine, propylenediamine, butylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexamethylenediamine, trimethylhexamethylenediamine, 1,2-propanediamine, iminobispropylamine, and methyliminobispropylamine. Specific examples include ketimine compounds such as monoamines and polyether-based diamines having an ether bond in the main chain, such as N-aminoethylpiperazine and 3-butoxyisopropylamine; alicyclic polyamines such as isophoronediamine, 1,3-bisaminomethylcyclohexane, 1-cyclohexylamino-3-aminopropane, and 3-aminomethyl-3,3,5-trimethylcyclohexylamine; norbornane-based diamines; polyamidoamines having amino groups at the molecular terminals of polyamides; 2,5-dimethyl-2,5-hexamethylenediamine, menthenediamine, and 1,4-bis(2-amino-2-methylpropyl)piperazine. These ketimine compounds may be used alone or in combination of two or more.

[0125] The hydrazine compound is not particularly limited, but examples thereof include dipic acid dihydrazide, isophthalic acid dihydrazide, etc. These hydrazine compounds may be used alone or in combination of two or more.

[0126] The sulfonium salt is not particularly limited, and examples thereof include alkylsulfonium salts such as 4-acetophenyldimethylsulfonium hexafluoroantimonate, 4-acetophenyldimethylsulfonium hexafluoroarsenate, dimethyl-4-(benzyloxycarbonyloxy)phenylsulfonium hexafluoroantimonate, dimethyl-4-(benzoyloxy)phenylsulfonium hexafluoroarsenate, and dimethyl-4-(benzoyloxy)phenylsulfonium hexafluoroarsenate; benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, 4-acetoxyphenylbenzylmethylsulfonium hexafluoroantimonate, benzyl-4-methoxyphenylmethylsulfonium hexafluoroantimonate, benzyl-3-chloro-4-hydroxyphenylmethylsulfonium hexafluoroarsenate, and 4-methoxybenzyl-4-hydroxyphenylmethylsulfonium hexafluoroarsenate. benzylsulfonium salts such as dibenzyl-4-hydroxyphenylsulfonium hexafluoroantimonate, dibenzyl-4-hydroxyphenylsulfonium hexafluorophosphate, dibenzyl-4-methoxyphenylsulfonium hexafluoroantimonate, and benzyl-4-methoxybenzyl-4-hydroxyphenylsulfonium hexafluorophosphate; and substituted benzylsulfonium salts such as p-chlorobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, p-nitrobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, 3,5-dichlorobenzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, and o-chlorobenzyl-3-chloro-4-hydroxyphenylmethylsulfonium hexafluoroantimonate. These sulfonium salts may be used alone or in combination of two or more.

[0127] The benzothiazolium salt is not particularly limited, and examples thereof include benzylbenzothiazolium salts such as 3-benzylbenzothiazolium hexafluoroantimonate, 3-benzylbenzothiazolium hexafluorophosphate, 3-benzylbenzothiazolium tetrafluoroborate, 3-(p-methoxybenzyl)benzothiazolium hexafluoroantimonate, 3-benzyl-2-methylthiobenzothiazolium hexafluoroantimonate, and 3-benzyl-5-chlorobenzothiazolium hexafluoroantimonate. These benzothiazolium salts may be used alone or in combination of two or more.

[0128] The tertiary amine compound is not particularly limited, but examples thereof include aliphatic tertiary amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, 1,4-diazabicyclo[2.2.2]octane, quinuclidine, and 3-quinuclidinol; aromatic tertiary amines such as dimethylaniline; and heterocyclic tertiary amines such as isoquinoline, pyridine, collidine, and beta-picoline. These tertiary amine compounds may be used alone or in combination of two or more.

[0129] A suitable example of the curing accelerator is one that functions as a thermal acid generator. A thermal acid generator is a substance that generates an acid upon heating and functions as a curing accelerator. Among the curing accelerators described above, specific examples that can function as a thermal acid generator include sulfonium salts and benzothiazolium salts.

[0130] Another suitable example of the curing accelerator is one that has thermal latency, activating under specific heating conditions (e.g., 80 to 200°C, preferably 100 to 160°C) to accelerate the crosslinking reaction of the thermosetting resin. Specific examples of the thermally latent curing accelerators mentioned above include epoxy adducts in which an epoxy compound is added to an amidine compound, a hydrazine compound, a tertiary amine compound, or the like.

[0131] Furthermore, another suitable example of the curing accelerator is one that has hydrolysis potential, which does not function as a curing agent in a sealed state, i.e., in a moisture-proof state, but which hydrolyzes and functions as a curing agent when the sealed state is opened and moisture is present. Specific examples of the hydrolysis potential among the curing accelerators mentioned above include epoxy adducts in which an epoxy compound is added to an amidine compound, a hydrazine compound, a tertiary amine compound, or the like.

[0132] These curing accelerators may be used alone or in combination of two or more. Among these curing accelerators, preferred are amidine compounds and sulfonium salts, and more preferred are amidine compounds.

[0133] These curing accelerators may be used singly or in combination of two or more in the surface coating layer 6. When the surface coating layer 6 is formed of a plurality of layers, the curing accelerators used in the respective layers constituting the surface coating layer 6 may be the same or different, and the type of curing accelerator may be appropriately selected depending on the functions, physical properties, etc. that each layer is to have.

[0134] When a curing accelerator is used, the content of the curing accelerator in the resin composition used to form the surface coating layer 6 is appropriately set depending on the type of thermosetting resin used, the type of curing accelerator, etc., but for example, the total amount of the curing accelerator per 100 parts by mass of the thermosetting resin is about 0.01 to 6 parts by mass, preferably about 0.05 to 5 parts by mass, and more preferably about 0.1 to 2 parts by mass.

[0135] The surface coating layer 6 preferably contains a filler as an additive. That is, the surface coating layer 6 is preferably formed from a resin composition containing the filler. When the surface coating layer 6 contains the filler, an uneven shape can be formed on the surface of the surface coating layer 6, and a matte finish can be imparted to the battery packaging material. Specific examples of the filler include inorganic fillers such as titanium oxide, silica, talc, clay, heavy calcium carbonate, light calcium carbonate, barium sulfate, calcium silicate, synthetic silicate, aluminum hydroxide, and silicate fine powder. Only one type of filler may be used, or two or more types may be mixed and used.

[0136] Among inorganic fillers, inorganic fillers made from silica or precipitated barium sulfate are preferred because they are easy to handle and readily available. Note that precipitated barium sulfate refers to barium sulfate produced using a chemical reaction, and is characterized by the ability to control the particle size.

[0137] The filler content in the surface coating layer 6 is preferably about 2.0 to 8.7% by mass when the filler is silica with an average particle size of about 1.0 to 3.0 μm, and is preferably about 13.0 to 40.0% by mass when the filler is precipitated barium sulfate with an average particle size of less than 1.5 μm. The filler content refers to the content of filler in the surface coating layer 6, and is the content after the solvent has evaporated from the resin composition used to form the surface coating layer 6 containing the filler. The average particle size of the filler is the median size measured with a laser diffraction / scattering particle size distribution analyzer.

[0138] The surface coating layer 6 may contain at least one of a pigment and a dye as an additive. When the surface coating layer 6 contains at least one of a pigment and a dye, whitening during molding can be more effectively suppressed and abrasion resistance can also be improved. Furthermore, when the surface coating layer 6 contains at least one of a pigment and a dye, it is possible to impart distinctiveness to the battery packaging material of the present invention (coloring by at least one of a pigment and a dye), to impart a matte design to the surface of the battery packaging material of the present invention, and to further increase the thermal conductivity of the battery packaging material of the present invention and improve heat dissipation properties.

[0139] The pigment material is not particularly limited and may be either an inorganic pigment or an organic pigment. Specific examples of the inorganic pigment include carbon black, carbon nanotubes, graphite, kaolin, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, cerium oxide, calcium sulfate, lithium carbonate, gold, aluminum, copper, and nickel. Specific examples of the organic pigment include azo pigments, polycyclic pigments, lake pigments, and fluorescent pigments. These pigments may be used alone or in combination of two or more.

[0140] The shape of the pigment is not particularly limited, and examples thereof include spherical, fibrous, plate-like, irregular, and balloon-like shapes. The average particle size of the pigment is also not particularly limited, and is preferably about 0.01 to 3 μm, and more preferably about 0.05 to 1 μm. The average particle size of the pigment is the median size measured with a laser diffraction / scattering particle size distribution analyzer.

[0141] If necessary, the pigment may be subjected to various surface treatments such as an insulating treatment or a high-dispersibility treatment (resin coating treatment).

[0142] The type of dye is not particularly limited as long as it can be dissolved or dispersed in the resin composition used to form the surface coating layer 6, and examples thereof include nitro dyes, azo dyes, stilbene dyes, carbonium dyes, quinoline dyes, methine dyes, thiazole dyes, quinine imine dyes, anthraquinone dyes, indigoid dyes, and phthalocyanine dyes, with azo dyes, carbonium dyes, anthraquinone dyes, and the like being preferred. These dyes may be used alone or in combination of two or more.

[0143] Among these pigments and dyes, from the viewpoint of further improving the heat dissipation properties of the battery packaging material of the present invention, pigments are preferred, inorganic pigments are more preferred, carbon materials such as carbon black, carbon nanotubes, and graphite are even more preferred, and carbon black is particularly preferred.

[0144] When the surface coating layer 6 has a multilayer structure composed of two or more layers, the pigment and / or dye may be contained in any one of these two or more layers, or may be contained in two or more layers. From the viewpoint of reducing the difference in color tone between the molded portion and the unmolded portion after molding of the battery packaging material of the present invention, it is preferable to have the surface coating layer 6 have a multilayer structure composed of two or more layers and to contain the pigment and / or dye in two or more layers, and it is even more preferable to have the surface coating layer 6 have a three-layer structure composed of three layers and to contain the pigment and / or dye in all three layers.

[0145] When a pigment and / or dye is contained in at least one layer constituting the surface coating layer 6, the content thereof may be appropriately set depending on the type of pigment and / or dye used, the distinguishability and heat dissipation properties to be imparted to the battery packaging material of the present invention, etc. For example, the total amount of pigment and / or dye may be about 1 to 30 parts by mass per 100 parts by mass of the resin component contained in the layer containing the pigment and / or dye. From the viewpoint of imparting even better distinguishability, the total amount of pigment and / or dye may be about 3 to 20 parts by mass per 100 parts by mass of the resin component contained in the layer containing the pigment and / or dye. Furthermore, from the viewpoint of imparting even better distinguishability and suppressing a decrease in moldability due to the pigment and / or dye, the total amount of pigment and / or dye may be about 5 to 15 parts by mass per 100 parts by mass of the resin component contained in the layer containing the pigment and / or dye.

[0146] The resin composition used to form the surface coating layer 6 may contain, in addition to the additives described above, other additives such as organic fillers, lubricants, solvents, elastomer resins, etc., as necessary, depending on the functionality that the surface coating layer 6 should have.

[0147] When the surface coating layer 6 contains an organic filler or a lubricant as an additive, a slip effect is imparted to the surface of the battery packaging material of the present invention, thereby improving the formability and processability in press molding and embossing, and improving operability.

[0148] The type of organic filler is not particularly limited, but examples thereof include high-melting-point nylon, acrylate resin, cross-linked acrylic, cross-linked styrene, cross-linked polyethylene, benzoguanamine, etc. The shape of the organic filler is also not particularly limited, but examples thereof include spherical, fibrous, plate-like, amorphous, balloon-like, etc.

[0149] The lubricant is not particularly limited and may be, for example, a non-reactive lubricant or a reactive lubricant. In particular, reactive lubricants have the advantage that they are less likely to bleed out and be lost from the outermost layer constituting the surface coating layer 6, and can suppress the occurrence of powdering and set-off during use and the deterioration of the slip effect over time. Therefore, among lubricants, reactive lubricants are preferred.

[0150] Here, the non-reactive lubricant is, for example, a compound that does not have a functional group that reacts with and chemically bonds to the resin component described above, but can provide slip properties (sliding properties), whereas the reactive lubricant is a compound that has a functional group that reacts with and chemically bonds to the resin component described above, and can provide slip properties (sliding properties).

[0151] Specific examples of non-reactive lubricants include amide-based lubricants, fatty acid amides, metal soaps, hydrophilic silicones, silicone-grafted acrylics, silicone-grafted epoxies, silicone-grafted polyethers, silicone-grafted polyesters, block-type silicone-acrylic copolymers, polyglycerol-modified silicones, and paraffins. Examples of amide-based lubricants that can be used include the amide-based lubricants described above. These non-reactive lubricants may be used alone or in combination of two or more.

[0152] In addition, the type of functional group in the reactive lubricant is appropriately determined depending on the type of resin component used, and examples thereof include a hydroxyl group, a mercapto group, a hydrolyzable silyl group, an isocyanate group, an epoxy group, a polymerizable vinyl group, a (meth)acryloyl group, etc. In the reactive lubricant, the number of functional groups per molecule is not particularly limited, and examples thereof include 1 to 3, and preferably 1 or 2.

[0153] Specific examples of reactive lubricants include modified silicones having the functional groups; modified fluororesins having the functional groups; compounds in which the functional groups have been introduced into fatty acid amides such as stearic acid amide, oleic acid amide, erucic acid amide, and ethylenebisstearic acid amide; metal soaps having the functional groups; and paraffins having the functional groups. These reactive lubricants may be used alone or in combination of two or more. Among these reactive lubricants, preferred are modified silicones having the functional groups, modified fluororesins having the functional groups, and silicone-modified resins having the functional groups. Specific examples of modified silicones include modified silicones obtained by block polymerization of polymers having the functional groups, such as modified silicones obtained by block polymerization of acrylic resins; and modified silicones obtained by graft polymerization of monomers having the functional groups, such as modified silicones obtained by graft polymerization of acrylates. Specific examples of modified fluororesins include modified fluororesins obtained by graft polymerization of a monomer having the functional group, such as a fluororesin obtained by graft polymerization of an acrylate; and fluororesins obtained by block polymerization of a polymer having the functional group, such as a modified fluororesin obtained by block polymerization of an acrylic resin. Specific examples of silicone-modified resins include silicone-modified resins obtained by graft polymerization of a functional group and a silicone, such as a silicone-modified acrylic resin obtained by graft polymerization of an acrylic resin having the functional group. Among these, particularly preferred reactive lubricants include modified silicones in which a monomer or polymer having the functional group is polymerized at one end of the silicone; and modified fluororesins in which a monomer or polymer having the functional group is polymerized at one end of the fluororesin. Examples of such modified silicones and modified fluororesins include commercially available products such as the "Modiper (registered trademark) F / FS series" (manufactured by NOF Corporation) and the "Simac (registered trademark) series" (manufactured by Toagosei Co., Ltd.). These commercially available products can also be used.

[0154] When a lubricant is contained in the resin composition used to form the layer that forms the outermost layer in the surface coating layer 6, the content thereof is not particularly limited, but for example, the total amount of lubricant per 100 parts by mass of the resin component is about 1 to 12 parts by mass, preferably about 3 to 10 parts by mass, and more preferably about 5 to 8 parts by mass.

[0155] Other specific examples of additives include montmorillonite, synthetic mica, hydrotalcite, zeolite, calcium benzoate, calcium oxalate, magnesium stearate, gold, aluminum, copper, and nickel.

[0156] The method for forming the surface coating layer 6 is not particularly limited, and examples thereof include a method of applying a resin composition for forming the surface coating layer 6 onto one surface of the base material layer 1. When an additive is added, the additive may be added to the resin composition, mixed, and then applied.

[0157] The thickness of the surface coating layer 6 is not particularly limited as long as the surface coating layer 6 exhibits the above-mentioned functions, but may be, for example, about 0.5 to 10 μm, and preferably about 1 to 5 μm.

[0158] 3. Manufacturing method for battery packaging material The manufacturing method of the battery packaging material of the present invention is not particularly limited, as long as it can produce a laminate in which layers of a predetermined composition are laminated. An example of the manufacturing method of the battery packaging material of the present invention is as follows. First, a laminate (hereinafter sometimes referred to as "laminate A") is formed in which a base layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order. Specifically, the formation of laminate A can be carried out by a dry lamination method in which an adhesive used to form adhesive layer 2 is applied to base layer 1 or to barrier layer 3, the surface of which has been chemically treated as necessary, by a coating method such as gravure coating or roll coating, and then dried, and then the barrier layer 3 or base layer 1 is laminated and the adhesive layer 2 is cured. At this time, aging may be performed as necessary. When a colored layer 7 is provided between base layer 1 and adhesive layer 2, an ink for forming colored layer 7 is applied to one surface of base layer 1 in advance, and then the adhesive layer 2 and barrier layer 3 are laminated to produce laminate A.

[0159] Next, a heat-fusible resin layer 4 is laminated on the barrier layer 3 of the laminate A. When the heat-fusible resin layer 4 is laminated directly on the barrier layer 3, the resin components constituting the heat-fusible resin layer 4 may be applied onto the barrier layer 3 of the laminate A by a method such as gravure coating or roll coating. In addition, when the adhesive layer 5 is provided between the barrier layer 3 and the heat-sealable resin layer 4, for example, there can be mentioned (1) a method of laminating the adhesive layer 5 and the heat-sealable resin layer 4 on the barrier layer 3 of the laminate A by co-extruding them (co-extrusion lamination method), (2) a method of separately forming a laminate in which the adhesive layer 5 and the heat-sealable resin layer 4 are laminated, and laminating this on the barrier layer 3 of the laminate A by thermal lamination, (3) a method of laminating an adhesive for forming the adhesive layer 5 on the barrier layer 3 of the laminate A by extrusion or solution coating, drying at high temperature, and baking, or the like, and laminating a heat-sealable resin layer 4 previously formed into a sheet-like film on this adhesive layer 5 by thermal lamination, and (4) a method of pouring a molten adhesive layer 5 between the barrier layer 3 of the laminate A and the heat-sealable resin layer 4 previously formed into a sheet-like film, and bonding the laminate A and the heat-sealable resin layer 4 together via the adhesive layer 5 (sandwich lamination method), etc.

[0160] When the surface coating layer 6 is provided, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above-mentioned resin for forming the surface coating layer 6 to the surface of the base material layer 1. The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, after the surface coating layer 6 is formed on the surface of the base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer 6.

[0161] As described above, a laminate is formed which is composed of the optional surface coating layer 6, the substrate layer 1, the optional adhesive layer 2, the optional barrier layer 3 whose surface is chemically treated, the optional adhesive layer 5, and the heat-sealable resin layer 4. In order to strengthen the adhesiveness of the adhesive layer 2 or the adhesive layer 5, the laminate may be further subjected to a heat treatment using a hot roll contact method, hot air, near-infrared light, or far-infrared light. Conditions for such heat treatment include, for example, about 150 to 250°C for about 1 to 5 minutes.

[0162] In the battery packaging material of the present invention, each layer constituting the laminate may be subjected to a surface activation treatment such as corona treatment, blast treatment, oxidation treatment, or ozone treatment, as necessary, in order to improve or stabilize film-forming properties, lamination processing, suitability for secondary processing of final products (pouching, embossing), etc.

[0163] 4. Applications of battery packaging materials The battery packaging material of the present invention is used in a package for hermetically housing battery elements such as a positive electrode, a negative electrode, an electrolyte, etc. That is, a battery can be made by housing a battery element including at least a positive electrode, a negative electrode, and an electrolyte in a package formed from the battery packaging material of the present invention.

[0164] Specifically, a battery element including at least a positive electrode, a negative electrode, and an electrolyte is covered with the battery packaging material of the present invention in such a manner that a flange portion (a region where the heat-sealable resin layers contact each other) is formed around the periphery of the battery element, with the metal terminals connected to the positive electrode and the negative electrode protruding outward, and the heat-sealable resin layers of the flange portion are heat-sealed to form a hermetic seal, thereby providing a battery using the battery packaging material. When a battery element is housed in a package formed from the battery packaging material of the present invention, the package is formed so that the heat-sealable resin portion of the battery packaging material of the present invention faces inside (the surface that contacts the battery element).

[0165] The battery packaging material of the present invention may be used for either primary batteries or secondary batteries, but is preferably used for secondary batteries. The type of secondary battery to which the battery packaging material of the present invention is applied is not particularly limited, and examples include lithium ion batteries, lithium ion polymer batteries, lead acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are preferred applications of the battery packaging material of the present invention. [Example]

[0166] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0167] <Manufacturing of battery packaging materials> Battery packaging materials of Examples 1 to 5 and Comparative Examples 1 to 3 were manufactured according to the following procedure. The layer structure of each battery packaging material is shown in Table 1. In Table 1, SF stands for surface coating layer, ON stands for biaxially oriented nylon film, DL stands for adhesive layer or bond layer formed by dry lamination, AL stands for aluminum foil, PPa stands for maleic anhydride-modified polypropylene, PP stands for random polypropylene, and CPP stands for unstretched polypropylene film. The numerical value added after each layer indicates the thickness of the layer; for example, "ON15" means "a biaxially oriented nylon film with a thickness of 15 μm."

[0168] Example 1 A barrier layer made of aluminum foil (thickness 35 μm, JIS H4160:1994 A8021H-O) chemically treated on both sides was laminated by dry lamination onto a biaxially stretched nylon film (thickness 15 μm) used as a substrate layer. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the barrier layer, forming an adhesive layer (thickness 3 μm) on the barrier layer. Next, the adhesive layer on the barrier layer and the substrate layer were laminated to produce a substrate layer / adhesive layer / barrier layer laminate. The aluminum foil used as the barrier layer was chemically treated using a treatment solution consisting of a phenolic resin, a chromium fluoride compound, and phosphoric acid, with a coating amount of chromium of 10 mg / m. 2 (dry mass) was applied to both sides of an aluminum foil by roll coating, and baked.

[0169] Next, maleic anhydride-modified polypropylene (20 μm thick, placed on the barrier layer side) and random polypropylene (15 μm thick, innermost layer) were co-extruded onto the barrier layer of the obtained laminate, thereby laminating an adhesive layer / thermal-sealable resin layer on the barrier layer. Next, the obtained laminate was heated at 175°C for 2 minutes to obtain a battery packaging material in which the base layer / adhesive layer / barrier layer / adhesive layer / thermal-sealable resin layer were laminated in this order.

[0170] Example 2 A laminate of base material layer / adhesive layer / barrier layer was produced in the same manner as in Example 1. Next, a solution (2 μm thick after curing) containing maleic anhydride-modified polypropylene and a curing agent (epoxy-based) was applied onto the barrier layer of the obtained laminate, and an unstretched polypropylene film (30 μm thick) was further laminated on top of that, thereby obtaining a battery packaging material in which base material layer / adhesive layer / barrier layer / adhesive layer / thermal fusion resin layer were laminated in this order.

[0171] Example 3 A barrier layer made of aluminum foil (35 μm thick, JIS H4160:1994 A8021H-O) chemically treated on both sides was laminated on a biaxially oriented nylon film (15 μm thick) as a substrate layer by dry lamination. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) containing carbon black (median diameter 0.191 μm) was applied to one side of the barrier layer to form an adhesive layer (3 μm thick) on the barrier layer. Next, the adhesive layer on the barrier layer and the substrate layer were laminated, and then aging treatment was performed to produce a substrate layer / adhesive layer (black) / barrier layer laminate. The chemical conversion treatment of the aluminum foil used as the barrier layer was performed in the same manner as in Example 1. The average particle size of the carbon black is the median diameter measured using a laser diffraction / scattering particle size distribution analyzer (Horiba, Ltd., "LA-950").

[0172] Next, a maleic anhydride-modified polypropylene (20 μm thick, placed on the barrier layer side) and a random polypropylene (15 μm thick, innermost layer) were co-extruded onto the barrier layer of the resulting laminate, thereby laminating an adhesive layer / thermal-sealable resin layer on the barrier layer. The resulting laminate was then heated at 175°C for 2 minutes to obtain a laminate consisting of a base layer / adhesive layer / barrier layer / adhesive layer / thermal-sealable resin layer laminated in this order. Next, a resin composition containing precipitated barium sulfate (average particle size: 1 μm) as a filler, erucic acid amide, and an acrylate resin (average particle size: 2 μm) was gravure-coated onto the surface of the base layer of the resulting laminate to a dry thickness of approximately 3 μm to form a surface coating layer. The resulting laminate was then heated to obtain a battery packaging material consisting of a surface coating layer / base layer / adhesive layer (black) / barrier layer / adhesive layer / thermal-sealable resin layer laminated in this order. The average particle size of the precipitated barium sulfate is a median size measured using a laser diffraction / scattering particle size distribution measuring device ("LA-950" manufactured by Horiba, Ltd.).

[0173] Example 4 A black pigment was printed to a thickness of 1 μm on one surface of a biaxially oriented nylon film (thickness 15 μm) serving as a base layer to form a black colored layer. Next, a barrier layer made of aluminum foil (thickness 35 μm, JIS H4160:1994 A8021H-O) that had been chemically treated on both sides was laminated on the colored layer side of the base layer by dry lamination. Specifically, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one surface of the barrier layer to form an adhesive layer (thickness 3 μm) on the barrier layer. Next, the adhesive layer on the barrier layer and the colored layer side of the base layer were laminated, and then aging treatment was performed to produce a laminate of base layer / colored layer (black) / adhesive layer / barrier layer. The chemical conversion treatment of the aluminum foil used as the barrier layer was performed in the same manner as in Example 1.

[0174] Next, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied onto the barrier layer of the obtained laminate, forming an adhesive layer (3 μm thick) on the barrier layer. Furthermore, an unstretched polypropylene film (30 μm thick) was laminated onto the adhesive layer. Next, the obtained laminate was heated and subjected to an aging treatment. Next, a resin composition containing a filler was coated onto the surface of the base layer of the obtained laminate to a thickness of 3 μm, forming a surface coating layer. Next, the obtained laminate was heated and subjected to aging, thereby obtaining a battery packaging material in which the surface coating layer / base layer / colored layer (black) / adhesive layer / barrier layer / adhesive layer / thermally fusion-bondable resin layer were laminated in this order.

[0175] Example 5 A barrier layer made of aluminum foil (thickness 30 μm, JIS H4160:1994 A8021H-O) chemically treated on both sides was laminated on a biaxially oriented nylon film (thickness 15 μm) as a substrate layer by dry lamination. Specifically, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one side of the barrier layer to form an adhesive layer (thickness 3 μm) on the barrier layer. Next, the adhesive layer on the barrier layer and the substrate layer were laminated to produce a substrate layer / adhesive layer / barrier layer laminate. The chemical conversion treatment of the aluminum foil used as the barrier layer was performed in the same manner as in Example 1.

[0176] Next, maleic anhydride-modified polypropylene (thickness 14 μm, placed on the barrier layer side) and random polypropylene (thickness 10 μm, innermost layer) were co-extruded onto the barrier layer of the obtained laminate, thereby laminating an adhesive layer / thermal-sealable resin layer on the barrier layer. Next, the obtained laminate was heated at 175°C for 2 minutes to obtain a battery packaging material in which the base layer / adhesive layer / barrier layer / adhesive layer / thermal-sealable resin layer were laminated in this order.

[0177] The wet tension of the surface on the base layer side of the laminate constituting the battery packaging material obtained in each Example was in the range of 30 to 60 mN / m. The wet tension was measured as follows.

[0178] <Method for measuring wetting tension> The wet tension of the base layer side of the laminate constituting the battery packaging material was measured using a wetting reagent conforming to JIS standards. The test method conformed to JIS K6768:1999. A wet tension test mixture manufactured by Nacalai Tesque was used, and the reagent soaked in a cotton swab was applied to the surface of the base layer side constituting the battery packaging material within a 6 cm radius. 2 A line of about 100 ml of the liquid was applied, and the test was judged based on whether the liquid film broke after 2 seconds. If the liquid film did not break, the test proceeded to the next mixed liquid with the highest surface tension, and if it did break, the test proceeded to the next mixed liquid with the lowest surface tension. This procedure was repeated until a mixed liquid that could wet the surface of the test piece in 2 seconds was selected. The wetting tension measurements were carried out in an environment of 23°C and 50% relative humidity.

[0179] Comparative Example 1 A barrier layer made of aluminum foil (thickness 25 μm, JIS H4160:1994 A8021H-O) chemically treated on both sides was laminated on a polyethylene terephthalate film (thickness 12 μm) as a substrate layer by dry lamination. Specifically, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one side of the barrier layer to form an adhesive layer (thickness 3 μm) on the barrier layer. Next, the adhesive layer on the barrier layer and the substrate layer were laminated to produce a substrate layer / adhesive layer / barrier layer laminate. The chemical conversion treatment of the aluminum foil used as the barrier layer was performed in the same manner as in Example 1.

[0180] Next, maleic anhydride-modified polypropylene (thickness 14 μm, placed on the barrier layer side) and random polypropylene (thickness 10 μm, innermost layer) were co-extruded onto the barrier layer of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was heated at 175°C for 2 minutes to obtain a battery packaging material in which the base layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order.

[0181] Comparative Example 2 A laminate of base material layer / adhesive layer / barrier layer was produced in the same manner as in Comparative Example 1. Next, a solution (2 μm thick after curing) containing maleic anhydride-modified polypropylene and a curing agent (epoxy-based) was applied onto the barrier layer of the obtained laminate, and an unstretched polypropylene film (25 μm thick) was further laminated on top of that, thereby obtaining a battery packaging material in which base material layer / adhesive layer / barrier layer / adhesive layer / thermal fusion resin layer were laminated in this order.

[0182] Comparative Example 3 A laminate of a base material layer / adhesive layer / barrier layer was produced in the same manner as in Example 1. The chemical conversion treatment of the aluminum foil used as the barrier layer was carried out in the same manner as in Example 1. Next, maleic anhydride-modified polypropylene (thickness 20 μm, arranged on the barrier layer side) and random polypropylene (thickness 15 μm, innermost layer) were co-extruded onto the barrier layer of the obtained laminate, thereby laminating an adhesive layer / heat-sealable resin layer on the barrier layer. Next, the obtained laminate was heated at 190°C for 2 minutes to obtain a battery packaging material in which the base material layer / adhesive layer / barrier layer / adhesive layer / heat-sealable resin layer were laminated in this order. [Table 1]

[0183] <Measurement of laminate thickness> The thickness of the laminate constituting each of the battery packaging materials obtained above was measured using a micrometer (Digimatic Micrometer manufactured by Mitutoyo Corporation). The results are shown in Table 2.

[0184] <Fracture energy of laminate> For each battery packaging material obtained above, the breaking energy per meter of unit width in the MD and TD was calculated by obtaining the "measurement load (N / 15 mm)-displacement curve" data measured during tensile testing under the following test conditions for each battery packaging material in the MD and TD. The data was saved in CSV format and integrated using spreadsheet software (Microsoft Excel®) until the laminate broke. The data was then converted to the breaking energy per meter of width for each battery packaging material (divided by 0.015) using the spreadsheet software. The breaking energy per meter of width in the MD and the breaking energy per meter of width in the TD were then summed. Five samples of each battery packaging material were prepared, and the average of the three breaking energy values, excluding the maximum and minimum values, was used as the breaking energy of the laminate. The results are shown in Table 2. (Test conditions) Tensile testing machine: Shimadzu AGS-XPlus Test speed: 50mm / min Specimen width: 15mm Specimen length: 100mm ·Gage distance: 30mm

[0185] For reference, Fig. 6 shows the curve of the measured load (N / 15 mm) vs. displacement obtained in the tensile test (MD) of the battery packaging material of Example 5. The portion obtained by integrating the data of the curve of the measured load (N / 15 mm) vs. displacement is the integral value from the start of the tensile test (displacement 0) to the breaking point P of the laminate, as shown in the schematic diagram of Fig. 7, for example, and corresponds to the area of ​​the shaded portion in Fig. 7.

[0186] <Puncture strength of laminate> The puncture strength of each battery packaging material obtained above was measured from the substrate layer side according to the method specified in JIS Z1707:1995. Specifically, in a measurement environment of 23±2°C and 50±5% relative humidity, a test specimen was fixed using a 115mm diameter table with a 15mm central opening and a pressure plate. A semicircular needle with a 1.0mm diameter and a 0.5mm tip radius was pierced at a rate of 50±5mm per minute, and the maximum stress until the needle penetrated was measured. Five test specimens were measured, and the average value was calculated. The puncture strength was measured using Imada's ZTS-500N force gauge and MX-500N measurement stand. The results are shown in Table 2.

[0187] <Evaluation of formability> Each battery packaging material was cut into a rectangle measuring 90 mm in length (MD) × 150 mm in width (TD) to prepare test samples. These samples were cold-formed (single-stage drawing) into a rectangular mold with an opening of 32 mm (MD) × 54 mm (TD) (female mold, surface roughness in maximum height (nominal Rz value) of 3.2 μm as specified in Table 2 of JIS B 0659-1:2002, Annex 1 (Reference), Reference Surface Roughness Standards for Comparison) and a corresponding mold (male mold, surface roughness in maximum height (nominal Rz value) of 1.6 μm as specified in Table 2 of JIS B 0659-1:2002, Annex 1 (Reference), Reference Surface Roughness Standards for Comparison) at a pressing pressure (surface pressure) of 0.25 MPa, with the forming depth varied in 0.5 mm increments from 0.5 mm, to prepare 20 samples of each. The test sample was placed on a female mold so that the heat-sealable resin layer was positioned on the male mold side. The clearance between the male and female molds was 0.5 mm. After cold molding, the samples were irradiated with a penlight in a dark room to check for pinholes or cracks in the aluminum foil. The deepest molding depth at which no pinholes or cracks occurred in the aluminum foil among the 20 samples was designated A mm, and the number of samples at the shallowest molding depth at which pinholes or other defects occurred in the aluminum foil was designated B. The value calculated using the following formula was used as the limit molding depth for the battery packaging material. Limit forming depth = A mm + (0.5 mm / 20 pieces) x (20 pieces - B pieces)

[0188] [Table 2]

[0189] The battery packaging materials of Examples 1 to 5, in which the thickness of the laminate constituting the battery packaging material was 100 μm or less and the fracture energy of the laminate was 200 J or more in total in one direction perpendicular to the thickness direction of the laminate and in another direction (perpendicular to the one direction and the thickness direction of the laminate), were found to have excellent formability. Furthermore, these battery packaging materials also had high puncture strength measured from the base layer 1 side.

[0190] Example 6 A barrier layer consisting of aluminum foil (JIS H4160:1994 A8021H-O, thickness 35 μm) with an acid-resistant coating formed on both sides was laminated by dry lamination onto a biaxially oriented nylon film (thickness 25 μm) as a base layer. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum foil with an acid-resistant coating formed on both sides, forming an adhesive layer (thickness 3 μm after curing) on ​​the aluminum foil. Next, the adhesive layer on the aluminum foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0191] Next, a maleic anhydride-modified polypropylene (14 μm thick) as an adhesive layer and a polypropylene (10 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer of the resulting laminate, resulting in an adhesive layer / heat-sealable resin layer laminated on the barrier layer. The resulting laminate was then aged and heated to obtain a battery packaging material (total thickness 87 μm) in which a biaxially oriented nylon film (25 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (14 μm) / heat-sealable resin layer (10 μm) were laminated in this order. The layer structure of the battery packaging material is shown in Table 3.

[0192] Erucic acid amide was present as a lubricant on both sides of the obtained battery packaging material to form a lubricant layer.

[0193] Example 7 A barrier layer consisting of aluminum foil (JIS H4160:1994 A8021H-O, thickness 40 μm) with acid-resistant coatings formed on both sides was laminated by dry lamination onto a biaxially oriented nylon film (thickness 25 μm) as a base layer. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum foil with acid-resistant coatings formed on both sides, forming an adhesive layer (thickness 2 μm after curing) on ​​the aluminum foil. Next, the adhesive layer on the aluminum foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0194] Next, a maleic anhydride-modified polypropylene (14 μm thick) as an adhesive layer and a polypropylene (10 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer of the resulting laminate, resulting in an adhesive layer / heat-sealable resin layer laminated on the barrier layer. The resulting laminate was then aged and heated to obtain a battery packaging material (total thickness 91 μm) consisting of a biaxially oriented nylon film (25 μm), adhesive layer (2 μm), barrier layer (40 μm), adhesive layer (14 μm), and heat-sealable resin layer (10 μm) laminated in this order. The layer structure of the battery packaging material is shown in Table 3.

[0195] As in Example 6, erucic acid amide was added as a lubricant to form a lubricant layer on both sides of the obtained battery packaging material.

[0196] Example 8 A barrier layer consisting of aluminum foil (JIS H4160:1994 A8021H-O, thickness 40 μm) with an acid-resistant coating formed on both sides was laminated by dry lamination onto a biaxially oriented nylon film (thickness 15 μm) as a base layer. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum foil with an acid-resistant coating formed on both sides, forming an adhesive layer (thickness 3 μm after curing) on ​​the aluminum foil. Next, the adhesive layer on the aluminum foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0197] Next, a maleic anhydride-modified polypropylene (20 μm thick) as an adhesive layer and a polypropylene (15 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer of the resulting laminate, resulting in an adhesive layer / heat-sealable resin layer laminated on the barrier layer. The resulting laminate was then aged and heated to obtain a battery packaging material (total thickness 93 μm) in which a biaxially oriented nylon film (15 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (20 μm) / heat-sealable resin layer (15 μm) were laminated in this order. The layer structure of the battery packaging material is shown in Table 3.

[0198] As in Example 6, erucic acid amide was added as a lubricant to form a lubricant layer on both sides of the obtained battery packaging material.

[0199] Example 9 A barrier layer consisting of aluminum foil (JIS H4160:1994 A8021H-O, thickness 40 μm) with an acid-resistant coating formed on both sides was laminated by dry lamination onto a biaxially oriented nylon film (thickness 15 μm) as a base layer. Specifically, a two-component curing urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to one side of the aluminum foil with an acid-resistant coating formed on both sides, forming an adhesive layer (thickness 3 μm after curing) on ​​the aluminum foil. Next, the adhesive layer on the aluminum foil and the biaxially oriented nylon film were laminated, and then aging treatment was performed to produce a base layer / adhesive layer / barrier layer laminate.

[0200] Next, a maleic anhydride-modified polypropylene (14 μm thick) as an adhesive layer and a polypropylene (10 μm thick) as a heat-sealable resin layer were co-extruded onto the barrier layer of the resulting laminate, resulting in an adhesive layer / heat-sealable resin layer laminated on the barrier layer. The resulting laminate was then aged and heated to obtain a battery packaging material (total thickness 82 μm) in which a biaxially oriented nylon film (15 μm) / adhesive layer (3 μm) / barrier layer (40 μm) / adhesive layer (14 μm) / heat-sealable resin layer (10 μm) were laminated in this order. The layer structure of the battery packaging material is shown in Table 3.

[0201] As in Example 6, erucic acid amide was added as a lubricant to form a lubricant layer on both sides of the obtained battery packaging material.

[0202] [Table 3]

[0203] In Table 3, the numerical values ​​in the laminate structure indicate thickness (μm). Furthermore, ONy indicates a biaxially oriented nylon film, DL indicates an adhesive layer or a bonding layer formed by a dry lamination method, ALM indicates an aluminum foil, PPa indicates an adhesive layer formed from maleic anhydride-modified polypropylene, PP indicates a heat-sealable resin layer formed from polypropylene, and CPP indicates a heat-sealable resin layer formed from non-oriented polypropylene (CPP).

[0204] <Measurement of laminate thickness> The thickness of the laminate constituting each of the battery packaging materials obtained in Examples 6 to 9 was measured in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 3. The results are shown in Table 4.

[0205] <Puncture strength of laminate> The puncture strength of each of the battery packaging materials obtained in Examples 6 to 9 was measured from the base layer side by a method conforming to the provisions of JIS Z1707:1995 in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 3. The results are shown in Table 4.

[0206] <Fracture energy of laminate> The breaking energy of the laminate was measured for each of the battery packaging materials obtained in Examples 6 to 9 in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 3. The results are shown in Table 4.

[0207] <Evaluation of curl due to molding> Each battery packaging material obtained in Examples 6 to 9 was cut into a strip measuring 150 mm in the transverse direction (TD) × 90 mm in the machine direction (MD), which was used as a test sample. A 31.6 mm × 54.5 mm rectangular male mold (the surface had a maximum height roughness (nominal Rz value) of 1.6 μm, a corner R of 2.0 mm, and a ridge R of 1.0 mm, as specified in Table 2 of the comparative surface roughness standard specimen in Appendix 1 of JIS B 0659-1:2002 (reference)) was placed between the male mold and a female mold (the surface had a maximum height roughness (nominal Rz value) of 1.6 μm, a corner R of 2.0 mm, and a ridge R of 1.0 mm, as specified in Table 2 of the comparative surface roughness standard specimen in Appendix 1 of JIS B 0659-1:2002 (reference)) with a clearance of 0.3 mm. The maximum height roughness (nominal Rz value) of the comparative surface roughness standard specimen, as specified in Table 2, was 3.2 μm. Using a mold with a corner radius of 2.0 mm and a ridge radius of 1.0 mm, the test sample was placed on a female mold with the heat-sealable resin layer facing the male mold. The test sample was then cold-formed (single-stage, drawn-in molding) at a pressure (surface pressure) of 0.25 MPa to obtain a dimension of 31.6 mm (MD) × 54.5 mm (TD) and a molding depth of 6 mm. Details of the molding position are shown in FIG. 8. As shown in FIG. 8, molding was performed at a position where the shortest distance d between the rectangular molding portion M and the end P of the battery packaging material 10 was 70.5 mm. The molding portion M indicates the position where a recess was formed by the mold. Next, the molded battery packaging material 10 was placed on a horizontal surface 20 as shown in FIG. 9. The maximum value t of the vertical distance y from the horizontal surface 20 to the end P was determined as the maximum height of the curled portion. The curl due to molding is smaller the value, indicating a better battery packaging material. The results are shown in Table 4.

[0208] <Evaluation of formability> The battery packaging materials obtained in Examples 6 to 9 were evaluated for moldability in the same manner as in Examples 1 to 5 and Comparative Examples 1 to 3. The results are shown in Table 4.

[0209] <Molding depth at which the barrier layer thickness becomes 20 μm> Each battery packaging material obtained in Examples 6 to 9 was cut into a strip of 90 mm length (MD) × 150 mm width (TD) to serve as a test sample. A rectangular male mold of 31.6 mm length (MD) × 54.5 mm width (TD) (the surface had a maximum height roughness (nominal value of Rz) of 1.6 μm, a corner R of 2.0 mm, and a ridge R of 1.0 mm, as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Appendix 1 (Reference)) was placed in contact with a female mold with a clearance of 0.3 mm between the male mold and the female mold (the surface had a maximum height roughness (nominal value of Rz) of 1.6 μm, a corner R of 2.0 mm, and a ridge R of 1.0 mm, as specified in Table 2 of the comparative surface roughness standard specimen in JIS B 0659-1:2002, Appendix 1 (Reference)). The maximum height roughness (nominal Rz value) of the comparative surface roughness standard piece is 3.2 μm as specified in Table 2. Using a straight mold with a corner R of 2.0 mm and a ridge R of 1.0 mm, the test sample was placed on the female mold with the heat-fusible resin layer side of the test sample positioned on the male mold side, and the test sample was pressed with a pressure (surface pressure) of 0.25 MPa to perform cold forming (single-stage drawing forming).

[0210] Using this cold forming method, forming was performed sequentially under conditions in which the forming depth was increased in increments of 0.5 mm starting from 2.0 mm, and the relationship between the thickness a of the corner P of the barrier layer of the formed test sample (see Figure 9) and the forming depth was plotted and an approximate straight line was drawn to create a graph. From this graph, the forming depth at which the thickness a of the corner P of the barrier layer became 20 μm was determined.

[0211] The thickness a of the barrier layer of the molded test sample was measured by cutting the battery packaging material in two by using a microtome (REM-710 lithratome, manufactured by Yamato Koki Kogyo Co., Ltd.) in the thickness direction along a line connecting the opposing corners P of the roughly rectangular protruding portion when the test sample was viewed from the base layer side, and observing the cross section of the corner P of one of the divided test samples with a laser microscope (VK-9700, manufactured by Keyence Corporation). One of the divided test samples had two corners, and the thickness a of the barrier layer was taken as the average value of the thicknesses a of the barrier layer at these corners. A schematic diagram of the barrier layer of the molded test sample is shown in Figure 10. The position of the thickness of the corner P is the point where the radius of curvature of the corner P (curved portion) formed by molding is smallest, and usually refers to the center portion from the start to the end of the curvature.

[0212] [Table 4] [Explanation of symbols]

[0213] 1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Heat-fusible resin layer 5 Adhesive layer 6 Surface coating layer 7 Colored layer

Claims

1. The laminate is composed of at least a base layer, a barrier layer, and a heat-sealable resin layer in this order, The thickness of the laminate is 91 μm or less, The laminate is subjected to a tensile test under the following test conditions, and the breaking energy per unit width of 1 m is calculated from a curve of a measured load (N / 15 mm) versus a displacement, where the breaking energy is calculated from the curve of a measured load (N / 15 mm) versus a displacement, and the sum X+Y of the breaking energy X in one direction perpendicular to the thickness direction of the laminate and the breaking energy Y in another direction perpendicular to both the one direction and the thickness direction of the laminate is 200 J or more. (Test conditions) Test speed: 50 mm / min Test piece width: 15 mm Gauge distance: 30mm

2. The battery packaging material according to claim 1 , wherein the one direction is the MD of the laminate and the other direction is the TD of the laminate.

3. 3. The battery packaging material according to claim 1, wherein the laminate has a puncture strength of 15 N or more measured from the base material layer side by a method conforming to the provisions of JIS Z1707:1995.

4. The battery packaging material according to any one of claims 1 to 3, further comprising an adhesive layer between the substrate layer and the barrier layer.

5. The battery packaging material according to claim 4 , wherein the adhesive layer contains a colorant.

6. The battery packaging material according to claim 4 or 5, further comprising a colored layer between the base material layer and the adhesive layer.

7. The battery packaging material according to any one of claims 1 to 6, further comprising a surface coating layer on the opposite side of the substrate layer from the barrier layer.

8. The battery packaging material according to claim 7 , wherein a lubricant is present on at least one of the surface and the interior of the surface coating layer.

9. The battery packaging material according to claim 7 , wherein two or more types of lubricants are present on at least one of the surface and the interior of the surface coating layer.

10. 8. The battery packaging material according to claim 7, wherein at least two selected from the group consisting of amide-based lubricants, fatty acid amides, metal soaps, hydrophilic silicones, silicone-grafted acrylics, silicone-grafted epoxies, silicone-grafted polyethers, silicone-grafted polyesters, block-type silicone-acrylic copolymers, polyglycerol-modified silicones, paraffins, and reactive lubricants are present on at least one of the surface and the interior of the surface coating layer.

11. The battery packaging material according to any one of claims 7 to 10, wherein the surface coating layer contains titanium oxide.

12. The battery packaging material according to any one of claims 7 to 11, wherein the surface coating layer contains silica.

13. The battery packaging material according to any one of claims 7 to 12, wherein the surface coating layer contains kaolin.

14. The battery packaging material according to any one of claims 1 to 13, wherein the barrier layer comprises at least one of an aluminum foil and a stainless steel foil.

15. The battery packaging material according to any one of claims 1 to 14, wherein two or more types of lubricants are present on at least one of the surface and the interior of the base material layer.

16. The battery packaging material according to any one of claims 1 to 14, wherein at least two selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides are present on at least one of the surface and the interior of the base material layer.

17. The battery packaging material according to any one of claims 1 to 16, wherein two or more types of lubricants are present on at least one of the surface and the interior of the heat-sealable resin layer.

18. The battery packaging material according to any one of claims 1 to 16, wherein at least two selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides are present on at least one of the surface and the interior of the heat-sealable resin layer.

19. A battery, comprising a battery element including at least a positive electrode, a negative electrode, and an electrolyte, housed in a package formed from the battery packaging material according to any one of claims 1 to 18.

20. The method includes a step of laminating at least a base layer, a barrier layer, and a thermally adhesive resin layer in this order to obtain a laminate, The thickness of the laminate is 91 μm or less, The laminate is subjected to a tensile test under the following test conditions, and the breaking energy per unit width of 1 m is calculated from a curve of a measured load (N / 15 mm) versus a displacement amount, and the breaking energy per unit width of 1 m is calculated from the curve of a measured load (N / 15 mm) versus a displacement amount, and the sum X+Y of the breaking energy X in one direction perpendicular to the thickness direction of the laminate and the breaking energy Y in another direction perpendicular to both the one direction and the thickness direction of the laminate is 200 J or more. (Test conditions) Test speed: 50 mm / min Test piece width: 15 mm Gauge distance: 30mm

21. an adhesive layer is laminated between the barrier layer and the heat-sealable resin layer; The adhesive layer and the heat-sealable resin layer are (1) a method of laminating the adhesive layer and the heat-sealable resin layer by co-extruding them; (2) a method of forming a laminate in which the adhesive layer and the heat-sealable resin layer are laminated, and laminating the laminate on the barrier layer by a thermal lamination method; (3) A method in which an adhesive for forming the adhesive layer is applied to the barrier layer by extrusion or solution coating, and the heat-fusible resin layer, which has been formed into a sheet shape in advance, is laminated on the adhesive layer by thermal lamination, or (4) A method in which the molten adhesive layer is poured between the barrier layer and the heat-fusible resin layer, which has been formed into a sheet shape in advance, and the heat-fusible resin layer is bonded to the barrier layer via the adhesive layer. The method for producing the battery packaging material according to claim 20, wherein the battery packaging material is formed by the following steps.

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