Quality management method in molding step of exterior material for power storage device, manufacturing method of power storage device, exterior material for power storage device, and power storage device

Abstract

To provide a novel quality management method in a molding step of an exterior material for power storage device.SOLUTION: The present invention relates to a quality management method in a molding step of an exterior material for power storage device. In the quality management method, an exterior material for power storage device constituted of a laminate comprising at least a substrate layer, a barrier layer and a heat fusible resin layer successively from the outside is molded so as to protrude from the side of the heat fusible resin layer to the side of the substrate layer. The exterior material for power storage device with which a recess for accommodating a power storage device element therein is formed at the side of the heat fusible resin layer is subjected to quality management. The quality management method in the molding step of the exterior material for power storage device includes a determination step of extracting the test target exterior material for power storage device from among the exterior materials for power storage device with the recesses formed therein, measuring an L* value in an L*a*b*color space of reflection light according to an SCI system and on a measurement condition of a field of view 10° and a light source F2 regarding a curved surface part and a non-curved surface part of an outer surface forming the recess of the test target exterior material for power storage device, and determining whether or not the exterior material for power storage device with the recess formed therein is a non-defective on the basis of a magnitude of a difference of the L* values.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a quality control method in a molding process of an exterior material for a power storage device, a method for manufacturing a power storage device, an exterior material for a power storage device, and a power storage device.

Background Art

[0002] Conventionally, various types of power storage devices have been developed. In all power storage devices, an exterior material is an essential member for sealing power storage device elements such as electrodes and electrolytes. Conventionally, a metal exterior material has been frequently used as the exterior material for a power storage device.

[0003] On the other hand, in recent years, with the improvement in performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., various shapes have been required for power storage devices, and thinning and weight reduction have been demanded. However, the conventionally frequently used metal exterior material for a power storage device has drawbacks that it is difficult to follow the diversification of shapes and there is also a limit to weight reduction.

[0004] Therefore, in recent years, as an exterior material for a power storage device that can be easily processed into various shapes and can achieve thinning and weight reduction, a film-like laminate in which a base material layer / a barrier layer / a heat-sealable resin layer are sequentially laminated has been proposed (see, for example, Patent Document 1).

[0005] In such an exterior material for a power storage device, generally, a concave portion is formed by cold forming, power storage device elements such as electrodes and electrolytic solution are arranged in the space formed by the concave portion, and by heat-sealing the heat-sealable resin layer, a power storage device in which the power storage device elements are housed inside the exterior material for a power storage device can be obtained.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In an exterior material for a power storage device formed by the film-like laminate as described above, a bent portion is formed in the exterior material for a power storage device by forming a recess for housing the power storage device element. In this bent portion, since the exterior material for a power storage device is stretched, whitening may occur on the surface portion. Whitening due to the molding of the exterior material for a power storage device leads to poor appearance of the power storage device, and thus is subject to quality control in the molding of the exterior material for a power storage device. In this quality control, for example, when the exterior material for a power storage device is colored or when the degree of whitening is large, the presence or absence of whitening can be visually confirmed.

[0008] However, as a result of investigations by the present inventors, in the bent portion where the recess of the exterior material for a power storage device is formed, although whitening is difficult to be visually confirmed, when observing the bent portion (the curved surface portion of the outer surface of the exterior material for a power storage device) with a scanning electron microscope or the like, it has been found that very fine cracks may be formed. Therefore, it has become clear that a new quality control method is required in the molding process of the exterior material for a power storage device.

[0009] Under such circumstances, the main object of the present disclosure is to provide a new quality control method in the molding process of the exterior material for a power storage device.

Means for Solving the Problems

[0010] The inventors of the present disclosure have conducted intensive studies to solve the above problems. As a result, in the molding process of the exterior material for a power storage device, a test target exterior material for a power storage device is extracted from the exterior materials for a power storage device in which recesses are formed, and for the curved surface portion and the non-curved surface portion of the outer surface forming the recess of the test target exterior material for a power storage device, respectively, under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L * a * b * in the color space* Measure the value to obtain L * Based on the magnitude of the difference in values (i.e., L * the absolute value of the difference in values), it is found that by determining whether the exterior material for a power storage device with a recess formed is a non-defective product, quality control can be performed with high precision as compared to the conventional visual inspection method.

[0011] Based on these findings, the present disclosure has been completed through further consideration. That is, the present disclosure provides an invention in the following aspects. A quality control method in a molding process of an exterior material for a power storage device, The quality control method includes, at least, an exterior material for a power storage device composed of a laminate including a base material layer, a barrier layer, and a heat-sealable resin layer in order from the outside, which is molded so as to protrude from the heat-sealable resin layer side toward the base material layer side, and the exterior material for a power storage device in which a recess for accommodating a power storage device element is formed on the heat-sealable resin layer side is the object of quality control. From the exterior materials for power storage devices with recesses formed, an exterior material for a test target power storage device is extracted, and for the curved surface portion and non-curved surface portion of the outer surface forming the recess of the exterior material for the test target power storage device, respectively, under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L * a * b * L in the color space * Measure the value to obtain L * Based on the magnitude of the difference in values, the quality control method includes a determination step of determining whether the exterior material for a power storage device with a recess formed is a non-defective product. A quality control method in a molding process of an exterior material for a power storage device.

Advantages of the Invention

[0012] According to the present disclosure, a novel quality control method in the molding process of an exterior material for a power storage device can be provided. Further, according to the present disclosure, a manufacturing method of an exterior material for a power storage device using the quality control method can also be provided. Further, according to the present disclosure, an exterior material for a power storage device determined to be a good product by the quality control method, and further, a power storage device using the exterior material for a power storage device can be provided.

Brief Description of the Drawings

[0013]

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[0014] The quality control disclosed herein is a quality control method in a molding process of an electrical storage device exterior material, and the quality control method targets electrical storage device exterior materials in which the electrical storage device exterior material is made of a laminate including at least, in order from the outside, a base material layer, a barrier layer, and a heat-sealable resin layer, and is molded so as to protrude from the heat-sealable resin layer side to the base material layer side, and a recess for accommodating an electrical storage device element is formed on the heat-sealable resin layer side. The quality control method selects electrical storage device exterior materials to be tested from the electrical storage device exterior materials in which a recess is formed, and measures the L of reflected light for the curved and non-curved portions of the outer surface that form the recess of the electrical storage device exterior material to be tested under measurement conditions of an SCI method, a field of view of 10°, and a light source F2. * a * b * L in color space * Measure the value and * The method is characterized in that it includes a determination step of determining whether or not the packaging material for an electricity storage device in which the recesses are formed is a non-defective product based on the magnitude of the difference in the L * Based on the magnitude of the difference in the values, it can be determined whether or not the packaging material for an electricity storage device in which the recesses are formed is a non-defective product.

[0015] The quality control method in the molding process of an exterior material for an electricity storage device, the manufacturing method of an electricity storage device, the exterior material for an electricity storage device, and the electricity storage device according to the present disclosure will be described in detail below. 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 more and 15 mm or less.

[0016] 1. Quality control method The quality control method of the present disclosure is a quality control method in the molding process of the exterior material for a power storage device. In the quality control method of the present disclosure, the exterior material for a power storage device to be the object of quality control is composed of a laminate including, at least from the outside in order, a base material layer, a barrier layer, and a heat-sealable resin layer. Details of the laminate configuration of the exterior material for a power storage device and each layer will be described later.

[0017] Further, in the quality control method of the present disclosure, the exterior material for a power storage device to be the object of quality control is molded so as to protrude from the heat-sealable resin layer side toward the base material layer side, and a recess for accommodating a power storage device element is formed on the heat-sealable resin layer side. That is, the exterior material for a power storage device has a recess formed by molding. As will be described later, the molding can be performed using a mold or the like.

[0018] The shape of the recess formed in the exterior material for a power storage device is not particularly limited as long as a space for accommodating the power storage device element is formed. Specific examples of the shape of the recess include a substantially rectangular shape in plan view and a substantially circular shape in plan view when observed from the base material layer 1 side. FIGS. 5 and 6 show schematic views in which a recess 100 having a rectangular shape in plan view is provided in the exterior material 10 for a power storage device. Note that the substantially rectangular shape in plan view includes not only the case where the corners of the rectangle are right angles but also a rounded shape as shown in FIGS. 5 and 6. For example, in the recess having a rectangular shape in plan view shown in the schematic views of FIGS. 5 and 6, the curved surface portion 11 includes a corner portion 11a and a ridge line portion 11b protruding toward the base material layer 1 side, and the surface of the corner portion 11a and the ridge line portion 11b on the base material layer 1 side has a predetermined radius of curvature R. The recess 100 having a rectangular shape in plan view forms a rectangular parallelepiped-shaped space, and the power storage device element is accommodated in the space. If the shape of the recess is a circular shape in plan view, the recess forms a cylindrical space, and the power storage device element is accommodated in the space.

[0019] Further, the size of the recess 100 is not particularly limited and is appropriately designed according to the size of the power storage device (i.e., the size of the power storage device element to be accommodated) and the like. For example, when the shape of the recess is rectangular in plan view, when the exterior material 10 for the power storage device is observed from the base material layer 1 side, the length of the long side of the recess 100 is, for example, about 20 mm or more, preferably about 30 mm or more, more preferably about 50 mm or more. Also, the length of the long side of the recess 100 is, for example, about 600 mm or less, preferably about 400 mm or less, more preferably about 200 mm or less. Preferred ranges for the length of the long side of the recess 100 include about 20 to 600 μm, about 20 to 400 μm, about 20 to 200 μm, about 30 to 600 μm, about 30 to 400 μm, about 30 to 200 μm, about 50 to 600 μm, about 50 to 400 μm, about 50 to 200 mm. Also, when the exterior material 10 for the power storage device is observed from the base material layer 1 side, the length of the short side of the recess 100 is, for example, about 10 mm or more, preferably about 20 mm or more, more preferably about 30 mm or more. Also, the length of the short side of the recess 100 is, for example, about 300 mm or less, preferably about 200 mm or less, more preferably about 100 mm or less. Preferred ranges for the length of the short side of the recess 100 include about 10 to 300 μm, about 10 to 200 μm, about 10 to 100 μm, about 20 to 300 μm, about 20 to 200 μm, about 20 to 100 μm, about 30 to 300 μm, about 30 to 200 μm, about 30 to 100 mm. The length of the long side of the recess 100 and the length of the short side may be the same (i.e., the shape of the recess 100 is square in plan view).

[0020] Further, the depth D (see FIG. 6) of the recess 100 is not particularly limited and is appropriately designed according to the size of the power storage device (i.e., the size of the power storage device element to be accommodated) and the like. For example, in the case of the exterior material 10 for the power storage device having the total thickness described later, about 4 to 10 mm can be mentioned.

[0021] The recess 100 provided in the electricity storage device packaging material 10 is formed by molding the film-like electricity storage device packaging material. Specifically, using a mold (female mold) arranged on the base material layer 1 side of the laminate constituting the electricity storage device packaging material and a mold (male mold) arranged on the heat-sealable resin layer 4 side, the laminate is molded (generally cold-molded) so that it protrudes from the heat-sealable resin layer 4 side to the base material layer 1 side, thereby forming the recess 100 on the heat-sealable resin layer 4 side in which the electricity storage device element is housed.

[0022] The quality control method of the present disclosure is characterized by including a determination step of determining whether or not an electrical storage device packaging material having a recess formed therein is a non-defective product. In the determination step, a test electrical storage device packaging material is extracted from electrical storage device packaging materials 10 having a recess 100 formed therein, and the curved surface portion 11 and the non-curved surface portion 12 of the outer surface forming the recess of the test electrical storage device packaging material are measured using the SCI method, a field of view of 10°, and a light source F2, and the L of reflected light is measured. * a * b * L in color space * Measure the value and * Whether or not the electrical storage device packaging material having a recess formed therein is a non-defective product is determined based on the magnitude of the difference in values. When the quality control method of the present disclosure is used as part of the manufacturing process of an electrical storage device, the electrical storage device packaging materials to be tested may be selected at random or at a predetermined rate (for example, one in every 1,000 to 10,000 electrical storage device packaging materials having a recess formed therein may be selected as the electrical storage device packaging material to be tested), or all electrical storage device packaging materials having a recess formed therein may be selected as the electrical storage device packaging material to be tested. When all electrical storage device packaging materials having a recess formed therein are selected as the electrical storage device packaging material to be tested, the L * It is desirable to automate the measurement of values and incorporate them into the production line.

[0023] As described above, by forming the recess for accommodating the power storage device element, a bent portion (see the curved surface portions 11 and 13 in FIG. 6) is formed in the exterior material for the power storage device. In this bent portion, since the exterior material for the power storage device is stretched by molding, whitening may occur on the surface portion. Whitening due to molding of the exterior material for the power storage device leads to poor appearance of the power storage device, and thus it is a subject of quality control in the molding of the exterior material for the power storage device. In this quality control, for example, when the exterior material for the power storage device is colored or when the degree of whitening is large, the presence or absence of whitening can be visually confirmed. However, as a result of investigations by the present inventors, in the bent portion that forms the recess of the exterior material for the power storage device, although whitening is not visually confirmed, when observing the bent portion (the curved surface portion on the outer surface of the exterior material for the power storage device) with a scanning electron microscope or the like, very fine cracks may be formed. Therefore, it is desired to further improve the accuracy of the quality control method in the molding process of the exterior material for the power storage device.

[0024] In the quality control method of the present disclosure, regarding the curved surface portion of the recess formed by molding, L * the magnitude of the difference in values (that is, the absolute value of the difference in L * values) enables suitable detection of the quality such as whether very fine cracks are formed in the curved surface portion. Therefore, if the quality control method of the present disclosure is used in the manufacture of the power storage device, in accordance with the quality required for the power storage device, the evaluation criteria for the magnitude of the difference in L * values can be appropriately set, and it is possible to suitably suppress the production of defective products in the molding process of the exterior material for the power storage device.

[0025] L * Regarding the evaluation criteria for the difference in values, it can be appropriately set according to the quality required for the power storage device. For example, from the viewpoint of controlling whitening in the curved surface portion 11, the L * value of the curved surface portion 11 and the L *The absolute value of the difference therefrom (the absolute value of the difference determined to be a good product) is preferably 2.0 or less, more preferably 1.8 or less, still more preferably 1.5 or less, still more preferably 1.0 or less, still more preferably 0.5 or less, and particularly preferably 0.3 or less. Also, from this viewpoint, the L of the curved surface portion 11 * value and the L of the non-curved surface portion 12 * Preferred ranges of the absolute value of the difference between the values include about 0.0 to 2.0, about 0.0 to 1.8, about 0.0 to 1.5, about 0.0 to 1.0, about 0.0 to 0.5, and about 0.0 to 0.3.

[0026] In the molding for forming a concave portion in the exterior material for a power storage device, the largest strain is applied to the bent portion, and minute cracks are likely to occur. For example, when a crack occurs in a layer constituting the exterior material for a power storage device such as a surface coating layer, a gap is generated, the luster of the base is exposed, and the L of the curved surface portion becomes higher than that of the non-curved surface portion. * value. For example, even in an exterior material for a power storage device having excellent electrolyte resistance, if minute cracks are generated in the curved surface portion formed by molding, the electrolyte penetrates from the minute cracks, leading to peeling of the exterior material. L * As a design of an exterior material for a power storage device in which the difference in the L value is small, in a hard exterior material for a power storage device, it cannot follow the molding and cracks are generated, so it can be adjusted by making it flexible even if it is hard. Also, even if the exterior material for a power storage device is hard and flexible, if there are many additives such as wax and particles, the adhesion at the boundary between the resin and the particles or between the resin and the wax is weak, and cracks are likely to occur from the boundary. Therefore, it is preferable to adjust the content of the additives to the minimum necessary.

[0027] In addition, in a power storage device, for example, if fine cracks are formed in the curved surface portion 11 of the exterior material 10 for the power storage device, depending on the degree of the cracks, when the electrolytic solution adheres to the surface of the exterior material for the power storage device in the manufacturing process of the power storage device, the electrolytic solution may penetrate into the cracks, and the layers constituting the exterior material for the power storage device may peel off. From the viewpoint of performing quality control so as to manufacture a power storage device excellent in electrolytic solution resistance, in the determination process, the L * value of the curved surface portion 11 and the L * value of the non-curved surface portion 12, the absolute value of the difference therebetween (the absolute value of the difference determined to be a good product) is preferably controlled under conditions stricter than the above whitening, preferably 1.5 or less, more preferably 1.0 or less, still more preferably 0.5 or less, and particularly preferably 0.3 or less. Note that the absolute value of the difference between the L * value of the curved surface portion 11 and the L * value of the non-curved surface portion 12 is 0.0 or more. The preferable range of the absolute value of the difference between the L * value of the curved surface portion 11 and the L * value of the non-curved surface portion 12 includes about 0.0 to 1.5, about 0.0 to 1.0, about 0.0 to 0.5, and about 0.0 to 0.3. Further, from the same viewpoint, the preferable range of the absolute value of the difference between the a * value of the curved surface portion 11 and the a * value of the non-curved surface portion 12 (that is, the absolute value and the absolute value of the difference determined to be a good product) includes about 0.00 to 0.12. From the same viewpoint, the preferable range of the absolute value of the difference between the b * value of the curved surface portion and the b * value of the non-curved surface portion (that is, the absolute value and the absolute value of the difference determined to be a good product) includes about 0.00 to 0.60. Further, from the same viewpoint, the value of ΔE * ab is preferably about 1.8 or less, more preferably about 1.0 or less. Also, the preferable range of the value of ΔE * ab includes about 0.0 to 1.8 and about 0.0 to 1.0. Note that the value of ΔE * ab, ΔE * ab = [(ΔL) 2 +(Δa) 2 +(Δb) 2 1 / 2 ​It can be calculated based on the formula.

[0028] In the present disclosure, the determination step can be specifically carried out as follows. For each of the curved surface portion 11 on the outer surface on the base material layer 1 side forming the concave portion 100 of the exterior material for the power storage device, which is the curved surface portion 11 protruding toward the base material layer 1 side of the exterior material 10 for the power storage device, and the non-curved surface portion 12 (the non-curved surface portion 12 shown in the schematic diagrams of FIGS. 5 and 6) on the outer surface on the base material layer 1 side forming the concave portion 10, L * a * b * L in the color space * value is measured using a spectrocolorimeter (for example, a spectrocolorimeter (CM-700d) manufactured by Konica Minolta) calibrated with a white calibration cap (for example, CM-A177: manufactured by Konica Minolta). The observation condition is set to 10°, the observation light source is F2, and the SCI mode is set (JIS Z8722-2009). Next, for the curved surface portion 11 and the non-curved surface portion 12 to be measured, the L of the outer surface (the surface on the base material layer 1 side) * value is measured at normal temperature and normal humidity. For the curved surface portion 11, the measurement diameter is set to 8 mmφ, and for the non-curved surface portion 12, the measurement diameter is set to 3 mmφ for measurement. In addition, the a * value and the b * value can also be measured under these measurement conditions together with the measurement of the L * value.

[0029] L * The curved surface portion 11 to be measured for the L value is the most stretched portion (that is, the portion where fine cracks are most likely to occur) among the curved surface portions 11 forming the concave portion 100 by molding (molding in the formation of the concave portion 100). The most stretched portion is the portion where the difference in the L * value is the largest, and is also the portion where the L * value of the curved surface portion 11 is the largest. For example, for a rectangular concave portion 100 in plan view as shown in the schematic diagrams of FIGS. 5 and 6, among the curved surface portions 11 (rectangular in plan view), the corner portion 11a is the most stretched portion, so the corner portion 11a is used as the L *It is preferable to be the object of value measurement. Although there are four corner portions 11a corresponding to the shape of the molding die, if the shapes of the four corner portions of the die forming the corner portion 11a are the same, the L * values will also be substantially the same. Therefore, for one corner portion 11a, the L * value is measured, and the measurement of the L * values for the other three corner portions 11a can be omitted. a * value and b * The curved surface portion 11 for measuring the value is the same as the curved surface portion 11 for measuring the L * value.

[0030] Also, depending on the shape of the die, etc., for example, even in the case of a rectangular concave portion in plan view as shown in the schematic diagrams of FIGS. 5 and 6, among the curved surface portions 11, the ridge line portion 11b protruding toward the base material layer 1 side may be the portion where it is most extended. For example, on the surface on the base material layer 1 side described above, when the radius of curvature R of the ridge line portion 11b is smaller than the radius of curvature R of the corner portion 11a, among the curved surface portions 11, the ridge line portion 11b protruding toward the base material layer 1 side may be the portion where it is most extended. In such a case, it is preferable to be the object of L * value measurement for the ridge line portion 11b. Also, for example, in the case of a circular concave portion in plan view, since there is no corner portion, the ridge line portion is the object of L * value measurement. Note that the curved surface portion 13 in FIG. 6 is a curved surface portion that does not protrude toward the base material layer 1 side. Compared with the curved surface portion 11 on the side that protrudes toward the base material layer 1 side, generally, the stretching by molding is usually small, and L * it may or may not be adopted as the curved surface portion 11 that is the object of value measurement.

[0031] Also, for the L * value of the non-curved surface portion, it is preferable to measure the portion that is not substantially stretched by molding as the non-curved surface portion 12. The L * value of the non-curved surface portion is usually the same at any position. However, for example, when observing the concave portion 100 from the base material layer 1 side, taking the central portion of the concave portion 100 as the non-curved surface portion 12, it is preferable to measure the L * value.

[0032] In the quality control method of the present disclosure, the L value of the curved surface portion 11 and the L value of the non-curved surface portion 12 of the exterior material 10 for a power storage device, which are the objects of quality control, are not particularly limited. From the viewpoints of whitening and electrolyte resistance as described above, the difference between these L values may be appropriately controlled. For example, when the exterior material 10 for a power storage device is colored (specifically, at least one layer (for example, the base material layer 1, the adhesive layer 2, the colored layer, the surface coating layer 6, etc.) among the layers located on the base material layer 1 side rather than the barrier layer 3 of the exterior material 10 for a power storage device is colored, and when observing the exterior material 10 for a power storage device from the base material layer 1 side, a color different from that of the barrier layer 3 is visually recognized), whitening and the like in the curved surface portion 11 are likely to be determined as defective products. In particular, when the appearance of the exterior material 10 for a power storage device is a dark color such as black, the quality control method of the present disclosure is preferably used. * Regarding the L value of the non-curved surface portion 12, * it is not particularly limited, and from the viewpoints such as whitening and electrolyte resistance as described above, the difference between these L values may be appropriately controlled. * For example, when the exterior material 10 for a power storage device is colored (specifically, at least one layer (for example, the base material layer 1, the adhesive layer 2, the colored layer, the surface coating layer 6, etc.) among the layers located on the base material layer 1 side rather than the barrier layer 3 of the exterior material 10 for a power storage device is colored, and when observing the exterior material 10 for a power storage device from the base material layer 1 side, a color different from that of the barrier layer 3 is visually recognized), whitening and the like in the curved surface portion 11 are likely to be determined as defective products. In particular, when the appearance of the exterior material 10 for a power storage device is a dark color such as black, the quality control method of the present disclosure is preferably used.

[0033] From such a viewpoint, the L value of the non-curved surface portion 12 of the exterior material 10 for a power storage device, which is the object of quality control, * is preferably about 60.0 or less, more preferably about 50.0 or less, still more preferably about 40.0, and even more preferably about 30.0 or less. The L value of the non-curved surface portion 12 * is, for example, about 0.0 or more, about 10.0 or more, about 20.0 or more, etc. The preferable range of the L value of the non-curved surface portion 12 * includes about 0.0 to 60.0, about 0.0 to 50.0, about 0.0 to 40.0, about 0.0 to 30.0, about 10.0 to 60.0, about 10.0 to 50.0, about 10.0 to 40.0, about 10.0 to 30.0, about 20.0 to 60.0, about 20.0 to 50.0, about 20.0 to 40.0, about 20.0 to 30.0. Similarly, the a value of the non-curved surface portion 12 * is, for example, about +2.00 or less, preferably about +1.00 or less. Also, the a value of the non-curved surface portion 12 * is, for example, about -2.00 or more, preferably about -1.00 or more. The a value of the non-curved surface portion 12 *Preferable ranges of the value include about -2.00 to +2.00, about -2.00 to +1.00, about -1.00 to +2.00, about -1.00 to +1.00, and the like. Similarly, the b * value of the non-curved surface portion 12 is, for example, about +1.00 or less, preferably about +0.00 or less. Also, the b * value of the non-curved surface portion 12 is, for example, about -3.00 or more, preferably about -2.00 or more. The b * preferable ranges of the value include about -3.00 to +1.00, about -3.00 to +0.00, about -2.00 to +1.00, about -2.00 to +0.00, and the like.

[0034] Regarding the difference between the L * value of the curved surface portion 11 and the L * value of the non-curved surface portion 12, for example, by adjusting the composition, thickness, etc. of the layer (for example, the base material layer 1, the surface coating layer 6, etc. described later) located in the outermost layer of the exterior material 10 for the power storage device, the shape, size, surface roughness, etc. of the mold, and further the pressing pressure of the mold, it is adjusted to a predetermined value. Also, as described later, by adjusting the lamination conditions of each layer in the lamination process of the exterior material 10 for the power storage device, the difference between the L * value of the curved surface portion 11 and the L * value of the non-curved surface portion 12 may be adjusted.

[0035] Further, for example, when the exterior material for a power storage device has a matte finish, whitening or the like on the curved surface portion 11 is likely to be determined as a defective product, so the quality control method of the present disclosure is preferably used. From such a viewpoint, as the specular glossiness of the non-curved surface portion 12 of the exterior material 10 for a power storage device that is the object of quality control, for example, about 5.0 or less is preferable, and about 3.6 or less is more preferable. Note that the specular glossiness is, for example, about 1.0 or more. Preferable ranges of the specular glossiness include about 1.0 to 5.0 and about 1.0 to 3.6. The specular glossiness of the non-curved surface portion 12 of the exterior material 10 for a power storage device is specified as follows. Note that the specular glossiness of the non-curved surface portion of the exterior material for a power storage device in which a concave portion is formed is substantially the same as the specular glossiness of the outer surface of the exterior material for a power storage device before molding (the position that becomes the non-curved surface portion after molding) (that is, in the non-curved surface portion, the specular glossiness does not substantially change due to molding. For example, when observing the concave portion 100 from the base material layer 1 side, it is preferable to measure the specular glossiness with the central portion of the concave portion 100 as the non-curved surface portion 12). Therefore, when the exterior material for a power storage device before molding is available, the specular glossiness of the outer surface of the exterior material for a power storage device before molding may be measured by the following measurement method.

[0036] <Measurement of specular glossiness> The specular glossiness of the outer surface of the non-curved surface portion of the exterior material for a power storage device is measured by the following measurement method. In accordance with the method specified in JIS Z 8741 (1997), using a gloss meter (for example, Micro-Tri-Gloss made by Toyo Seiki Seisakusho Co., Ltd. with a measurement area of 9 mm × 15 mm), the specular glossiness of the surface coating layer at an incident angle of 60 degrees is measured.

[0037] As described above, the quality control method of the present disclosure is for the L of the curved surface portion and the non-curved surface portion that form the concave portion in the molding process of the exterior material for a power storage device. *A novel quality control method includes a determination step of determining whether an exterior material for a power storage device with recesses formed therein is a good product based on the magnitude of values. Compared with conventional quality control using visual inspection or a camera, it is also possible to perform higher-precision quality control. Therefore, by using the quality control method of the present disclosure in the manufacture of a power storage device, it becomes possible to more efficiently manufacture good products of the power storage device. The determination step can be used, for example, as a determination method for evaluating the characteristics (molding characteristics) of the exterior material for a power storage device based on whether the exterior material for a power storage device is one in which fine cracks are formed in the layer constituting the exterior material for a power storage device due to molding when forming the recesses. By using this determination method, the characteristics of the exterior material for a power storage device can be easily evaluated without using a scanning electron microscope or the like.

[0038] 2. Method for manufacturing a storage device The manufacturing method of the power storage device of the present disclosure is a manufacturing method of a power storage device in which a power storage device element is sealed by a package formed by heat-sealing a heat-sealable resin layer 4 at the periphery (for example, the peripheral portion 14 in FIGS. 5 and 6) of an exterior material 10 for a power storage device composed of a laminate including at least a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4 in this order from the outside. The manufacturing method of the power storage device of the present disclosure is one that uses the quality control method described in the section of "1. Quality control method" in the manufacture of a power storage device, and descriptions of overlapping matters will be omitted as appropriate. Also, as described above, the laminated configuration of the exterior material for a power storage device and the details of each layer will be described later.

[0039] In the manufacturing method of the power storage device of the present disclosure, a step of preparing an exterior material for a power storage device in which a recess is formed so that the power storage device element is accommodated so as to protrude from the heat-sealable resin layer side to the base material layer side of the exterior material for a power storage device is provided. The exterior material for a power storage device with such a recess formed therein is as described in the section of "1. Quality control method", and the description will be omitted.

[0040] In addition, in the manufacturing method of the electricity storage device disclosed herein, a test electricity storage device packaging material is extracted from the electricity storage device packaging materials having a recess formed therein, and the L of reflected light is measured for the curved and non-curved portions of the outer surface that form the recess of the test electricity storage device packaging material under the measurement conditions of the SCI method, a field of view of 10°, and a light source F2. * a * b * L in color space * Measure the value and * The method further includes a determination step of determining whether or not the electrical storage device exterior material in which the recesses are formed is a non-defective product based on the magnitude of the difference in values. The determination step is also as explained in the section "1. Quality control method" above, and therefore further explanation will be omitted. Note that if the electrical storage device exterior material in which the recesses are formed is determined to be a defective product in the determination step of the electrical storage device manufacturing method of the present disclosure, the process returns to the lamination step of the electrical storage device exterior material or the molding step of the electrical storage device exterior material, and the configuration, lamination method, molding conditions, etc. of the electrical storage device exterior material are adjusted until the electrical storage device exterior material is determined to be a non-defective product in the determination step.

[0041] The method for manufacturing an electricity storage device according to the present disclosure includes a step of manufacturing an electricity storage device by accommodating an electricity storage device element in a recess of an electrical storage device exterior material. In the method for manufacturing an electricity storage device according to the present disclosure, if the determination step determines that the electrical storage device exterior material in which the recess is formed is a non-defective product, it is determined that the formation of the recess is appropriate, and an electricity storage device element is accommodated in the recess to manufacture the electricity storage device.

[0042] As mentioned above, L * The evaluation criteria for the difference in the values can be set appropriately depending on the quality required for the electricity storage device. For example, from the viewpoint of controlling whitening in the curved surface portion 11, the L * value and L of the non-curved surface portion 12 * The absolute value of the difference from the value (the absolute value of the difference that is judged to be a non-defective product) is preferably 2.0 or less, more preferably 1.8 or less, even more preferably 1.5 or less, even more preferably 1.0 or less, still more preferably 0.5 or less, and particularly preferably 0.3 or less. *The value and the L of the non-curved surface portion 12 * Preferable ranges of the absolute value of the difference between the value and the value include about 0.0 to 2.0, about 0.0 to 1.8, about 0.0 to 1.5, about 0.0 to 1.0, about 0.0 to 0.5, and about 0.0 to 0.3.

[0043] Also, as described above, from the viewpoint of performing quality control so that a power storage device excellent in electrolytic solution resistance is manufactured, in the determination step, the L of the curved surface portion 11 * The value and the L of the non-curved surface portion 12 * The absolute value of the difference between the values (the absolute value of the difference determined to be a good product) is preferably controlled under conditions stricter than the above whitening, preferably 1.5 or less, more preferably 1.0 or less, still more preferably 0.5 or less, and particularly preferably 0.3 or less. Note that the L of the curved surface portion 11 * The value and the L of the non-curved surface portion 12 * The absolute value of the difference between the values is 0.0 or more. The L of the curved surface portion 11 * The value and the L of the non-curved surface portion 12 * Preferable ranges of the absolute value of the difference between the values include about 0.0 to 1.5, about 0.0 to 1.0, about 0.0 to 0.5, and about 0.0 to 0.3. Also, from the same viewpoint, the a of the curved surface portion 11 * The value and the a of the non-curved surface portion 12 * Preferable ranges of the absolute value of the difference between the values (that is, the absolute value and the absolute value of the difference determined to be a good product) include about 0.00 to 0.12. From the same viewpoint, the b of the curved surface portion * The value and the b of the non-curved surface portion * Preferable ranges of the absolute value of the difference between the values (that is, the absolute value and the absolute value of the difference determined to be a good product) include about 0.00 to 0.60.

[0044] A method of manufacturing a power storage device by housing a power storage device element in the concave portion 100 can apply a known method. Specifically, electrodes, electrolytic solution, etc. constituting the power storage device element are housed in the concave portion 100, and the heat-fusible resin layers 4 of the power storage device exterior material 10 are heat-sealed to seal the power storage device element and obtain a power storage device.

[0045] 3. Inspection method The inspection method of the present disclosure is a method for inspecting an electrical storage device packaging material having a recess formed therein. The inspection method of the present disclosure inspects an electrical storage device packaging material that is composed of a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-sealable resin layer, and that is molded so as to protrude from the heat-sealable resin layer side toward the base material layer side, and that has a recess formed on the heat-sealable resin layer side in which an electrical storage device element is housed. The quality control method of the present disclosure described above can be said to be a quality control method that utilizes the inspection method of the present disclosure, and explanations of matters that overlap with those described in the section "1. Quality Control Method" above will be omitted as appropriate. As mentioned above, the laminate structure and each layer of the electrical storage device packaging material will be described in detail below.

[0046] In the inspection method of the present disclosure, the packaging material for an electricity storage device having recesses formed therein that is the subject of inspection is as explained in the section "1. Quality control method" above, and therefore further explanation will be omitted.

[0047] In addition, in the inspection method of the present disclosure, the curved and non-curved portions of the outer surface that form the recesses of the exterior material for an electricity storage device having recesses are measured using the SCI method, a field of view of 10°, and a light source F2, and the L of reflected light is measured. * a * b * L in color space * Measure the value and * The method further includes a determination step of determining whether the electrical storage device packaging material having recesses formed therein is a non-defective product based on the magnitude of the difference in the values. The determination step is also as described above in the section "1. Quality control method," and therefore, further description thereof will be omitted.

[0048] As mentioned above, L * The evaluation criteria for the difference in the values can be set appropriately depending on the quality required for the electricity storage device. For example, from the viewpoint of controlling whitening in the curved surface portion 11, the L * value and L of the non-curved surface portion 12 *The absolute value of the difference from the value (the absolute value of the difference that is judged to be a non-defective product) is preferably 2.0 or less, more preferably 1.8 or less, even more preferably 1.5 or less, even more preferably 1.0 or less, still more preferably 0.5 or less, and particularly preferably 0.3 or less. * value and L of the non-curved surface portion 12 * Preferred ranges for the absolute value of the difference from the value include about 0.0 to 2.0, about 0.0 to 1.8, about 0.0 to 1.5, about 0.0 to 1.0, about 0.0 to 0.5, and about 0.0 to 0.3.

[0049] As described above, from the viewpoint of quality control so that an electricity storage device having excellent electrolyte resistance is manufactured, the L of the curved surface portion 11 is determined in the determination step. * value and L of the non-curved surface portion 12 * The absolute value of the difference between the L value and the L value (the absolute value of the difference that determines that the product is good) is preferably controlled under stricter conditions than the whitening condition, and is preferably 1.5 or less, more preferably 1.0 or less, even more preferably 0.5 or less, and particularly preferably 0.3 or less. * value and L of the non-curved surface portion 12 * The absolute value of the difference between the L value and the L value is 0.0 or more. * value and L of the non-curved surface portion 12 * The preferable range of the absolute value of the difference from the value is about 0.0 to 1.5, about 0.0 to 1.0, about 0.0 to 0.5, or about 0.0 to 0.3. * value and a of the non-curved surface portion 12 * A preferable range of the absolute value of the difference from the value (i.e., the absolute value of the difference that determines that the product is good) is about 0.00 to 0.12. * value and b of the non-curved surface * A preferable range of the absolute value of the difference from the value (that is, the absolute value of the difference that determines that the product is non-defective) is about 0.00 to 0.60.

[0050] 4. Exterior material for a storage device The exterior material 10 for a power storage device of the present disclosure is an exterior material for a power storage device composed of a laminate including at least, in order from the outside, a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4. The exterior material 10 for a power storage device is formed so as to protrude from the heat-sealable resin layer 4 side toward the base material layer 1 side, and includes a recess 100 in which a power storage device element is accommodated on the heat-sealable resin layer 4 side. Further, regarding the curved surface portion 11 and the non-curved surface portion 12 of the outer surface forming the recess of the exterior material 10 for a power storage device, the L of the reflected light is respectively measured under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2. * a * b * In the L in the color space * value, when measured, the L of the curved surface portion 11 * value and the L of the non-curved surface portion 12 * The absolute value of the difference from is 1.5 or less. That is, the exterior material 10 for a power storage device of the present disclosure is among the exterior materials 10 for a power storage device described in the above "1. Quality control method", and the absolute value of the difference between the L of the curved surface portion 11 * value and the L of the non-curved surface portion 12 * from is 1.5 or less. Therefore, the description of the shape and the like of the exterior material 10 for a power storage device is omitted.

[0051] [[ID=,20]]As described above, in a power storage device, if fine cracks are formed in the curved surface portion of the exterior material for a power storage device, depending on the degree of the cracks, when the electrolytic solution adheres to the surface of the exterior material for a power storage device in the manufacturing process of the power storage device, the electrolytic solution may penetrate into the cracks, and the layers constituting the exterior material for a power storage device may peel off. Therefore, the absolute value of the difference between the L of the curved surface portion 11 of the exterior material 10 for a power storage device in which the recess is formed and the L of the non-curved surface portion 12 * value is preferably controlled under conditions stricter than the above whitening. From such a viewpoint, in the exterior material 10 for a power storage device of the present disclosure, the absolute value of the difference between the L of the curved surface portion 11 * value and the L of the non-curved surface portion 12 * value is set to a particularly low value of 1.5 or less. In the exterior material 10 for a power storage device of the present disclosure, the L of the curved surface portion 11 * value and the L of the non-curved surface portion 12 * value and* The absolute value of the difference from the value is preferably 1.0 or less, more preferably 0.5 or less, and particularly preferably 0.3 or less. As described above, the L of the curved surface portion 11 * value and the L of the non-curved surface portion 12 * The absolute value of the difference from the value is 0.0 or more. The L of the curved surface portion 11 * value and the L of the non-curved surface portion 12 * The preferable range of the absolute value of the difference from the value is about 0.0 to 1.5, about 0.0 to 1.0, about 0.0 to 0.5, about 0.0 to 0.3. Also, from the same viewpoint, the a of the curved surface portion 11 * value and the a of the non-curved surface portion 12 * The preferable range of the absolute value of the difference from the value is about 0.00 to 0.12. From the same viewpoint, the b of the curved surface portion * value and the b of the non-curved surface portion * The preferable range of the absolute value of the difference from the value is about 0.00 to 0.60. The preferable L of the curved surface portion 11 and the non-curved surface portion 12 * value, a * value, and b * For the value, these measurement methods, and the details of the measurement locations, they are as described in the above "1. Quality control method".

[0052] Also, in the present disclosure, the outer packaging material 10 for the power storage device before forming the concave portion 100 is formed by molding the outer packaging material for the power storage device so as to protrude from the heat-sealable resin layer 4 side to the base material layer 1 side under the following molding conditions, forming a concave portion for accommodating the power storage device element on the heat-sealable resin layer 4 side, and for the curved surface portion 11 and the non-curved surface portion 12 of the outer surface forming the concave portion of the outer packaging material 10 for the power storage device, respectively, under the measurement conditions of the SCI method, a visual field of 10°, and a light source F2, the L in the color space * a * b * When measuring the L value in the color space * value, it is preferable that the absolute value of the difference between the L value of the curved surface portion 11 and the L of the non-curved surface portion 12 * value is 1.5 or less. The outer packaging material 10 for the power storage device has no concave portion formed as described above, and when a concave portion is formed under predetermined molding conditions, the L of the curved surface portion 11 * value and the L of the non-curved surface portion 12 * value​* The absolute value of the difference from [is] 1.5 or less.

[0053] (Forming conditions) An exterior material for a power storage device is disposed between a molding die (female die) having a diameter of 54.5 mm (TD) × 31.6 mm (MD) and a corresponding molding die (male die) such that the female die side is the base material layer side, the pressing pressure (surface pressure) is 0.25 MPa, cold forming is performed at a forming depth of 3.0 mm, and a rectangular recess is formed in plan view. The clearance between the female die and the male die is 0.5 mm. The surface of the female die has a maximum height roughness (nominal value of Rz) of 0.8 μm as defined in Table 2 of the comparison surface roughness standard piece in Annex 1 of JIS B 0659-1:2002 (reference). The corner R of the female die is 2.0 mm and the ridge line R is 2.5 mm. The surface of the male die has a maximum height roughness (nominal value of Rz) of 3.2 μm as defined in Table 2 of the comparison surface roughness standard piece in Annex 1 of JIS B 0659-1:2002 (reference). The corner R of the male die is 2.0 mm and the ridge line R is 2.0 mm. The corner R and the ridge line R of the male die have a maximum height roughness (nominal value of Rz) of 1.6 μm as defined in Table 2 of the comparison surface roughness standard piece in Annex 1 of JIS B 0659-1:2002 (reference).

[0054] Even in the exterior material 10 for a power storage device before such forming, after forming a recess by the above-described forming conditions, the L * value of the curved surface portion 11 and the L * value of the non-curved surface portion 12, the absolute value of the difference is preferably 1.0 or less, more preferably 0.5 or less, and particularly preferably 0.3 or less. As described above, the L * value of the curved surface portion 11 and the L * value of the non-curved surface portion 12, the absolute value of the difference is 0.0 or more. The L * value of the curved surface portion 11 and the L * value of the non-curved surface portion 12, preferable ranges of the absolute value of the difference include about 0.0 to 1.5, about 0.0 to 1.0, about 0.0 to 0.5, and about 0.0 to 0.3. Also, from the same viewpoint, the a * value of the curved surface portion 11 and the a *As a preferable range of the absolute value of the difference from the value, about 0.00 to 0.12 can be mentioned. From the same viewpoint, b of the curved surface portion * value and b of the non-curved surface portion * As a preferable range of the absolute value of the difference from the value, about 0.00 to 0.60 can be mentioned. Further, the preferable L of the curved surface portion 11 and the non-curved surface portion 12 * value, a * value, and b * value, the details of these measurement methods and measurement locations are as described in the above "1. Quality control method".

[0055] Laminated structure of the exterior material for a storage device The exterior material 10 for a power storage device is composed of a laminate including at least a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4 in this order, as shown in FIG. 1 for example. In the exterior material 10 for a power storage device, the base material layer 1 is on the outermost layer side, and the heat-sealable resin layer 4 is on the innermost layer. When assembling a power storage device using the exterior material 10 for a power storage device and a power storage device element, the power storage device element is accommodated in a space formed by heat-sealing the peripheral edge portion 14 in a state where the heat-sealable resin layers 4 of the exterior material 10 for a power storage device face each other. In the laminate constituting the exterior material 10 for a power storage device of the present disclosure, with the barrier layer 3 as a reference, the side of the heat-sealable resin layer 4 is inside the barrier layer 3, and the side of the base material layer 1 is outside the barrier layer 3.

[0056] The exterior material 10 for a power storage device may have an adhesive layer 2 between the base material layer 1 and the barrier layer 3 as needed, for example, for the purpose of enhancing the adhesiveness between these layers, as shown in FIGS. 2 to 4. Further, an adhesive layer 5 may be provided between the barrier layer 3 and the heat-sealable resin layer 4 as needed, for example, for the purpose of enhancing the adhesiveness between these layers, as shown in FIGS. 3 and 4. Further, as shown in FIG. 4, a surface coating layer 6 or the like may be provided on the outside of the base material layer 1 (opposite to the heat-sealable resin layer 4 side) as needed.

[0057] The thickness of the laminate constituting the exterior material 10 for the power storage device is not particularly limited, but from the viewpoints of cost reduction, improvement of energy density, etc., it is preferably about 180 μm or less, about 155 μm or less, about 120 μm or less. Further, from the viewpoint of maintaining the function of the exterior material for the power storage device of protecting the power storage device element, the thickness of the laminate constituting the exterior material 10 for the power storage device is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more. Also, regarding the preferable range of the laminate constituting the exterior material 10 for the power storage device, for example, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 180 μm, about 60 to 155 μm, about 60 to 120 μm can be mentioned, and particularly about 60 to 155 μm is preferable.

[0058] In the exterior material 10 for the power storage device, the ratio of the total thickness of the base material layer 1, the adhesive layer 2 provided as necessary, the barrier layer 3, the adhesive layer 5 provided as necessary, the heat-sealable resin layer 4, and the surface coating layer 6 provided as necessary to the thickness (total thickness) of the laminate constituting the exterior material 10 for the power storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. As a specific example, when the exterior material 10 for the power storage device of the present disclosure includes the base material layer 1, the adhesive layer 2, the barrier layer 3, the adhesive layer 5, and the heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the exterior material 10 for the power storage device is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. Also, even when the exterior material 10 for the power storage device of the present disclosure is a laminate including the base material layer 1, the adhesive layer 2, the barrier layer 3, and the heat-sealable resin layer 4, the ratio of the total thickness of these layers to the thickness (total thickness) of the laminate constituting the exterior material 10 for the power storage device can be, for example, 80% or more, preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more.

[0059] [Base material layer 1] In the present disclosure, the base material layer 1 is a layer provided for the purpose of, among other things, functioning as a base material for the exterior material of the power storage device. The base material layer 1 is located on the outer layer side of the exterior material for the power storage device.

[0060] The material forming the base material layer 1 is not particularly limited as long as it has the function of a base material, that is, at least has insulation properties. The base material layer 1 can be formed using, for example, a resin, and the resin may contain additives described later.

[0061] When the base material layer 1 is formed of a resin, the base material layer 1 may be, for example, a resin film formed of a resin, or may be formed by applying a resin. The resin film may be an unstretched film or a stretched film. Examples of the stretched film include a uniaxially stretched film and a biaxially stretched film, and a biaxially stretched film is preferred. Examples of the stretching method for forming the biaxially stretched film include a sequential biaxial stretching method, an inflation method, and a simultaneous biaxial stretching method. Examples of the method for applying the resin include a roll coating method, a gravure coating method, and an extrusion coating method.

[0062] Examples of the resin forming the base material layer 1 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenolic resin, and modified products of these resins. Further, the resin forming the base material layer 1 may be a copolymer of these resins, or a modified product of the copolymer. Furthermore, a mixture of these resins may also be used.

[0063] Among these, the resins preferably used for forming the base material layer 1 include polyester and polyamide.

[0064] Examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolyester, etc. Examples of the copolyester include copolyesters having ethylene terephthalate as the main repeating unit. Specifically, copolyester polyethylenes obtained by polymerizing ethylene terephthalate with ethylene isophthalate (hereinafter abbreviated following polyethylene(terephthalate / isophthalate)), polyethylene(terephthalate / adipate), polyethylene(terephthalate / sodium sulfoisophthalate), polyethylene(terephthalate / sodium isophthalate), polyethylene(terephthalate / phenyl-dicarboxylate), polyethylene(terephthalate / decanedicarboxylate), etc. These polyesters may be used alone or in combination of two or more.

[0065] Examples of the polyamide 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 copolyamides 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, polyamides containing aromatic groups such as polyamide MXD6 (polymetaxylylene adipamide); alicyclic polyamides such as polyamide PACM6 (poly(bis(4-aminocyclohexyl))methane adipamide); furthermore, polyamides copolymerized with lactam components or isocyanate components such as 4,4'-diphenylmethane-diisocyanate, polyesteramide copolymers and polyetheresteramide copolymers which are copolymers of copolyamides with polyesters or polyalkylene ether glycols; and polyamides such as these copolymers. These polyamides may be used alone or in combination of two or more.

[0066] The base material layer 1 preferably contains at least one of a polyester film, a polyamide film, and a polyolefin film, preferably contains at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, and more preferably contains at least one of a stretched polyethylene terephthalate film, a stretched polybutylene terephthalate film, a stretched nylon film, and a stretched polypropylene film. Even more preferably, it contains at least one of a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, a biaxially stretched nylon film, and a biaxially stretched polypropylene film.

[0067] The base material layer 1 may be a single layer or may be composed of two or more layers. When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or may be a laminate of resin films obtained by coextruding resin into two or more layers. Further, the laminate of resin films obtained by coextruding resin into two or more layers may be used as the base material layer 1 as it is without stretching, or may be uniaxially or biaxially stretched to be used as the base material layer 1.

[0068] In the base material layer 1, specific examples of the laminate of two or more resin films include a laminate of a polyester film and a nylon film, a laminate of two or more nylon films, a laminate of two or more polyester films, etc. Preferably, a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more stretched nylon films, and a laminate of two or more stretched polyester films are preferred. For example, when the base material layer 1 is a laminate of two resin films, a laminate of a polyester resin film and a polyester resin film, a laminate of a polyamide resin film and a polyamide resin film, or a laminate of a polyester resin film and a polyamide resin film is preferred, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of a nylon film and a nylon film, or a laminate of a polyethylene terephthalate film and a nylon film is more preferred. Further, since the polyester resin is less likely to change color when, for example, an electrolytic solution adheres to the surface, when the base material layer 1 is a laminate of two or more resin films, it is preferable that the polyester resin film is located in the outermost layer of the base material layer 1.

[0069] When the base material layer 1 is a laminate of two or more resin films, the two or more resin films may be laminated via an adhesive. Preferred adhesives include the same ones as the adhesives exemplified in the adhesive layer 2 described later. Note that the method for laminating two or more resin films is not particularly limited, and a known method can be adopted. For example, a dry lamination method, a sandwich lamination method, an extrusion lamination method, a thermal lamination method, etc. can be mentioned, and preferably, a dry lamination method can be mentioned. When laminating by the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. At this time, the thickness of the adhesive is, for example, about 2 to 5 μm. Also, an anchor coat layer may be formed on the resin film and laminated. The anchor coat layer includes the same ones as the adhesives exemplified in the adhesive layer 2 described later. At this time, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

[0070] Further, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents may be present on at least one of the surface and the interior of the base material layer 1. Only one type of additive may be used, or two or more types may be mixed and used.

[0071] In the present disclosure, from the viewpoint of enhancing the moldability of the exterior material for the power storage device, it is preferable that a lubricant is present on the surface of the base material layer 1. The lubricant is not particularly limited, but preferably an amide-based lubricant. Specific examples of the amide-based lubricant include, for example, saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, aromatic bisamides, and the like. Specific examples of the saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, and the like. Specific examples of the unsaturated fatty acid amides include oleic acid amide, erucic acid amide, and the like. Specific examples of the substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, and the like. Specific examples of the methylol amides include methylol stearic acid amide, and the like. Specific examples of the saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, and the like. Specific examples of the unsaturated fatty acid bisamides include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, and the like. Specific examples of the fatty acid ester amides include stearoamide ethyl stearate, and the like. Specific examples of the aromatic bisamides include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N,N'-distearyl isophthalic acid amide, and the like. The lubricant may be used alone or in combination of two or more.

[0072] When a lubricant is present on the surface of the base material layer 1, the amount of its presence is not particularly limited, but preferably about 3 mg / m 2 or more, more preferably 4 - 15 mg / m 2 or so, even more preferably 5 - 14 mg / m 2 or so.

[0073] The lubricant present on the surface of the base material layer 1 may be one obtained by exuding the lubricant contained in the resin constituting the base material layer 1, or may be one obtained by applying a lubricant to the surface of the base material layer 1.

[0074] Regarding the thickness of the base material layer , it is not particularly limited as long as it exhibits the function of the base material. For example, it may be about 3 - 50 μm, preferably about 10 - 35 μm. When the base material layer 1 is a laminate of two or more resin films, the thickness of each resin film constituting each layer is preferably about 2 - 25 μm, respectively.

[0075] [Adhesive layer 2] In the exterior material for a power storage device of the present disclosure, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as needed for the purpose of enhancing the adhesiveness therebetween.

[0076] The adhesive layer 2 is formed by an adhesive capable of adhering the base material layer 1 and the barrier layer 3. The adhesive used for forming the adhesive layer 2 is not limited, and it may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot press type, etc. Also, it may be a two - component curing adhesive (two - component adhesive), a one - component curing adhesive (one - component adhesive), or a resin without a curing reaction. Further, the adhesive layer 2 may be a single layer or a multi - layer.

[0077] Specific examples of the adhesive components contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolyester; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolyamide; polyolefin resins such as polyolefin, cyclic polyolefin, acid-modified polyolefin, and acid-modified cyclic polyolefin; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resin and melamine resin; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, a polyurethane adhesive is preferably mentioned. In addition, the resins serving as these adhesive components can enhance the adhesive strength by using an appropriate curing agent in combination. The curing agent is appropriately selected from polyisocyanates, polyfunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, etc., according to the functional groups of the adhesive components.

[0078] Examples of the polyurethane adhesive include a polyurethane adhesive containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferably, a two-component curing type polyurethane adhesive using a polyol such as polyester polyol, polyether polyol, and acrylic polyol as the main agent and an aromatic or aliphatic polyisocyanate as the curing agent can be mentioned. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group not only at the terminal of the repeating unit but also in the side chain. Examples of the curing agent include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. Examples of the isocyanate compound include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate (NDI), etc. Further, examples include polyfunctional isocyanate modified products derived from one or more of these diisocyanates. Also, a multimer (for example, a trimer) can be used as the polyisocyanate compound. Examples of such multimers include adducts, biurets, and nurates. By forming the adhesive layer 2 with a polyurethane adhesive, excellent electrolyte resistance is imparted to the exterior material for the power storage device, and peeling of the base material layer 1 is suppressed even when the electrolyte adheres to the side surface.

[0079] Further, the adhesive layer 2 allows the addition of other components as long as the adhesiveness is not inhibited, and may contain a colorant, a thermoplastic elastomer, a tackifier, a filler (including particles), etc. By the adhesive layer 2 containing a colorant, the exterior material for the power storage device can be colored. As the colorant, known ones such as pigments and dyes can be used. Also, only one type of colorant may be used, or two or more types may be mixed and used.

[0080] As described above, for example, when the exterior material 10 for a power storage device is colored (specifically, among the layers located on the substrate layer 1 side of the barrier layer 3 of the exterior material 10 for a power storage device, at least one layer (for example, the substrate layer 1, the adhesive layer 2, the colored layer, the surface coating layer 6, etc., which will be described later) is colored, so that when the exterior material 10 for a power storage device is observed from the substrate layer 1 side, a color different from that of the barrier layer 3 is visually recognized), whitening or the like in the curved surface portion 11 is likely to be determined as a defective product. In particular, when the appearance of the exterior material 10 for a power storage device is a dark color such as black, the quality control method of the present disclosure is effective. Therefore, it is preferable that the adhesive layer 2 of the exterior material 10 for a power storage device is colored.

[0081] The type of the pigment is not particularly limited as long as it does not impair the adhesiveness of the adhesive layer 2. Examples of the organic pigment include pigments such as azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments. Examples of the inorganic pigment include pigments such as carbon black-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments. In addition, fine powders of mica (muscovite), fish scale foil, etc. are included.

[0082] Among the colorants, for example, in order to make the appearance of the exterior material for a power storage device black, carbon black is preferable.

[0083] The average particle diameter of the pigment is not particularly limited, and for example, it is about 0.05 to 5 μm, preferably about 0.08 to 2 μm. The average particle diameter of the pigment is the median diameter measured by a laser diffraction / scattering particle size distribution measuring device.

[0084] The content of the pigment in the adhesive layer 2 is not particularly limited as long as the exterior material for a power storage device is colored, and for example, it is about 5 to 60% by mass, preferably 10 to 40% by mass.

[0085] The thickness of the adhesive layer 2 is not particularly limited as long as the base material layer 1 and the barrier layer 3 can be adhered. For example, it is about 1 μm or more, about 2 μm or more. Also, the thickness of the adhesive layer 2 is, for example, about 10 μm or less, about 5 μm or less. Further, preferred ranges of the thickness of the adhesive layer 2 include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[0086] [Coloring layer] The coloring layer is a layer provided between the base material layer 1 and the barrier layer 3 as needed (illustration is omitted). When having the adhesive layer 2, a coloring layer may be provided between the base material layer 1 and the adhesive layer 2, and between the adhesive layer 2 and the barrier layer 3. Also, a coloring layer may be provided outside the base material layer 1. By providing the coloring layer, the exterior material for the power storage device can be colored. A colored adhesive layer 2 and a coloring layer may be provided between the base material layer 1 and the barrier layer 3.

[0087] The coloring layer can be formed, for example, by applying an ink containing a coloring agent to the surface of the base material layer 1 or the surface of the barrier layer 3. As the coloring agent, known ones such as pigments and dyes can be used. Also, only one type of coloring agent may be used, or two or more types may be mixed and used.

[0088] Specific examples of the coloring agent contained in the coloring layer are the same as those exemplified in the column of [adhesive layer 2].

[0089] [Barrier layer 3] In the exterior material for the power storage device, the barrier layer 3 is a layer that at least suppresses the ingress of moisture.

[0090] Examples of the barrier layer 3 include a metal foil having barrier properties, a vapor deposition film, a resin layer, etc. Examples of the vapor deposition film include a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, etc. Examples of the resin layer include polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having a fluoroalkyl group, and fluorine-containing resins such as polymers mainly composed of fluoroalkyl units, ethylene-vinyl alcohol copolymers, etc. Further, examples of the barrier layer 3 also include a resin film provided with at least one layer of these vapor deposition films and resin layers. A plurality of barrier layers 3 may be provided. The barrier layer 3 preferably includes a layer made of a metal material. Specific examples of the metal material constituting the barrier layer 3 include aluminum alloy, stainless steel, titanium steel, steel plate, etc. When used as a metal foil, it preferably includes at least one of an aluminum alloy foil and a stainless steel foil.

[0091] From the perspective of improving the formability of the exterior material for the power storage device, the aluminum alloy foil is more preferably a soft aluminum alloy foil composed of, for example, an annealed aluminum alloy, and from the perspective of further improving the formability, it is preferably an aluminum alloy foil containing iron. In the aluminum alloy foil containing iron (100% by mass), the content of iron is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. When the iron content is 0.1% by mass or more, an exterior material for the power storage device having better formability can be obtained. When the iron content is 9.0% by mass or less, an exterior material for the power storage device having better flexibility can be obtained. Examples of the soft aluminum alloy foil include aluminum alloy foils having compositions defined in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Also, silicon, magnesium, copper, manganese, etc. may be added as necessary. The softening can be performed by annealing treatment or the like.

[0092] In addition, examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation hardening stainless steel foils. Further, from the perspective of providing an exterior material for the power storage device with excellent formability, the stainless steel foil is preferably composed of austenitic stainless steel.

[0093] Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, SUS316L, etc. Among these, SUS301 or SUS304 is particularly preferable.

[0094] In the case of a metal foil, the thickness of the barrier layer 3 only needs to exhibit a function as a barrier layer that at least suppresses the intrusion of moisture. For example, it can be about 9 to 200 μm. The thickness of the barrier layer 3 is preferably about 85 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, and particularly preferably about 35 μm or less. Also, the thickness of the barrier layer 3 is preferably about 10 μm or more, still more preferably about 20 μm or more, and more preferably about 25 μm or more. Also, as a preferable range of the thickness of the barrier layer 3, there can be mentioned about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, about 25 to 35 μm. When the barrier layer 3 is composed of an aluminum alloy foil, the above-mentioned range is particularly preferable. Also, particularly when the barrier layer 3 is composed of a stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, still more preferably about 30 μm or less, and particularly preferably about 25 μm or less. Also, the thickness of the stainless steel foil is preferably about 10 μm or more, more preferably about 15 μm or more. Also, as a preferable range of the thickness of the stainless steel foil, there can be mentioned about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, about 15 to 25 μm.

[0095] Further, when the barrier layer 3 is a metal foil, it is preferable to provide a corrosion-resistant film on at least the surface opposite to the base material layer in order to prevent dissolution and corrosion. The barrier layer 3 may be provided with corrosion-resistant films on both sides. Here, the corrosion-resistant film refers to, for example, a thin film that is formed by performing a hydrothermal transformation treatment such as boehmite treatment, a chemical conversion treatment, an anodizing treatment, a plating treatment such as nickel or chromium, or a corrosion prevention treatment of applying a coating agent on the surface of the barrier layer to impart corrosion resistance to the barrier layer. As the treatment for forming the corrosion-resistant film, one type may be performed, or two or more types may be combined. Further, not only a single layer but also a multilayer structure can be formed. Furthermore, among these treatments, the hydrothermal transformation treatment and the anodizing treatment are treatments that dissolve the surface of the metal foil with a treatment agent and form a metal compound excellent in corrosion resistance. Note that these treatments may be included in the definition of the chemical conversion treatment. When the barrier layer 3 is provided with a corrosion-resistant film, the barrier layer 3 includes the corrosion-resistant film.

[0096] The corrosion-resistant film prevents delamination between the barrier layer (for example, an aluminum alloy foil) and the base material layer during the molding of the exterior material for the power storage device, and prevents dissolution and corrosion of the surface of the barrier layer due to hydrogen fluoride generated by the reaction of the electrolyte and moisture. In particular, when the barrier layer is an aluminum alloy foil, it prevents dissolution and corrosion of aluminum oxide present on the surface of the barrier layer, and improves the adhesiveness (wettability) of the surface of the barrier layer, showing the effect of preventing delamination between the base material layer and the barrier layer during heat sealing and preventing delamination between the base material layer and the barrier layer during molding.

[0097] As the corrosion-resistant film formed by chemical conversion treatment, various types are known. Mainly, there are corrosion-resistant films containing at least one of phosphates, chromates, fluorides, triazine thiol compounds, and rare earth oxides. Examples of chemical conversion treatments using phosphates and chromates include chromic acid chromate treatment, phosphoric acid chromate treatment, phosphoric acid-chromate treatment, chromate treatment, etc. Examples of chromium compounds used in these treatments include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, dichromic acid chromium, acetylacetate chromium, chromium chloride, potassium sulfate chromium, etc. Examples of phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid, etc. Examples of chromate treatments include etching chromate treatment, electrolytic chromate treatment, coating type chromate treatment, etc., and the coating type chromate treatment is preferred. This coating type chromate treatment involves first degreasing at least the inner layer side surface of the barrier layer (e.g., aluminum alloy foil) by well-known treatment methods such as alkaline immersion method, electrolytic cleaning method, acid cleaning method, electrolytic acid cleaning method, acid activation method, etc. Then, a treatment liquid mainly composed of metal phosphates such as chromium (Cr) phosphate, titanium (Ti) phosphate, zirconium (Zr) phosphate, zinc (Zn) phosphate, etc. and mixtures of these metal salts, or a treatment liquid mainly composed of non-metal phosphates and mixtures of these non-metal salts, or a treatment liquid composed of a mixture of these and synthetic resin, etc. is applied by well-known coating methods such as roll coating method, gravure printing method, immersion method, etc. and dried. For the treatment liquid, various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, ether-based solvents, etc. can be used, and water is preferred. Examples of the resin component used at this time include polymers such as phenolic resins and acrylic resins, and chromate treatment using an aminophenol polymer having repeating units represented by the following general formulas (1) to (4). In the aminophenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more types.The acrylic resin is preferably a derivative such as polyacrylic acid, an acrylic acid-methacrylic acid ester copolymer, an acrylic acid-maleic acid copolymer, an acrylic acid-styrene copolymer, or their sodium salts, ammonium salts, amine salts, etc. In particular, derivatives of polyacrylic acid such as ammonium salts, sodium salts, or amine salts of polyacrylic acid are preferred. In the present disclosure, polyacrylic acid means a polymer of acrylic acid. Further, the acrylic resin is also preferably a copolymer of acrylic acid and a dicarboxylic acid or dicarboxylic anhydride, and is also preferably an ammonium salt, sodium salt, or amine salt of a copolymer of acrylic acid and a dicarboxylic acid or dicarboxylic anhydride. The acrylic resin may be used alone or in combination of two or more.

[0098]

Chemical formula

[0099]

Chemical formula

[0100]

Chemical formula

[0101]

Chemical formula

[0102] In 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. Also, R 1 and R 2 each independently represent the same or different hydroxy groups, alkyl groups, or hydroxyalkyl groups. In general formulas (1) to (4), X, R 1 and R 2Examples of the alkyl group represented by include linear or branched alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, and tert-butyl group. Further, the hydroxyalkyl group represented by X, R 1 and R 2 Examples of the hydroxyalkyl group represented by include linear or branched alkyl groups having 1 to 4 carbon atoms with one hydroxy group substituted, such as hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, and 4-hydroxybutyl group. In General Formulas (1) to (4), the alkyl groups and hydroxyalkyl groups represented by X, R 1 and R 2 may be the same or different from each other. In 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 General Formulas (1) to (4) is preferably about 500 to 1,000,000, more preferably about 1,000 to 20,000. The aminated phenol polymer is produced, for example, by polycondensing a phenol compound or a naphthol compound and formaldehyde to produce a polymer composed of the repeating units represented by the above General Formula (1) or General Formula (3), and then introducing a functional group (-CH2NR 1 R 2 ) into the polymer obtained above using formaldehyde and an amine (R 1 R 2 ). The aminated phenol polymer is used alone or in a mixture of two or more.

[0103] As another example of the corrosion-resistant film, there is a thin film formed by a coating-type corrosion prevention treatment in which a coating agent containing at least one selected from the group consisting of rare earth element oxides sols, anionic polymers, and cationic polymers is applied. The coating agent may further contain phosphoric acid or a phosphate, and a crosslinking agent for crosslinking the polymer. In the rare earth element oxide sol, fine particles of a rare earth element oxide (for example, particles having an average particle size of 100 nm or less) are dispersed in a liquid dispersion medium. Examples of the rare earth element oxide include cerium oxide, yttrium oxide, neodymium oxide, lanthanum oxide, etc., and cerium oxide is preferable from the viewpoint of further improving the adhesion. The rare earth element oxides contained in the corrosion-resistant film can be used alone or in combination of two or more. As the liquid dispersion medium of the rare earth element oxide sol, for example, various solvents such as water, alcohol solvents, hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents can be used, and water is preferable. Examples of the cationic polymer include polyethyleneimine, an ion polymer complex composed of polyethyleneimine and a polymer having a carboxylic acid, a primary amine graft acrylic resin obtained by graft polymerizing a primary amine to an acrylic main skeleton, polyallylamine or its derivative, and aminated phenol. Further, as the anionic polymer, it is preferably poly(meth)acrylic acid or its salt, or a copolymer mainly composed of (meth)acrylic acid or its salt. Further, it is preferable that the crosslinking agent is at least one selected from the group consisting of a compound having any functional group of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group and a silane coupling agent. Further, it is preferable that the phosphoric acid or the phosphate is condensed phosphoric acid or condensed phosphate.

[0104] As an example of the corrosion-resistant film, there is one formed by applying, to the surface of a barrier layer, a material in which fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide and barium sulfate are dispersed in phosphoric acid, and performing a baking treatment at 150 °C or higher.

[0105] The corrosion-resistant film may, if necessary, have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated. Examples of the cationic polymer and the anionic polymer include those described above.

[0106] In addition, the analysis of the composition of the corrosion-resistant film can be carried out, for example, using time-of-flight secondary ion mass spectrometry.

[0107] The amount of the corrosion-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited. For example, in the case of performing a coating-type chromate treatment, per 1 m 2 of the surface of the barrier layer 3, it is desirable that the chromic acid compound is contained in an amount of, for example, about 0.5 to 50 mg in terms of chromium, preferably about 1.0 to 40 mg; the phosphorus compound is contained in an amount of, for example, about 0.5 to 50 mg in terms of phosphorus, preferably about 1.0 to 40 mg; and the aminated phenol polymer is contained in an amount of, for example, about 1.0 to 200 mg, preferably about 5.0 to 150 mg.

[0108] The thickness of the corrosion-resistant film is not particularly limited. However, from the viewpoints of the cohesion of the film and the adhesion to the barrier layer or the heat-sealable resin layer, it is preferably about 1 nm to 20 μm, more preferably about 1 nm to 100 nm, and even more preferably about 1 nm to 50 nm. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope or a combination of observation with a transmission electron microscope and energy-dispersive X-ray spectroscopy or electron energy loss spectroscopy. By analyzing the composition of the corrosion-resistant film using time-of-flight secondary ion mass spectrometry, for example, peaks derived from secondary ions composed of Ce, P, and O (for example, at least one of Ce2PO4 + and CePO4 - etc.) and secondary ions composed of, for example, Cr, P, and O (for example, at least one of CrPO2 + and CrPO4 - etc.) are detected.

[0109] The chemical conversion treatment is carried out by applying a solution containing a compound used for forming a corrosion-resistant film onto the surface of the barrier layer by means of a bar coating method, a roll coating method, a gravure coating method, a dipping method, etc., and then heating the barrier layer so that its temperature reaches about 70 to 200 °C. Further, before subjecting the barrier layer to the chemical conversion treatment, the barrier layer may be preliminarily subjected to a degreasing treatment by means of an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, etc. By performing the degreasing treatment in this way, it becomes possible to perform the chemical conversion treatment on the surface of the barrier layer more efficiently. Further, by using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid for the degreasing treatment, it is possible to form not only a degreasing effect on the metal foil but also a fluoride of a passive metal. In such a case, only the degreasing treatment may be performed.

[0110] [Thermally fusible resin layer 4] In the exterior material for a power storage device of the present disclosure, the thermally fusible resin layer 4 corresponds to the innermost layer and is a layer (sealing layer) that exhibits a function of thermally fusing the thermally fusible resin layers to seal the power storage device element during the assembly of the power storage device.

[0111] The resin constituting the thermally fusible resin layer 4 is not particularly limited as long as it is thermally fusible, but resins containing a polyolefin backbone such as polyolefin and acid-modified polyolefin are preferred. The fact that the resin constituting the thermally fusible resin layer 4 contains a polyolefin backbone can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, etc. Further, when the resin constituting the thermally fusible resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when measuring maleic anhydride-modified polyolefin by infrared spectroscopy, peaks derived from maleic anhydride are detected in the vicinity of a wave number of 1760 cm -1 and in the vicinity of a wave number of 1780 cm -1 When the thermally fusible resin layer 4 is a layer composed of maleic anhydride-modified polyolefin, peaks derived from maleic anhydride are detected when measured by infrared spectroscopy. However, if the degree of acid modification is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

[0112] Examples of polyolefins include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene), etc.; propylene-α-olefin copolymers; and terpolymers of ethylene-butene-propylene. Among these, polypropylene is preferred. When it is a copolymer, the polyolefin resin may be a block copolymer or a random copolymer. These polyolefin-based resins may be used alone or in combination of two or more.

[0113] In addition, the polyolefin may be a cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, isoprene, etc. Examples of the cyclic monomer that is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene, etc. Among these, cyclic alkenes are preferred, and norbornene is more preferred.

[0114] The acid-modified polyolefin is a polymer obtained by modifying a polyolefin by block polymerization or graft polymerization with an acid component. As the polyolefin to be acid-modified, the above-mentioned polyolefins, copolymers obtained by copolymerizing a polar molecule such as acrylic acid or methacrylic acid with the above-mentioned polyolefins, or polymers such as crosslinked polyolefins can also be used. Examples of the acid component used for acid modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride, or their anhydrides.

[0115] The acid-modified polyolefin may be an acid-modified cyclic polyolefin. The acid-modified cyclic polyolefin is a polymer obtained by copolymerizing part of the monomers constituting the cyclic polyolefin by replacing them with an acid component, or by block-polymerizing or graft-polymerizing an acid component onto the cyclic polyolefin. The cyclic polyolefin to be acid-modified is the same as described above. Also, the acid component used for the acid modification is the same as the acid component used for the modification of the above polyolefin.

[0116] Preferred acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0117] The heat-sealable resin layer 4 may be formed of a single resin alone, or may be formed of a blend polymer combining two or more resins. Further, the heat-sealable resin layer 4 may be formed of only one layer, but may also be formed of two or more layers with the same or different resins.

[0118] Also, the heat-sealable resin layer 4 may contain a lubricant or the like as necessary. When the heat-sealable resin layer 4 contains a lubricant, the moldability of the exterior material for the power storage device can be enhanced. The lubricant is not particularly limited, and known lubricants can be used. The lubricant may be used alone or in combination of two or more.

[0119] The lubricant is not particularly limited, but preferably includes amide-based lubricants. Specific examples of the lubricant include those exemplified in the base material layer 1. The lubricant may be used alone or in combination of two or more.

[0120] When a lubricant is present on the surface of the heat-sealable resin layer 4, the amount thereof is not particularly limited, but from the viewpoint of enhancing the moldability of the exterior material for the power storage device, it is preferably 10 to 50 mg / m 2 or so, more preferably 15 to 40 mg / m 2 or so.

[0121] The lubricant present on the surface of the heat-sealable resin layer 4 may be one obtained by exuding the lubricant contained in the resin constituting the heat-sealable resin layer 4, or may be one obtained by applying a lubricant to the surface of the heat-sealable resin layer 4.

[0122] Further, the thickness of the heat-sealable resin layer 4 is not particularly limited as long as the heat-sealable resin layers can exhibit the function of heat-sealing to seal the power storage device element. For example, it is about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described later is 10 μm or more, the thickness of the heat-sealable resin layer 4 is preferably about 85 μm or less, and more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 5 described later is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-sealable resin layer 4 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[0123] [Adhesive layer 5] In the exterior material for the power storage device of the present disclosure, the adhesive layer 5 is a layer provided between the barrier layer 3 (or the corrosion-resistant film) and the heat-sealable resin layer 4 as needed to firmly bond them.

[0124] The subsequent layer 5 is formed of a resin capable of adhering the barrier layer 3 and the heat-sealable resin layer 4. As the resin used for forming the adhesive layer 5, for example, the same adhesives as those exemplified for the adhesive layer 2 can be used. Further, from the viewpoint of firmly adhering the adhesive layer 5 and the heat-sealable resin layer 4, it is preferable that the resin used for forming the adhesive layer 5 contains a polyolefin backbone, and examples thereof include the polyolefins and acid-modified polyolefins exemplified for the aforementioned heat-sealable resin layer 4. On the other hand, from the viewpoint of firmly adhering the barrier layer 3 and the adhesive layer 5, it is preferable that the adhesive layer 5 contains an acid-modified polyolefin. Examples of the acid-modifying component include dicarboxylic acids such as maleic acid, itaconic acid, succinic acid, and adipic acid, anhydrides thereof, acrylic acid, methacrylic acid, etc., and maleic anhydride is most preferable in terms of ease of modification and versatility. Further, from the viewpoint of the heat resistance of the exterior material for the power storage device, it is preferable that the olefin component is a polypropylene-based resin, and it is most preferable that the adhesive layer 5 contains maleic anhydride-modified polypropylene.

[0125] Whether the resin constituting the adhesive layer 5 contains a polyolefin backbone can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, etc., and the analysis method is not particularly limited. Further, whether the resin constituting the adhesive layer 5 contains an acid-modified polyolefin, for example, when measuring maleic anhydride-modified polyolefin by infrared spectroscopy, peaks derived from maleic anhydride are detected in the vicinity of a wave number of 1760 cm -1 and in the vicinity of a wave number of 1780 cm -1 . However, if the degree of acid modification is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

[0126] Furthermore, from the viewpoints of durability such as heat resistance and resistance to the content of the exterior material for the power storage device, and ensuring moldability while reducing the thickness, it is more preferable that the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. Examples of the acid-modified polyolefin preferably include those described above.

[0127] Further, the adhesive layer 5 is preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group. Particularly preferably, it is a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. Further, the adhesive layer 5 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. As the polyester, for example, an ester resin produced by the reaction of an epoxy group and a maleic anhydride group, and an amide-ester resin produced by the reaction of an oxazoline group and a maleic anhydride group are preferable. When unreacted products of curing agents such as a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin remain in the adhesive layer 5, the presence of the unreacted products can be confirmed by a method selected from, for example, infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc.

[0128] Further, from the viewpoint of further enhancing the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocyclic ring, a C=N bond, and a C-O-C bond. Examples of the curing agent having a heterocyclic ring include a curing agent having an oxazoline group and a curing agent having an epoxy group. Examples of the curing agent having a C=N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a C-O-C bond include a curing agent having an oxazoline group and a curing agent having an epoxy group. The fact that the adhesive layer 5 is a cured product of a resin composition containing these curing agents can be confirmed by methods such as gas chromatography-mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and X-ray photoelectron spectroscopy (XPS).

[0129] The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively enhancing the adhesion between the barrier layer 3 and the adhesive layer 5, a polyfunctional isocyanate compound is preferably used. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), those obtained by polymerizing or nurating these, mixtures thereof, and copolymers with other polymers. Also, adducts, burettes, isocyanurates, etc. can be mentioned.

[0130] The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

[0131] The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. Also, as commercially available products, for example, the Epocros series manufactured by Nippon Shokubai Co., Ltd. can be mentioned.

[0132] The ratio of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

[0133] Examples of the compound having an epoxy group include, for example, epoxy resins. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by the epoxy groups present in the molecule, and known epoxy resins can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, and even more preferably about 200 to 800. In the first disclosure, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) measured under the conditions using polystyrene as a standard sample.

[0134] Specific examples of the epoxy resin include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, bisphenol F type glycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, and the like. The epoxy resin may be used alone or in combination of two or more.

[0135] The proportion of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Thereby, the adhesiveness between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

[0136] The polyurethane is not particularly limited, and known polyurethanes can be used. The adhesive layer 5 may be, for example, a cured product of a two-component curable polyurethane.

[0137] The proportion of the polyurethane in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Thereby, the adhesiveness between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced in an atmosphere where there are components that induce corrosion of the barrier layer such as an electrolytic solution.

[0138] In addition, when the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin, the acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

[0139] The adhesive layer 5 may contain a modifier having a carbodiimide group.

[0140] The thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, about 5 μm or less. Further, the thickness of the adhesive layer 5 is preferably about 0.1 μm or more, about 0.5 μm or more. Also, as the range of the thickness of the adhesive layer 5, preferably about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, about 0.5 to 5 μm can be mentioned. More specifically, in the case of the adhesive exemplified in the adhesive layer 2 or a cured product of an acid-modified polyolefin and a curing agent, preferably about 1 to 10 μm, more preferably about 1 to 5 μm can be mentioned. Also, in the case of using the resin exemplified in the heat-fusible resin layer 4, preferably about 2 to 50 μm, more preferably about 10 to 40 μm can be mentioned. When the adhesive layer 5 is the adhesive exemplified in the adhesive layer 2 or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, for example, the adhesive layer 5 can be formed by applying the resin composition and curing it by heating or the like. Also, in the case of using the resin exemplified in the heat-fusible resin layer 4, for example, it can be formed by extrusion molding of the heat-fusible resin layer 4 and the adhesive layer 5.

[0141] [Surface coating layer 6] The exterior material for a power storage device of the present disclosure may be provided with a surface coating layer 6 on the upper side of the base material layer 1 (the side opposite to the barrier layer 3 of the base material layer 1) as needed for the purpose of improving at least one of design, electrolyte resistance, scratch resistance, formability, etc. The surface coating layer 6 is a layer located on the outermost layer side of the exterior material for a power storage device when a power storage device is assembled using the exterior material for a power storage device.

[0142] The surface coating layer 6 can be formed of at least one of, for example, resins such as polyvinylidene chloride, polyester, polyurethane, acrylic resin, epoxy resin, polyamide, fluororesin, silicone resin, phenol resin, mixtures of these resins, modified products of these resins, copolymers containing these resins, copolymers containing modified products of these resins, etc. The resin is preferably a curable resin.

[0143] When the resin forming the surface coating layer 6 is a curable resin, the resin may be either a one-component curable type or a two-component curable type, but preferably a two-component curable type. Examples of the two-component curable type resin include two-component curable polyurethane, two-component curable polyester, two-component curable epoxy resin, etc. Among these, two-component curable polyurethane is preferable.

[0144] Examples of two-component curable polyurethanes include polyurethanes containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferably, two-component curable polyurethanes are those in which polyols such as polyester polyols, polyether polyols, and acrylic polyols are used as the main agent and aromatic or aliphatic polyisocyanates are used as the curing agent. In particular, as the polyol, it is preferable to contain two or more of polyester polyols, polyether polyols, and acrylic polyols, and it is more preferable to contain two or more of the three types of polyester polyols, polyether polyols, and acrylic polyols. Also, the polyol preferably contains an acrylic polyol. The curing agent preferably contains an aromatic isocyanate compound. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group not only at the terminal of the repeating unit but also in the side chain. Examples of the curing agent include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. Examples of the isocyanate compound include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate (NDI), etc. Also, examples include polyfunctional isocyanate modified products derived from one or more of these diisocyanates. Further, a multimer (for example, a trimer) can also be used as the polyisocyanate compound. Such multimers include adducts, biurets, nurates, etc. Note that the aliphatic isocyanate compound refers to an isocyanate having an aliphatic group and no aromatic ring, the alicyclic isocyanate compound refers to an isocyanate having an alicyclic hydrocarbon group, and the aromatic isocyanate compound refers to an isocyanate having an aromatic ring. The formation of the surface coating layer 6 from polyurethane imparts excellent electrolyte resistance to the exterior material for the power storage device.

[0145] The surface coating layer 6 may contain additives such as the lubricants, anti-blocking agents, matting agents (fillers (particles, etc.)), flame retardants, antioxidants, tackifiers, antistatic agents, etc. described above, as necessary, depending on at least one of the surface and the interior of the surface coating layer 6 and the functionality to be provided on the surface coating layer 6 and its surface. Examples of the additives include fine particles having an average particle diameter of about 0.5 nm to 5 μm. The average particle diameter of the additives shall be the median diameter measured by a laser diffraction / scattering particle size distribution measuring device.

[0146] The additives may be either inorganic or organic substances. Also, the shape of the additives is not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, scaly, etc.

[0147] Specific examples of the additives include talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high melting point nylon, acrylate resin, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, etc. The additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferably mentioned from the viewpoints of dispersion stability and cost, etc. Also, various surface treatments such as insulation treatment and high dispersibility treatment may be performed on the surface of the additives.

[0148] As described above, for example, when the exterior material 10 for a power storage device is colored (specifically, among the layers located on the base material layer 1 side rather than the barrier layer 3 of the exterior material 10 for a power storage device, at least one layer (for example, the base material layer 1, the adhesive layer 2, the colored layer, the surface coating layer 6, etc. described later) is colored, so that when the exterior material 10 for a power storage device is observed from the base material layer 1 side, a color different from that of the barrier layer 3 is visually recognized), whitening or the like in the curved surface portion 11 is likely to be determined as a defective product. In particular, when the appearance of the exterior material 10 for a power storage device is a dark color such as black, the quality control method of the present disclosure is effective. Further, for example, when the exterior material for a power storage device has a matte finish, whitening or the like in the curved surface portion 11 is likely to be determined as a defective product, so that the quality control method of the present disclosure is effective. Therefore, in the exterior material 10 for a power storage device, the surface coating layer 6 may be colored, or it is preferable that the surface coating layer 6 contains a matting agent. Specifically, the surface coating layer 6 is composed of a resin composition containing a resin (for example, polyurethane formed from a mixture of a polyol compound and an aromatic isocyanate compound), inorganic particles (for example, silica particles, etc.), and organic particles. When the exterior material 10 for a power storage device is observed from the surface coating layer 6 side, when the appearance is a dark black color, the quality control method of the present disclosure is effective.

[0149] The method for forming the surface coating layer 6 is not particularly limited. For example, a method of applying a resin for forming the surface coating layer 6 can be mentioned. When an additive is blended in the surface coating layer 6, a resin mixed with the additive may be applied.

[0150] The thickness of the surface coating layer 6 is not particularly limited as long as the above functions as the surface coating layer 6 are exhibited. For example, it is about 0.5 to 10 μm, preferably about 1 to 5 μm.

[0151] Method for manufacturing the exterior material for a storage device The manufacturing method of the exterior material for a power storage device is not particularly limited as long as a laminate in which each layer included in the exterior material for a power storage device of the present invention is laminated can be obtained. For example, a method including a step of laminating at least the base material layer 1, the barrier layer 3, and the heat-fusible resin layer 4 in this order can be mentioned.

[0152] As an example of the method for manufacturing the exterior material for a power storage device of the present invention, it is as follows. First, a laminate (hereinafter, sometimes referred to as "laminate A") in which a base material layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order is formed. Specifically, the formation of laminate A is carried out by applying an adhesive used for forming the adhesive layer 2 onto the base material layer 1 or, if necessary, onto the barrier layer 3 whose surface has been subjected to a chemical conversion treatment, using a coating method such as a gravure coating method or a roll coating method, drying it, and then laminating the barrier layer 3 or the base material layer 1 and curing the adhesive layer 2 by a dry lamination method.

[0153] Next, a heat-sealable resin layer 4 is laminated onto the barrier layer 3 of laminate A. When directly laminating the heat-sealable resin layer 4 onto the barrier layer 3, it may be laminated onto the barrier layer 3 of laminate A by a method such as a thermal lamination method or an extrusion lamination method. Also, when an adhesive layer 5 is provided between the barrier layer 3 and the heat-sealable resin layer 4, for example, (1) a method of laminating by extruding the adhesive layer 5 and the heat-sealable resin layer 4 onto the barrier layer 3 of laminate A (co-extrusion lamination method, tandem lamination method), (2) separately forming a laminate in which the adhesive layer 5 and the heat-sealable resin layer 4 are laminated and laminating this onto the barrier layer 3 of laminate A by a thermal lamination method, or forming a laminate in which the adhesive layer 5 is laminated onto the barrier layer 3 of laminate A and laminating this with the heat-sealable resin layer 4 by a thermal lamination method, (3) a method of pouring a molten adhesive layer 5 between the barrier layer 3 of laminate A and a heat-sealable resin layer 4 previously formed into a sheet shape and bonding laminate A and the heat-sealable resin layer 4 through the adhesive layer 5 while pouring (sandwich lamination method), (4) a method of solution coating and drying an adhesive for forming the adhesive layer 5 onto the barrier layer 3 of laminate A, and further laminating a heat-sealable resin layer 4 previously formed into a sheet shape onto this adhesive layer 5 by a method such as baking, etc. can be mentioned.

[0154] When providing the surface coating layer 6, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above resin for forming the surface coating layer 6 onto the surface of the base material layer 1. Note that the order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer 6.

[0155] As described above, a laminate including the surface coating layer 6 (provided as necessary) / base material layer 1 / adhesive layer 2 (provided as necessary) / barrier layer 3 / adhesive layer 5 (provided as necessary) / heat-fusible resin layer 4 in this order is formed. However, in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as necessary, it may be further subjected to heat treatment.

[0156] In the exterior material for a power storage device, each layer constituting the laminate may be subjected to a surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment, etc. as necessary to improve the processability. For example, by subjecting the surface of the base material layer 1 opposite to the barrier layer 3 to corona treatment, the printability of ink on the surface of the base material layer 1 can be improved.

[0157] Use of the exterior material for a storage device The exterior material for a power storage device of the present disclosure is used for a package for sealing and housing power storage device elements such as a positive electrode, a negative electrode, and an electrolyte. That is, a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte can be housed in a package formed of the exterior material for a power storage device of the present disclosure to obtain a power storage device.

[0158] Specifically, a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is coated with the exterior material for a power storage device of the present disclosure in a state where metal terminals connected to each of the positive electrode and the negative electrode protrude outward, so that a flange portion (a region where heat-sealable resin layers contact each other) can be formed at the periphery of the power storage device element, and the heat-sealable resin layers of the flange portion are heat-sealed and sealed, thereby providing a power storage device using the exterior material for a power storage device. When the power storage device element is accommodated in a package formed by the exterior material for a power storage device of the present disclosure, the heat-sealable resin portion of the exterior material for a power storage device of the present disclosure is made to be on the inner side (the surface in contact with the power storage device element) to form the package. The heat-sealable resin layers of two exterior materials for a power storage device may be opposed to each other and overlapped, and the peripheral portion of the overlapped exterior materials for a power storage device may be heat-sealed to form a package. Also, as in the example shown in FIG. 11, one exterior material for a power storage device may be folded back and overlapped, and the peripheral portion may be heat-sealed to form a package. When folding back and overlapping, as in the example shown in FIG. 11, sides other than the folded side may be heat-sealed to form a package by three-side sealing, or may be folded back so that a flange portion can be formed and four-side sealed. Further, a recess for accommodating the power storage device element may be formed in the exterior material for a power storage device by deep drawing or protrusion forming. As in the example shown in FIG. 11, a recess may be provided in one exterior material for a power storage device and not provided in the other exterior material for a power storage device, or a recess may also be provided in the other exterior material for a power storage device.

[0159] The exterior material for a power storage device of the present disclosure can be suitably used for power storage devices such as batteries (including capacitors, capacitors, etc.). Further, the exterior material for a power storage device of the present disclosure can be used for either a primary battery or a secondary battery, but is preferably used for a secondary battery. There is no particular limitation on the type of secondary battery to which the exterior material for a power storage device of the present disclosure is applied. For example, lithium ion batteries, lithium ion polymer batteries, all-solid-state batteries, lead-acid batteries, nickel-hydrogen storage batteries, nickel-cadmium storage batteries, nickel-iron storage batteries, nickel-zinc storage batteries, silver oxide-zinc storage batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors, etc. can be mentioned. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries can be mentioned as suitable application targets for the exterior material for a power storage device of the present disclosure.

Examples

[0160] Examples are shown below to explain the present disclosure in detail. However, the present disclosure is not limited to the examples.

[0161] <Manufacture of Exterior Material for Power Storage Device> Examples 1 - 6 As the base material layer, a stretched nylon (ONy) film (thickness 15 μm) was prepared. Also, as the barrier layer, an aluminum foil (JIS H4160:1994 A8021H-O (thickness 35 μm)) was prepared. Next, the barrier layer and the base material layer were laminated by the dry lamination method using an adhesive (a two-component urethane adhesive containing carbon black as a colorant), and then an aging treatment was carried out to produce a laminate of the base material layer / adhesive layer (black) / barrier layer. Both sides of the aluminum foil were subjected to a chemical conversion treatment. The chemical conversion treatment of the aluminum foil was carried out by applying a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid to both sides of the aluminum foil by the roll coating method so that the coating amount of chromium was 10 mg / m 2 (dry mass), and baking.

[0162] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness: 20 μm) and random polypropylene as a heat-sealable resin layer (thickness: 15 μm) were co-extruded onto the barrier layer of each laminate obtained above, thereby laminating an adhesive layer / heat-sealable resin layer onto the barrier layer. Further, a resin composition (the resin is a polyurethane resin formed from a mixture of a polyol compound and an isocyanate compound) having the composition described below was applied to the surface of the base material layer of the obtained laminate to a thickness of 3 μm, thereby forming a matte-finish surface coating layer. A laminate (total thickness: 91 μm) was obtained in which a surface coating layer (3 μm) / base material layer (thickness: 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-sealable resin layer (15 μm) were laminated in order from the outside.

[0163] Next, each of the obtained laminates was cut into strip pieces of 150 mm (TD; Transverse Direction) × 90 mm (MD: Machine Direction). Note that the MD of the laminate corresponds to the rolling direction (RD) of the aluminum alloy foil, and the TD of the laminate corresponds to the TD of the aluminum alloy foil. Next, the strip piece was placed between a molding die (female die) having a diameter of 54.5 mm (TD) × 31.6 mm (MD) and a corresponding molding die (male die) (the female die side being the base material layer side), and cold molding was performed using four cylinders (cylinder diameter φ80 mm) with the pressing pressure of the cylinders set to 0.25 MPa and the molding depth D = 3.0 mm, thereby obtaining an exterior material for a power storage device having a rectangular recess 100 in plan view as shown in the schematic diagrams of FIGS. 5 and 6 and having a black appearance.

[0164] The clearance between the female mold and the male mold was set at 0.5 mm. The surface of the female mold has a maximum height roughness (the nominal value of Rz) of 0.8 μm as specified in Table 2 of the reference surface roughness standard piece in Appendix 1 of JIS B 0659-1:2002. The corner R of the female mold is 2.0 mm and the edge line R is 2.5 mm. The surface of the male mold has a maximum height roughness (the nominal value of Rz) of 3.2 μm as specified in Table 2 of the reference surface roughness standard piece in Appendix 1 of JIS B 0659-1:2002. The corner R of the male mold is 2.0 mm and the edge line R is 2.0 mm. The corner R and the edge line R of the male mold have a maximum height roughness (the nominal value of Rz) of 1.6 μm as specified in Table 2 of the reference surface roughness standard piece in Appendix 1 of JIS B 0659-1:2002.

[0165] Example 7 As the base material layer, a stretched nylon (ONy) film (thickness 12 μm) was prepared. Also, as the barrier layer, a stainless steel foil (SUS304 (thickness 20 μm)) was prepared. Next, after laminating the barrier layer and the base material layer by the dry lamination method using an adhesive (a two-component urethane adhesive containing carbon black as a colorant), an aging treatment was carried out to produce a laminate of the base material layer / adhesive layer (black) / barrier layer. Chemical conversion treatment was applied to both sides of the stainless steel foil. The chemical conversion treatment of the stainless steel foil was carried out by applying a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid to both sides of the stainless steel foil by the roll coating method so that the coating amount of chromium became 10 mg / m 2 (dry mass), and baking.

[0166] Next, the barrier layer and the heat-sealable resin layer of the laminate obtained above were adhered by the dry lamination method using a modified olefin-based adhesive (the thickness of the adhesive layer after curing is 3 μm), and the adhesive layer and the heat-sealable resin layer were laminated on the barrier layer. As the heat-sealable resin layer, an unstretched polypropylene film (thickness 23 μm) was used. Further, a resin composition 2 (the resin is a polyurethane resin formed from a mixture of a polyol compound and an isocyanate-based compound) having the composition described below was applied to the surface of the base material layer of the obtained laminate so as to have a thickness of 3 μm, thereby forming a matte-finished surface coating layer. A laminate (total thickness 64 μm) in which a surface coating layer (3 μm) / base material layer (thickness 12 μm) / adhesive layer (3 μm) / barrier layer (20 μm) / adhesive layer (3 μm) / heat-sealable resin layer (23 μm) was laminated in order from the outside was obtained. The obtained laminate was molded in the same manner as in Examples 1 to 6, and an exterior material for a power storage device having a black appearance and having a rectangular recess 100 in plan view as shown in the schematic diagrams of FIGS. 5 and 6 was obtained.

[0167] Example 8 In the formation of the surface coating layer, an exterior material for a power storage device having a black appearance and having a rectangular recess 100 in plan view as shown in the schematic diagrams of FIGS. 5 and 6 was obtained in the same manner as in Example 7, except that the following resin composition 3 was used instead of the resin composition 2 to form the surface coating layer.

[0168] [Resin composition of surface coating layer] In the examples, resin compositions having the following compositions were used for the formation of the surface coating layer, respectively.

[0169] (Resin composition 1 (used in Example 1)) A resin composition containing a resin (a polyurethane formed from a mixture of one polyol compound and an aliphatic isocyanate-based compound), inorganic particles (barium sulfate particles with an average particle diameter of 1 μm), organic particles (average particle diameter of 2 μm), and an olefin-based wax.

[0170] (Resin composition 2 (used in Examples 2 and 7)) A resin composition comprising a resin (a polyurethane formed from a mixture of two polyol compounds and an aliphatic isocyanate compound), inorganic particles (silica particles with an average particle diameter of 1 μm), organic particles (with an average particle diameter of 2 μm), and an olefin wax.

[0171] (Resin composition 3 (used in Examples 3 and 8)) A resin composition comprising a resin (a polyurethane formed from a mixture of two polyol compounds and an aromatic isocyanate compound, with the mixing ratio of the two polyol compounds changed from that in Resin Composition 2), inorganic particles (silica particles with an average particle diameter of 1 μm), and organic particles (with an average particle diameter of 2 μm).

[0172] (Resin composition 4 (used in Example 4)) A product with the inorganic particle content of the resin composition of Example 2 reduced.

[0173] (Resin composition 5 (used in Example 5)) A product with the inorganic particle content of the resin composition of Example 3 reduced.

[0174] (Resin composition 6 (used in Example 6)) A resin composition comprising a resin (a polyurethane formed from a mixture of two polyol compounds and an aromatic isocyanate compound, with the mixing ratio of the two polyol compounds changed from that in the resin composition of Example 3), inorganic particles (silica particles with an average particle diameter of 1 μm), organic particles (with an average particle diameter of 2 μm), and an olefin wax.

[0175] <Judgment step> For each of the curved surface portions on the outer surface of the base material layer forming the recesses of the outer packaging materials for the power storage devices obtained in the examples, on the side of the base material layer of the outer packaging materials for the power storage devices, at the corners of the curved surface portions protruding on the side of the base material layer of the outer packaging materials for the power storage devices (the curved surface portion 11 shown in the schematic diagrams of FIGS. 5 and 6), and for the non-curved surface portions on the outer surface of the base material layer forming the recesses (the non-curved surface portion 12 (the central portion of the recess 100) shown in the schematic diagrams of FIGS. 5 and 6), under the following conditions, L * a * b * L in the color space *Value, a * Value, and b * Values were measured. The observation conditions of the spectrophotometer (CM-700d) manufactured by Konica Minolta, which was calibrated with a white calibration cap (CM-A177: manufactured by Konica Minolta), were set to 10° for the observation angle, F2 for the observation light source, and the SCI mode (JIS Z8722-2009). Next, for the curved surface part and the non-curved surface part, the L value of the outer surface (substrate layer side) was measured respectively. * Value, a * Value, b * Value measurements were performed at normal temperature and humidity. For the curved surface part, the measurement diameter was set to 8 mmφ, and for the non-curved surface part, the measurement diameter was set to 3 mmφ for measurement. Also, the ΔEab value was calculated based on the formula of ΔEab = [(ΔL) + (Δa) + (Δb)]. The results are shown in Table 1. In Table 1, the L value is the value obtained by rounding the second decimal place of the measured value, and the a value and b value are the values obtained by rounding the third decimal place of the measured value respectively. By performing the determination step, it was confirmed that in Examples 1 to 5, 7, and 8, the absolute value of the difference in the L value between the curved surface part and the non-curved surface part was 1.5 or less, and in Example 6, the absolute value of the difference exceeded 1.5. * The value of ΔEab was calculated based on the formula of * ΔEab = [(ΔL) 2 +(Δa) 2 +(Δb) 2 1 / 2 The results are shown in Table 1. In Table 1, the L * value is the value obtained by rounding the second decimal place of the measured value, a * value and b * value are the values obtained by rounding the third decimal place of the measured value respectively. By performing the determination step, it was confirmed that in Examples 1 to 5, 7, and 8, the absolute value of the difference in the L value between the curved surface part and the non-curved surface part was 1.5 or less, and in Example 6, the absolute value of the difference exceeded 1.5. * The absolute value of the difference in the L value between the curved surface part and the non-curved surface part was 1.5 or less. In Example 6, it was confirmed that the absolute value of the difference exceeded 1.5.

[0176] <Observation by Scanning Electron Microscope> Next, for the curved surface part where the L value, a value, and b value were measured in the above <Determination Step>, observation was performed with a scanning electron microscope (magnification 1,000 times). The obtained images are shown in Fig. 7 (Example 1), Fig. 8 (Example 2), Fig. 9 (Example 3), and Fig. 10 (Example 6) respectively. As a result, in the outer packaging materials for power storage devices of Examples 1 to 5 where the absolute value of the difference in the L value was 1.5 or less, no cracks occurred on the curved surface part, and it was possible to determine them as good products. Also, in the outer packaging materials for power storage devices of Examples 7 and 8, no cracks occurred on the curved surface part, and it was possible to determine them as good products. On the other hand, for the outer packaging materials for power storage devices of Examples 7 and 8, no cracks occurred on the curved surface part, and it was possible to determine them as good products. On the other hand, * Value, a * Value, and b * For the curved surface part where the values were measured, observation was performed with a scanning electron microscope (magnification 1,000 times). The obtained images are shown in Fig. 7 (Example 1), Fig. 8 (Example 2), Fig. 9 (Example 3), and Fig. 10 (Example 6) respectively. As a result, in the outer packaging materials for power storage devices of Examples 1 to 5 where the absolute value of the difference in the L value was 1.5 or less, no cracks occurred on the curved surface part, and it was possible to determine them as good products. Also, in the outer packaging materials for power storage devices of Examples 7 and 8, no cracks occurred on the curved surface part, and it was possible to determine them as good products. On the other hand, * In the outer packaging materials for power storage devices of Examples 1 to 5 where the absolute value of the difference in the L value was 1.5 or less, no cracks occurred on the curved surface part, and it was possible to determine them as good products. Also, in the outer packaging materials for power storage devices of Examples 7 and 8, no cracks occurred on the curved surface part, and it was possible to determine them as good products. On the other hand, for the outer packaging materials for power storage devices of Examples 7 and 8, no cracks occurred on the curved surface part, and it was possible to determine them as good products. On the other hand,​* In the case of the exterior material for a power storage device of Example 6 in which the absolute value of the difference in values exceeded 1.5, very fine cracks occurred in the curved surface portion, and in the above-described determination step, it was possible to determine that the product was defective. As described above, L * The fact that the absolute value of the difference in values is 1.5 or less is an example of the determination criterion, and in the quality control method of the present disclosure and the manufacturing method of the power storage device, it is not necessary to adopt the determination criterion. Table 1 shows the results of evaluating the cracks observed with a scanning electron microscope according to the following criteria. A: No cracks occurred. B: Cracks occurred, but each crack was small and the number of cracks was small. C: Cracks occurred, each crack was large, and the number of cracks was very large.

[0177] <Appearance evaluation> In the above <Determination step>, L * value, a * value, and b * For the curved surface portion and the non-curved surface portion where the values were measured, a skilled person in the whitening evaluation by molding of the exterior material for a power storage device visually observed the appearance and evaluated it according to the following criteria. The results are shown in Table 1. A: The appearances of the curved surface portion and the non-curved surface portion are the same. B: Compared with the non-curved surface portion, the curved surface portion is judged to be slightly whitened, but the whitening is at a level that is difficult to judge even for a skilled person. C: Compared with the non-curved surface portion, the curved surface portion is judged to be slightly whitened, but the whitening is at a level that is slightly difficult to judge for a person who is not a skilled person.

[0178] <Measurement of specular glossiness> The specular glossiness of the outer surface of the surface coating layer before molding of each exterior material for a power storage device was measured by the following measurement method. In accordance with the method specified in JIS Z 8741 (1997), the specular glossiness of the surface coating layer at an incident angle of 60 degrees was measured using a gloss meter Micro-Tri-Gloss (measurement area 9 mm × 15 mm) manufactured by Toyo Seiki Seisakusho. The results are shown in Table 1. The specular glossiness described in Table 1 is a value obtained by rounding the second decimal place of the measured value.

[0179]

Table 1

[0180] From the results of Examples 1 to 8, by applying the quality control method of the present disclosure to the molding process of the exterior material for the power storage device, based on the magnitude of the L value of the curved surface portion and the non-curved surface portion forming the concave portion, it can be seen that it is possible to determine whether the exterior material for the power storage device with the concave portion formed is a good product. Such a quality control method is a novel quality control method, and compared with the conventional quality control using visual inspection or a camera, it can perform higher-precision quality control. Therefore, by using the quality control method of the present disclosure in the manufacture of the power storage device, it becomes possible to more efficiently manufacture good products of the power storage device. In the observation by a scanning electron microscope, those with a crack evaluation of B had small cracks and a small number of cracks in the curved surface portion, so the cracks were not continuous and the surface coating layer existed as a film. On the other hand, those with a crack evaluation of C had large cracks and a large number of cracks, so the cracks in the curved surface portion were continuous, the surface coating layer existed in an island shape, and it was in a state where it was likely to peel off. * From the results of Examples 1 to 8, by applying the quality control method of the present disclosure to the molding process of the exterior material for the power storage device, based on the magnitude of the L value of the curved surface portion and the non-curved surface portion forming the concave portion, it can be seen that it is possible to determine whether the exterior material for the power storage device with the concave portion formed is a good product. Such a quality control method is a novel quality control method, and compared with the conventional quality control using visual inspection or a camera, it can perform higher-precision quality control. Therefore, by using the quality control method of the present disclosure in the manufacture of the power storage device, it becomes possible to more efficiently manufacture good products of the power storage device. In the observation by a scanning electron microscope, those with a crack evaluation of B had small cracks and a small number of cracks in the curved surface portion, so the cracks were not continuous and the surface coating layer existed as a film. On the other hand, those with a crack evaluation of C had large cracks and a large number of cracks, so the cracks in the curved surface portion were continuous, the surface coating layer existed in an island shape, and it was in a state where it was likely to peel off.

[0181] <Evaluation of Electrolyte Resistance> In a normal temperature (23 °C) environment, for the outer surface (the outer surface of the surface coating layer) of each molded exterior material for the power storage device obtained in Examples 3, 5, 6, 7, and 8, the L value, a value, and b value were measured for the non-bent portion and the curved surface portion, and an electrolyte solution (1 mol / liter lithium hexafluorophosphate solution, solvent: ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1:1:1 (volume ratio)) was dropped 3 drops each on the non-bent portion and the bent portion. After 20 minutes elapsed, the dropped electrolyte solution was wiped off with a wipe impregnated with isopropyl alcohol (IPA). Next, the curved surface portion was visually observed, and the electrolyte resistance was evaluated according to the following criteria. The results are shown in Table 2. * value, a * value, and b * value, an electrolyte solution (1 mol / liter lithium hexafluorophosphate solution, solvent: ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1:1:1 (volume ratio)) was dropped 3 drops each on the non-bent portion and the bent portion. After 20 minutes elapsed, the dropped electrolyte solution was wiped off with a wipe impregnated with isopropyl alcohol (IPA). Next, the curved surface portion was visually observed, and the electrolyte resistance was evaluated according to the following criteria. The results are shown in Table 2. A: No peeling of the surface coating layer is observed. C: Peeling of the surface coating layer is observed.

[0182] [Table 2]

[0183] The electrical storage device packaging materials produced in Examples 1 to 8 have a matte finish containing inorganic particles in the surface coating layer, and therefore can be said to be electrical storage device packaging materials that are prone to fine cracks due to molding. Despite being such electrical storage device packaging materials, a comparison of the evaluation of electrolyte resistance between Examples 3, 5, 7, and 8 and Example 6 shows that the L of the curved surface * value and L of the non-curved surface 12 * It can be seen that Examples 3, 5, 7 and 8, in which the absolute value of the difference from the value was controlled to 1.5 or less, were particularly excellent in electrolyte resistance.

[0184] As described above, the present disclosure provides the following aspects of the invention. Item 1. A quality control method in a molding process of an exterior material for an electricity storage device, The quality control method targets quality control of an electrical storage device packaging material that is made of a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order from the outside, and that is molded so as to protrude from the heat-sealable resin layer side toward the base material layer side, and that has a recess formed on the heat-sealable resin layer side in which an electrical storage device element is housed, From the packaging materials for electricity storage devices in which the recesses are formed, a packaging material for an electricity storage device to be tested is selected, and the L of reflected light is measured for each of the curved and non-curved portions of the outer surface that form the recesses of the packaging material for an electricity storage device to be tested using the SCI method, a field of view of 10°, and a light source F2. * a * b * L in color space * Measure the value and * a determining step of determining whether or not the electrical storage device packaging material in which the recess is formed is a non-defective product based on the magnitude of the difference between the values. A quality control method for the molding process of exterior materials for electricity storage devices. Item 2. In the determination step, the absolute value of the difference between the L * value of the curved surface portion and the L * value of the non-curved surface portion is 1.5 or less, and the quality control method according to Item 1, which determines that the product is a non-defective product. Item 3. The exterior material for the power storage device includes a surface coating layer on the outside of the base material layer, and the quality control method according to Item 1 or 2. Item 4. The exterior material for the power storage device includes an adhesive layer between the base material layer and the barrier layer, and the adhesive layer is colored, and the quality control method according to any one of Items 1 to 3. Item 5. A method for manufacturing a power storage device in which a power storage device element is sealed by a package formed by heat-sealing a heat-sealable resin layer at the periphery of an exterior material for a power storage device composed of a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order from the outside, The method for manufacturing the power storage device includes a step of preparing an exterior material for a power storage device in which a recess for accommodating a power storage device element is formed so as to protrude from the heat-sealable resin layer side to the base material layer side of the exterior material for the power storage device, From the exterior material for the power storage device in which the recess is formed, an exterior material for a test target power storage device is extracted, and for the curved surface portion and the non-curved surface portion of the outer surface forming the recess of the exterior material for the test target power storage device, respectively, under the measurement conditions of the SCI method, a visual field of 10°, and a light source F2, the L * a * b * value in the color space of L * is measured, and based on the magnitude of the difference in the L * value, a determination step of determining whether the exterior material for the power storage device in which the recess is formed is a non-defective product, a step of accommodating a power storage device element in the recess of the exterior material for the power storage device to manufacture a power storage device, and is provided with When, as a result of the determination step, it is determined that the formed exterior material for the power storage device is a non-defective product, it is determined that the formation of the concave portion is appropriate, and a power storage device element is housed in the concave portion to manufacture a power storage device. A method for manufacturing a power storage device. Item 6. In the determination step, the L of the curved surface portion * value and the L of the non-curved surface portion * The method for manufacturing a power storage device according to item 5, wherein a product in which the absolute value of the difference from the value is 1.5 or less is determined to be a non-defective product. Item 7. The exterior material for the power storage device has a surface coating layer on the outside of the base material layer. The method for manufacturing a power storage device according to item 5 or 6. Item 8. The exterior material for the power storage device includes an adhesive layer between the base material layer and the barrier layer, The method for manufacturing a power storage device according to any one of items 5 to 7, wherein the adhesive layer is colored. Item 9. An inspection method for an exterior material for a power storage device in which a concave portion is formed, The inspection method is at least composed of an exterior material for a power storage device formed of a laminate including a base material layer, a barrier layer, and a heat-sealable resin layer in order from the outside, and the heat-sealable resin layer side protrudes from the heat-sealable resin layer side to the base material layer side. The exterior material for a power storage device in which a concave portion for housing a power storage device element is formed on the side is the inspection target, Regarding the curved surface portion and the non-curved surface portion of the outer surface forming the concave portion of the exterior material for the power storage device in which the concave portion is formed, respectively, under the measurement conditions of the SCI method, a visual field of 10°, and a light source F2, the L of the reflected light * a * b * In the color space, the L * value is measured, and based on the magnitude of the difference in the L * value, a determination step of determining whether or not the exterior material for the power storage device in which the concave portion is formed is a non-defective product is provided. An inspection method for an exterior material for a power storage device in which a concave portion is formed. Item 10. In the determination step, the L of the curved surface portion * value and the L of the non-curved surface portion *The inspection method according to item 9, wherein those with an absolute value of the difference from the value of 1.5 or less are determined to be non-defective products. Item 11. The inspection method according to item 9 or 10, wherein the exterior material for the power storage device includes a surface coating layer on the outside of the base material layer. Item 12. An exterior material for a power storage device composed of a laminate including at least, in order from the outside, a base material layer, a barrier layer, and a heat-sealable resin layer, the exterior material for the power storage device is formed so as to protrude from the heat-sealable resin layer side toward the base material layer side, and has a recess for accommodating a power storage device element on the heat-sealable resin layer side, Regarding the curved surface portion and the non-curved surface portion of the outer surface forming the recess of the exterior material for the power storage device, respectively, under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L * a * b * value in the color space * When measuring the value, the L * value of the curved surface portion and the L * value of the non-curved surface portion, the exterior material for the power storage device, wherein the absolute value of the difference therebetween is 1.5 or less. Item 13. The exterior material for the power storage device according to item 12, wherein the exterior material for the power storage device includes a surface coating layer on the outside of the base material layer. Item 14. The exterior material for the power storage device has an adhesive layer between the base material layer and the barrier layer, the adhesive layer is colored, the exterior material for the power storage device according to item 12 or 13. Item 15. An exterior material for a power storage device composed of a laminate including at least, in order from the outside, a base material layer, a barrier layer, and a heat-sealable resin layer, the exterior material for the power storage device is formed so as to protrude from the heat-sealable resin layer side toward the base material layer side under the following molding conditions to form a recess for accommodating a power storage device element on the heat-sealable resin layer side, and regarding the curved surface portion and the non-curved surface portion of the outer surface forming the recess of the exterior material for the power storage device, respectively, under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L * a * b * value in the color space* When measuring the value, the L of the curved surface portion * value and the L of the non-curved surface portion * The absolute value of the difference from is 1.5 or less, and the outer packaging material for a power storage device (Molding conditions) An outer packaging material for a power storage device is disposed between a molding die (female die) having a diameter of 54.5 mm (TD) × 31.6 mm (MD) and a corresponding molding die (male die) so that the female die side is the base material layer side, the pressing pressure (surface pressure) is 0.25 MPa, and cold molding is performed at a molding depth of 3.0 mm to form a rectangular recess in plan view. The clearance between the female die and the male die is 0.5 mm. The surface of the female die has a maximum height roughness (designated value of Rz) of 0.8 μm as defined in Table 2 of the reference surface roughness standard piece of JIS B 0659-1:2002, Annex 1. The corner R of the female die is 2.0 mm and the ridge line R is 2.5 mm. The surface of the male die has a maximum height roughness (designated value of Rz) of 3.2 μm as defined in Table 2 of the reference surface roughness standard piece of JIS B 0659-1:2002, Annex 1. The corner R of the male die is 2.0 mm and the ridge line R is 2.0 mm. The corner R and the ridge line R of the male die have a maximum height roughness (designated value of Rz) of 1.6 μm as defined in Table 2 of the reference surface roughness standard piece of JIS B 0659-1:2002, Annex 1 Item 16. The outer packaging material for a power storage device according to item 15, further comprising a surface coating layer outside the base material layer Item 17. The outer packaging material for a power storage device includes an adhesive layer between the base material layer and the barrier layer, The adhesive layer is colored, and the outer packaging material for a power storage device according to item 15 or 16 Item 18. A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the outer packaging material for a power storage device according to any one of items 12 to 14

Explanation of symbols

[0185] 1 Base material layer 2 Adhesive layer 3 Barrier layer 4 Heat-sealable resin layer 5 Successive layer 6 Surface coating layer 10 Exterior material for power storage device 11 Curved surface portion 11a Corner portion 11b Ridge line portion 12 Non-curved surface portion 13 Curved surface portion 14 Peripheral portion 100 Recessed portion

Claims

1. An exterior material for a power storage device, which is composed of a laminate including, in order from the outside, a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, wherein the surface coating layer is formed of a resin composition containing polyurethane, the surface coating layer contains an additive, the additive is at least one of an organic substance and an inorganic substance, the exterior material for a power storage device is molded so as to protrude from the heat-sealable resin layer side toward the base material layer side, and has a recess for accommodating a power storage device element on the heat-sealable resin layer side, The curved and non-curved portions of the outer surface forming the recess of the electrical storage device packaging material were measured using the SCI method, a field of view of 10°, and a light source F2, and the L of reflected light was measured. * a * b * L in color space * When the value is measured, the L * value and the L of the non-curved surface portion * and the absolute value of the difference is 1.5 or less.

2. An exterior material for a power storage device, which is composed of a laminate including, in order from the outside, a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, wherein the surface coating layer is formed of a resin composition containing polyurethane, the polyurethane is a polyurethane containing a main agent containing a polyol compound and a curing agent containing an aromatic isocyanate compound, the exterior material for a power storage device is molded so as to protrude from the heat-sealable resin layer side toward the base material layer side, and has a recess for accommodating a power storage device element on the heat-sealable resin layer side, For the curved surface part and the non-curved surface part of the outer surface forming the concave part of the exterior material for the power storage device, respectively, under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L of the reflected light * a * b * value in the color space, when measured, the L of the curved surface part * value, and the L of the non-curved surface part * value, the absolute value of the difference between them is 1.5 or less. An exterior material for a power storage device. * ​

3. An exterior material for a power storage device, which is composed of a laminate including, in order from the outside, a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, wherein the surface coating layer is formed of a resin composition containing polyurethane, the surface coating layer contains an additive, the additive is at least one of an organic substance and an inorganic substance, The exterior material for the power storage device is molded under the following molding conditions so as to protrude from the heat-fusible resin layer side toward the base material layer side, and a recess for accommodating a power storage device element is formed on the heat-fusible resin layer side. For the curved surface portion and the non-curved surface portion of the outer surface forming the recess of the exterior material for the power storage device, respectively, under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L * a * b * value in the color space is measured. When the absolute value of the difference between the L * value of the curved surface portion and the L * value of the non-curved surface portion is 1.5 or less, an exterior material for a power storage device. * ​ (Molding conditions) An exterior material for a power storage device is disposed between a molding die (female die) having a diameter of 54.5 mm (TD) × 31.6 mm (MD) and a corresponding molding die (male die) such that the female die side is the base material layer side. A pressing pressure (surface pressure) of 0.25 MPa is applied, and cold forming is performed at a forming depth of 3.0 mm to form a rectangular recess in plan view. The clearance between the female die and the male die is 0.5 mm. The surface of the female die has a maximum height roughness (designated value of Rz) of 0.8 μm as defined in Table 2 of the reference surface roughness standard piece in Annex 1 of JIS B 0659-1:2002. The corner R of the female die is 2.0 mm, and the ridge line R is 2.5 mm. The surface of the male die has a maximum height roughness (designated value of Rz) of 3.2 μm as defined in Table 2 of the reference surface roughness standard piece in Annex 1 of JIS B 0659-1:2002. The corner R of the male die is 2.0 mm, and the ridge line R is 2.0 mm. The corner R and the ridge line R of the male die have a maximum height roughness (designated value of Rz) of 1.6 μm as defined in Table 2 of the reference surface roughness standard piece in Annex 1 of JIS B 0659-1:2002.

4. An exterior material for a power storage device, which is composed of a laminate including, at least from the outside in order, a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer, wherein the surface coating layer is formed of a resin composition containing polyurethane, and the polyurethane is a polyurethane containing a main agent containing a polyol compound and a curing agent containing an aromatic isocyanate compound. The exterior material for the power storage device is molded under the following molding conditions so as to protrude from the heat-fusible resin layer side toward the base material layer side, and a recess for housing a power storage device element is formed on the heat-fusible resin layer side. For the curved surface portion and the non-curved surface portion of the outer surface forming the recess of the exterior material for the power storage device, respectively, under the measurement conditions of the SCI method, a visual field of 10°, and a light source F2, the L * a * b * value in the color space * is measured, and when the L * value of the curved surface portion and the L * of the non-curved surface portion satisfy that the absolute value of the difference therebetween is 1.5 or less, an exterior material for a power storage device. (Molding conditions) An exterior material for a power storage device is disposed between a molding die (female die) having a diameter of 54.5 mm (TD) × 31.6 mm (MD) and a corresponding molding die (male die) such that the female die side is the base material layer side. A pressing pressure (surface pressure) of 0.25 MPa is applied, and cold forming is performed at a forming depth of 3.0 mm to form a rectangular recess in plan view. The clearance between the female die and the male die is 0.5 mm. The surface of the female die has a maximum height roughness (designated value of Rz) of 0.8 μm as defined in Table 2 of the comparison surface roughness standard piece in Appendix 1 of JIS B 0659-1:2002 (reference). The corner R of the female die is 2.0 mm, and the ridge line R is 2.5 mm. The surface of the male die has a maximum height roughness (designated value of Rz) of 3.2 μm as defined in Table 2 of the comparison surface roughness standard piece in Appendix 1 of JIS B 0659-1:2002 (reference). The corner R of the male die is 2.0 mm, and the ridge line R is 2.0 mm. The corner R and the ridge line R of the male die have a maximum height roughness (designated value of Rz) of 1.6 μm as defined in Table 2 of the comparison surface roughness standard piece in Appendix 1 of JIS B 0659-1:2002 (reference).

5. The exterior material for a power storage device according to claim 1 or 3, wherein the additive contains titanium oxide.

6. The exterior material for a power storage device according to claim 2 or 4, wherein the aromatic isocyanate compound contains xylylene diisocyanate (XDI).

7. The exterior material for a power storage device according to any one of claims 1 to 6, wherein the surface coating layer is colored.

8. The exterior material for a power storage device includes an adhesive layer between the base material layer and the barrier layer, The exterior material for a power storage device according to any one of claims 1 to 7, wherein the adhesive layer is colored.

9. The exterior material for a power storage device according to any one of claims 1 to 8, wherein at least one of the surface and the interior of the base material layer has two or more types of lubricants.

10. The exterior material for a power storage device according to any one of claims 1 to 9, 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 in at least one of the surface and the interior of the base material layer.

11. The barrier layer contains at least one of an aluminum alloy foil and a stainless steel foil, and the exterior material for a power storage device according to any one of claims 1 to 10.

12. In the exterior material for a power storage device according to any one of claims 1 to 11, at least one of the surface and the interior of the heat-sealable resin layer contains two or more types of lubricants.

13. In the exterior material for a power storage device according to any one of claims 1 to 12, at least two types 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 in at least one of the surface and the interior of the heat-sealable resin layer.

14. The exterior material for a power storage device according to any one of claims 1 to 13 includes a colored layer between the base material layer and the barrier layer.

15. In the exterior material for a power storage device according to any one of claims 1 to 14, at least two types of lubricants are present in at least one of the surface and the interior of the surface coating layer.

16. In the exterior material for a power storage device according to any one of claims 1 to 15, at least one type 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 is present in at least one of the surface and the interior of the surface coating layer.

17. A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for a power storage device according to any one of claims 1 to 16.

18. It includes a step of obtaining an exterior material for a power storage device composed of a laminate in which at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer are laminated in this order, The surface coating layer is formed of a resin composition containing polyurethane, The exterior material for a power storage device is molded so as to protrude from the heat-sealable resin layer side toward the base material layer side, and has a recess for housing a power storage device element on the heat-sealable resin layer side, Regarding the curved surface part and the non-curved surface part of the outer surface forming the concave part of the exterior material for the power storage device, respectively, under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L of the reflected light * a * b * When measuring the L value in the color space, the L * value of the curved surface part and the L * value of the non-curved surface part * The absolute value of the difference between them is 1.5 or less, The surface coating layer contains an additive, The additive is at least one of an organic substance and an inorganic substance, and a method for manufacturing an exterior material for a power storage device.

19. A process for obtaining an exterior material for a power storage device, which is composed of a laminate in which at least a surface coating layer, a base material layer, a barrier layer, and a heat-sealable resin layer are laminated in this order, is provided. The surface coating layer is formed of a resin composition containing polyurethane. The exterior material for a power storage device is molded so as to protrude from the heat-sealable resin layer side toward the base material layer side, and has a recess for housing a power storage device element on the heat-sealable resin layer side. For the curved surface part and the non-curved surface part of the outer surface forming the concave part of the exterior material for the power storage device, respectively, under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L of the reflected light * a * b * value in the color space * When measured, the L of the curved surface part * value and the L of the non-curved surface part * The absolute value of the difference from is 1.5 or less, A method for manufacturing an exterior material for a power storage device, wherein the polyurethane is a polyurethane containing a main agent containing a polyol compound and a curing agent containing an aromatic isocyanate compound.

20. An adhesive layer is provided between the barrier layer and the heat-sealable resin layer. The adhesive layer and the heat-sealable resin layer are formed by a coextrusion lamination method, a tandem lamination method, a thermal lamination method, a sandwich lamination method, or a method of laminating an adhesive for forming the adhesive layer on the barrier layer and laminating the heat-sealable resin layer previously formed in a sheet shape on the adhesive layer. The method for manufacturing an exterior material for a power storage device according to claim 18 or 19.

21. The method for manufacturing an exterior material for a power storage device according to any one of claims 18 to 20, wherein the heat-sealable resin layer is formed of two or more layers of the same or different resins.

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