JP6424933B2 - Aluminum alloy foil for battery packaging material, battery packaging material, and battery - Google Patents

Description

  The present invention relates to an aluminum alloy foil for a battery packaging material, a battery packaging material, and a battery.

  Conventionally, various types of batteries have been developed. In these batteries, battery elements composed of electrodes, electrolytes and the like need to be sealed with a packaging material and the like. Metal packaging materials are widely used as battery packaging materials.

  In recent years, with the advancement of performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., batteries having various shapes are required. Moreover, thickness reduction, weight reduction, etc. are also calculated | required by the battery. However, it is difficult to follow the diversification of battery shapes with metal packaging materials that are frequently used conventionally. Moreover, since it is metal, there is a limit to weight reduction of the packaging material.

  Therefore, as a packaging material for a battery which can be easily processed into various shapes and which can realize thinning and weight reduction, for a film-shaped battery in which a base material layer / aluminum alloy foil / heat adhesive resin layer is sequentially laminated Packaging materials have been proposed.

  In such a film-like battery packaging material, generally, a concave portion is formed by cold forming, and a battery element such as an electrode or an electrolyte is disposed in a space formed by the concave portion, and heat fusion bonding is performed. By thermally fusing the resin layers, a battery is obtained in which the battery element is housed inside the battery packaging material.

  However, such a battery packaging material is thinner than a metal packaging material, and has a disadvantage that pinholes and cracks easily occur during molding.

  As an aluminum alloy foil whose formability is enhanced, for example, in Patent Document 1, Fe: 1.4% or more and 2.0% or less, Si: 0.15% or less in mass%, and the balance is Al An aluminum alloy soft foil is disclosed, which has a composition comprising: and unavoidable impurities, an average grain size of 5 .mu.m or less, and a maximum grain size / average grain size ratio of 3.5 or less. ing.

JP, 2015-203154, A

  The inventors of the present invention have found that when the formability is evaluated using an aluminum alloy foil having a small average crystal grain size as a packaging material for a battery, as in the conventional aluminum alloy foil as disclosed in Patent Document 1, It has been found that pinholes, cracks, etc. may occur in the aluminum alloy foil without being able to exhibit the high formability that has been achieved.

  The present invention is an invention made in view of such problems in the prior art. That is, the present invention provides an aluminum alloy foil which is less likely to cause pinholes or cracks by molding of a battery packaging material when used for a battery packaging material, and can exhibit excellent formability. As the main purpose. Furthermore, another object of the present invention is to provide a battery packaging material using the aluminum alloy foil, and a battery using the battery packaging material.

The present inventors diligently studied to solve the above-mentioned problems. As a result, crystal analysis by EBSD is performed on a cross section obtained by cutting the aluminum alloy foil in a direction perpendicular to the rolling direction of the aluminum alloy foil from the surface of the aluminum alloy foil. The ratio of the total area of {111} planes to the total area of crystal planes of the face-centered cubic lattice structure obtained is 10% or more, and the cross section is obtained by performing crystal analysis by EBSD method The aluminum alloy foil, in which the number average crystal grain size R (μm) of the crystal of the face-centered cubic lattice structure satisfies the following equation, is used as a packaging material for a battery, It has been found that pinholes and cracks do not easily occur during molding, and excellent moldability can be exhibited.
Number average crystal grain size R ≦ 0.056 × + 2.0
X = thickness of the aluminum alloy foil (μm)

  That is, the present inventors do not improve formability simply by reducing the average grain size of the aluminum alloy foil, and the direction perpendicular to the rolling direction of the aluminum alloy foil is a surface of the aluminum alloy foil. The cross section obtained by cutting the aluminum alloy foil in the vertical direction from the surface, the crystal plane of aluminum parallel to the cross section, obtained by performing crystal analysis by EBSD method, face-centered cubic lattice structure The ratio of the total area of {111} planes to the total area of crystal planes is 10% or more, and further, the number average crystal grain size of crystals of face-centered cubic lattice structure obtained from the cross section and the thickness of aluminum alloy foil It has been found that when it is used in a battery packaging material, it exhibits excellent formability, when it has a specific relationship.

  In the cross section, the {111} plane aligned in parallel to the cross section is synonymous with <111> // RD. Here, <111> // RD means that the <111> orientation of an aluminum alloy foil containing a face-centered cubic lattice (FCC) structure is parallel to the rolling direction (RD). .

  The present invention is an invention completed by repeating studies based on these findings.

That is, the present invention provides the inventions of the aspects listed below.
Item 1. An aluminum alloy foil for use in a battery packaging material,
Acquired by performing crystal analysis by EBSD on a cross section obtained by cutting the aluminum alloy foil in a direction perpendicular to the rolling direction of the aluminum alloy foil from the surface of the aluminum alloy foil. The ratio of the total area of {111} planes to the total area of crystal planes of face-centered cubic lattice structure is 10% or more, and
For battery packaging materials in which the number average crystal grain size R (μm) of crystals of face-centered cubic lattice structure obtained by performing crystal analysis by EBSD method for the cross section satisfies the following expression Aluminum alloy foil.
Number average crystal grain size R ≦ 0.056 × + 2.0
X = thickness of the aluminum alloy foil (μm)
Item 2. The aluminum alloy foil for a packaging material for a battery according to item 1, wherein the ratio (%) of the total area of {111} planes to the total area of crystal planes of the face-centered cubic lattice structure satisfies the following equation .
Ratio (%) of total area of {111} planes to total area of crystal planes of face-centered cubic lattice structure ≧ −1.1 × + 66
X = thickness of the aluminum alloy foil (μm)
Item 3. The aluminum alloy foil for a packaging material for a battery according to item 1 or 2, wherein the standard deviation St of the crystal grain size satisfies the following formula.
Standard deviation of crystal grain size St ≦ 0.09 × + 0.5
X = thickness of the aluminum alloy foil (μm)
Item 4. The aluminum alloy foil for battery packaging materials in any one of claim | item 1-3 which contains iron.
Item 5. 5. Any one of items 1 to 4, wherein the surface of the aluminum alloy foil is provided with an acid resistant film comprising at least one selected from the group consisting of phosphate, chromate, fluoride, and triazine thiol compound. Aluminum alloy foil for packaging materials for batteries as described in-.
Item 6. The aluminum alloy foil for a packaging material for a battery according to any one of Items 1 to 5, wherein an acid resistant film containing a cerium compound is provided on the surface of the aluminum alloy foil.
Item 7. An acid resistant coating is provided on the surface of the aluminum alloy foil,
7. The acid-resistant film according to any one of items 1 to 6, wherein a peak derived from at least one of Ce ⁺ and Cr ⁺ is detected when analyzed using time-of-flight secondary ion mass spectrometry. Aluminum alloy foil for battery packaging materials.
Item 8. 7. The packaging material for a battery according to any one of items 1 to 6, wherein the surface of the aluminum alloy foil is provided with an acid resistant film containing at least one element selected from the group consisting of phosphorus, chromium and cerium. Aluminum alloy foil.
Item 9. The packaging material for batteries comprised from the laminated body provided with a base material layer, the aluminum alloy foil for battery-cell packaging materials in any one of claim | item 1-8, and a heat fusible resin layer in this order.
Item 10. 10. A battery, wherein a battery element comprising at least a positive electrode, a negative electrode, and an electrolyte is contained in a package formed of the battery packaging material according to item 9.

  ADVANTAGE OF THE INVENTION According to this invention, it is hard to produce a pinhole and a crack at the time of shaping | molding of the packaging material for batteries by using for battery packaging materials, The aluminum alloy foil which can exhibit the outstanding formability can be provided. Further, according to the present invention, a battery packaging material using the aluminum alloy foil and a battery using the battery packaging material can also be provided.

It is a schematic diagram (a) of aluminum alloy foil which concerns on this invention, and a schematic diagram (b) of the packaging material for batteries. It is a photograph obtained by observing the shiny side of a commercially available aluminum alloy foil (Sun Foil manufactured by Toyo Aluminum Co., Ltd.) with a metallurgical microscope (magnification 100 times). The crystal plane of the face-centered cubic lattice structure in a cross section obtained by cutting the aluminum alloy foil in a direction perpendicular to the rolling direction of the aluminum alloy foil according to the present invention and perpendicular to the surface of the aluminum alloy foil. FIG. The colored area indicates the {111} plane. FIG. 1 is a schematic cross-sectional view of an example of a battery packaging material according to the present invention. FIG. 1 is a schematic cross-sectional view of an example of a battery packaging material according to the present invention. FIG. 1 is a schematic cross-sectional view of an example of a battery packaging material according to the present invention. FIG. 1 is a schematic cross-sectional view of an example of a battery packaging material according to the present invention. It is a graph which shows the relationship between the thickness X (μm) of the aluminum alloy foil in Examples and Comparative Examples and the ratio (%) of the total area of {111} planes to the total area of crystal planes of face-centered cubic lattice structure. . It is a graph which shows the relationship between thickness X (micrometer) of the aluminum alloy foil in an Example and a comparative example, and a number average grain size (micrometer). It is a graph which shows the relationship between thickness X (micrometer) of aluminum alloy foil in an Example and a comparative example, and the standard deviation of a crystal grain size. It is a graph which shows the relationship between thickness X (micrometer) of the aluminum alloy foil in an Example and a comparative example, and a limit forming depth (micrometer). It is a schematic diagram for demonstrating the method to perform the crystal analysis by EBSD method about the cross section of aluminum alloy foil.

The aluminum alloy foil of the present invention is used for a battery packaging material. In addition, the cross section obtained by cutting the aluminum alloy foil in a direction perpendicular to the rolling direction of the aluminum alloy foil from the surface of the aluminum alloy foil is obtained by performing crystal analysis by the EBSD method. Ratio of the total area of {111} planes to the total area of crystal planes of face-centered cubic lattice structure (hereinafter referred to as “total area of {111} planes to total area of crystal planes of face-centered cubic lattice structure” “Factor” may be abbreviated as “percentage of total area of {111} planes” is 10% or more, and face-centered cubic obtained by performing crystal analysis by EBSD method for the cross section The number average crystal grain size R (μm) of the crystal of the lattice structure is characterized by satisfying the following equation.
Number average crystal grain size R ≦ 0.056 × + 2.0
X = thickness of the aluminum alloy foil (μm)

  Hereinafter, the aluminum alloy foil of the present invention, a battery packaging material using the aluminum alloy foil, and a battery using the battery packaging material will be described in detail with reference to FIGS.

  In the present invention, the EBSD (Electron Back Scattered Diffraction Pattern: EBSD) method is an EBSD detector which is one of the detectors mounted on a scanning electron microscope (SEM). In this method, a Kikuchi pattern derived by electron beam backscattering diffraction is taken in by an EBSD detector screen and analyzed to measure a fine crystal orientation of a crystal sample. Further, in the present specification, with regard to the numerical range, the numerical range indicated by "-" means "above" or "below". For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. Aluminum alloy foil The aluminum alloy foil 1 of the present invention is used for a battery packaging material. Specifically, the aluminum alloy foil of the present invention is used for a film-like battery packaging material composed of a laminate, and in addition to the strength improvement of the battery packaging material, water vapor, oxygen, light, etc. inside the battery It functions as a barrier layer to prevent intrusion. Specific examples of the battery packaging material using the aluminum alloy foil of the present invention will be described later.

  In the present invention, the crystal analysis by EBSD is performed on a cross section obtained by cutting the aluminum alloy foil in a direction perpendicular to the rolling direction of the aluminum alloy foil from the surface of the aluminum alloy foil. The ratio of the total area of the {111} planes to the total area of the crystal planes of the face-centered cubic lattice structure obtained in the above is 10% or more. Here, the rolling direction of the aluminum alloy foil 1 corresponds to RD when the aluminum alloy foil is manufactured through the rolling process. In the rolling direction (RD) of the aluminum alloy foil 1, as shown in the schematic view of FIG. 1A, linear streaks called so-called rolling marks are formed on the surface of the aluminum alloy foil 1. Since the rolling marks extend along the rolling direction, the rolling direction of the aluminum alloy foil 1 can be grasped by observing the surface of the aluminum alloy foil 1. In the schematic diagram of FIG. 1, RD is an abbreviation for Rolling Direction, TD is a transverse direction, ND is a normal direction, and MD is an abbreviation for Machine Direction. For reference, in FIG. 1 (b), a battery packaging material 10 (as an example, one having a base layer 2 on one side of an aluminum alloy foil 1 and a heat fusible resin layer 3 on the other side) The schematic diagram of is also included. RD of the aluminum alloy foil 1 shown in FIG. 1 (a) corresponds to the MD of the battery packaging material 10 shown in FIG. 1 (b). Further, the TD of the aluminum alloy foil 1 shown in FIG. 1A corresponds to the TD of the battery packaging material 10 shown in FIG. 1B. Further, for reference, FIG. 2 shows a photograph obtained by observing a glossy surface of a commercially available aluminum alloy foil (Sun Foil manufactured by Toyo Aluminum Co., Ltd.) with a metallurgical microscope (magnification 100 ×). In the photograph of FIG. 2, it can be seen that the black linear streaks are rolling marks T and the rolling marks T extend in the rolling direction (RD). In addition, the rolling marks on the surface of the aluminum alloy foil can also be confirmed using an apparatus (such as an optical microscope) other than the metallographic microscope, as long as it is an apparatus capable of observing the surface by enlarging about 50 to 100 times.

  The aluminum alloy foil of the present invention contains an aluminum crystal having a face-centered cubic lattice structure, and in the present invention, paying attention to the {111} plane of the face-centered cubic lattice structure of the aluminum crystal, the crystal orientation of the aluminum crystal Is analyzed by the EBSD method. As described later, preferably, about 90% by mass or more of the aluminum alloy foil of the present invention is composed of aluminum, but depending on the composition of other components, aluminum crystals different from the face-centered cubic lattice structure are It may also be included.

  The fact that the aluminum alloy foil contains an aluminum crystal having a face-centered cubic lattice structure can be easily estimated from the Kikuchi pattern obtained by analyzing the aluminum alloy foil by the EBSD method. Furthermore, in order to accurately measure that the aluminum alloy foil contains an aluminum crystal having a face-centered cubic lattice structure, one of the following two methods is carried out. If the surface of the aluminum alloy foil is exposed, structural analysis can be performed using an X-ray diffractometer. In addition, if the aluminum alloy foil is covered with a resin or the like and the surface of the aluminum alloy foil is not exposed, first, the thickness of the aluminum alloy foil is polished, microtome, focused ion beam, broad ion beam or the like. Produces a section sample of about 100 nm or less. Next, for the sectioned sample, structural analysis can be performed by acquiring and analyzing a limited field diffraction pattern of a transmission electron microscope.

  FIG. 3 is a schematic view of a crystal plane of a face-centered cubic lattice structure in the cross section of the aluminum alloy foil according to the present invention. The colored area indicates the {111} plane.

  From the viewpoint of more effectively improving the formability of the aluminum alloy foil of the present invention, the ratio of the total area of the {111} plane is preferably about 20% or more, more preferably about 30% or more, and still more preferably About 40% or more, particularly preferably about 50% or more can be mentioned. In the aluminum alloy foil, since the {111} plane is a sliding surface during molding, when the ratio of the total area in the plane direction increases, crystals of the aluminum alloy slip easily, and the formability is enhanced. The ratio of the total area of the {111} planes means the total ratio of the areas of the {111} planes to the total area of the crystal planes of the face-centered cubic lattice structure arranged parallel to the above-mentioned cross section. doing. However, since an error may occur in the installation position when the measurement sample is installed on the sample table, an error of about 10 ° may be included in “parallel to the cross section”.

  The upper limit of the ratio of the total area of the {111} plane is not particularly limited, and may be about 100%, but there is a concern that the moldability may be reduced by specializing in spreadability in a specific direction. Preferably, it is about 90%, more preferably about 80%. In addition, the preferable range of the ratio of the total area of the {111} plane is about 20 to 90%, about 20 to 80%, about 30 to 90%, about 30 to 80%, about 40 to 90%, or 40 to 40%. About 80%, about 50 to 90%, about 50 to 80% can be mentioned.

Further, in the present invention, in order to more effectively improve the formability of the aluminum alloy foil, it is preferable that the ratio (%) of the total area of the {111} plane satisfies the following equation.
Percentage of total area of {111} planes (%) ≧ −1.1 × + 66
X = thickness of the aluminum alloy foil (μm)

  That is, when the thickness of the aluminum alloy foil is small, it is desirable that the proportion of the total area of the {111} planes is large. The smaller the thickness of the aluminum alloy foil, the more the proportion of the total area of the {111} planes is the formability Since the influence given to it becomes large, it becomes possible to exhibit still more excellent moldability by satisfying the above-mentioned formula.

Further, from the same viewpoint, the upper limit of the ratio of the total area of the {111} plane is not particularly limited, but it is preferable that, for example, the following formula is satisfied.
-Percentage of total area of 1.1X + 98 ≧ {111} face (%)
X = thickness of the aluminum alloy foil (μm)

Furthermore, in the present invention, a cross section obtained by cutting the aluminum alloy foil in a direction perpendicular to the rolling direction (RD) of the aluminum alloy foil and from the surface of the aluminum alloy foil in the vertical direction (ND) It is characterized in that the number average grain size R of the crystal of the face-centered cubic lattice structure obtained by conducting crystal analysis by the EBSD method satisfies the following equation.
Number average crystal grain size R ≦ 0.056 × + 2.0
X = thickness of the aluminum alloy foil (μm)

  The aluminum alloy foil of the present invention has the ratio of the total area of the {111} planes described above, and the number average grain size and the thickness of the aluminum alloy foil have such a specific relationship. Thus, they exhibit excellent formability. In the conventional aluminum alloy foil, the relationship between the thickness of the aluminum alloy foil and the number average crystal grain size is not taken into consideration. For example, when the thickness of the aluminum alloy foil is changed, there is a problem that the formability is reduced. On the other hand, in the aluminum alloy foil of the present invention, even when the thickness of the aluminum alloy foil is changed because the above-described number average crystal grain size and the thickness of the aluminum alloy foil have a specific relationship. It is possible to exhibit excellent formability, and in particular, even when the thickness of the aluminum alloy foil is thin as described later, excellent formability can be exhibited.

The lower limit of the number average crystal grain size R of the crystal of the face-centered cubic lattice structure is not particularly limited, and is preferably about 1 μm, and for example, it is preferable to satisfy the following formula. By satisfying the lower limit of about 1 μm or the following equation, the yield strength of the aluminum alloy foil does not become too high, and the aluminum alloy foil can be prevented from becoming hard and the formability being lowered.
0.056 × + 0.4 ≦ number average grain size R
X = thickness of the aluminum alloy foil (μm)

From the viewpoint of more effectively enhancing the formability of the aluminum alloy foil of the present invention, it is preferable that the standard deviation of the crystal grain size satisfies the following equation.
Standard deviation of crystal grain size St ≦ 0.09 × + 0.5
X = thickness of the aluminum alloy foil (μm)

  That is, since the standard deviation of the crystal grain size is small, the dispersion of the grain size of the crystal grains in the aluminum alloy foil is small, and it is deformed smoothly at the time of molding. And, as the thickness of the aluminum alloy foil becomes smaller, the influence of this standard deviation on the formability becomes larger, so by satisfying the above equation, it is possible to exhibit more excellent formability. .

  From the same viewpoint, the lower limit of the standard deviation of the crystal grain size is not particularly limited, and is preferably 0.

  In the present invention, the ratio of the total area of the {111} plane of the aluminum alloy foil, the number average crystal grain size, and the standard deviation of the crystal grain size are perpendicular to the rolling direction of the aluminum alloy foil, The cross section obtained by cutting the aluminum alloy foil in the vertical direction from the surface of the foil can be measured by performing crystal analysis by EBSD method. A schematic diagram for explaining a method of performing crystal analysis by EBSD method for a cross section of an aluminum alloy foil is shown in FIG. In FIG. 12, a sample of the aluminum alloy foil 1 is placed so that Axis 1 is ND, Axis 2 is TD, and Axis 3 is RD, and the electron beam from the objective lens 21 of the SEM is used for the cross section 1 a of the aluminum alloy foil 1. The line 21a is irradiated, and crystal analysis is performed from the Axis 3 direction by the EBSD detector 20. The angle formed by Axis 1, Axis 2 and Axis 3 is 90 °, and the sample of aluminum alloy foil 1 is inclined 70 ° in the Axis 1 direction. The specific measurement conditions are as follows.

The number average crystal grain size is the diameter when assuming the area calculated by [(measurement area-area of CI value 0.1 or less area) / number of crystals] to be a circle, and the crystal analysis by EBSD method It is a number average crystal grain size of the crystal included in the measurement area | region which several pieces of acquired images were connected and it was set to about 10000 micrometers ² or more.

In addition, the standard deviation of the crystal grain size is included in the measurement area of about 10000 μm ² or more by connecting a plurality of images acquired by crystal analysis by EBSD method after removing the area having a CI value of 0.1 or less. It is a value calculated from the distribution of crystal grain size (diameter when crystal area is assumed to be a circle) of crystals.

(measuring device)
An apparatus equipped with an EBSD detector (manufactured by TSL Solutions, Inc.) is used as a Schottky field emission scanning electron microscope.

(Preprocessing)
As pretreatment, the aluminum alloy foil is cut in the direction perpendicular to the rolling direction (RD) to obtain a cross section. The rolling direction of the aluminum alloy foil is a direction in which a linear rolling mark extends when the shiny surface of the aluminum alloy foil is observed with a metallographic microscope. As a specific procedure, first, an aluminum alloy foil as a sample is cut out to 5 mm (direction perpendicular to the rolling direction) × 10 mm (rolling direction) with a trimming razor, and then embedded in a resin. Next, using a trimming razor, the aluminum alloy foil is cut together with the resin in a direction perpendicular to the rolling direction of the aluminum alloy foil and perpendicularly from the surface of the aluminum alloy foil to expose the cross section of the aluminum alloy foil Let The resulting cross-section is then trimmed using a microtome. In this trimming, in order to reduce the mechanical strain of the cut surface, the embedded resin is cut with a microtome by about 1 mm in the direction perpendicular to the cross section. Next, using a ion milling apparatus, a broad argon beam is irradiated in the direction perpendicular to the cross section to produce a measurement cross section. This is an operation of precisely exposing the cross section of the aluminum alloy foil so as to minimize the breakdown to the mechanical crystal structure occurring in the previous step. In the present invention, “perpendicular direction” at the time of cutting the aluminum alloy foil may include an error of about 10 ° because it is confirmed and performed under a stereomicroscope. That is, the direction perpendicular to the rolling direction is 80 to 100 ° in the rolling direction, and the direction perpendicular to the surface is 80 to 100 ° with respect to the surface.

(SEM conditions)
The conditions of the scanning electron microscope (SEM) used for the EBSD method are as follows.
Observation magnification: 2000 times acceleration voltage: 15kV
Working distance: 15 mm
Inclination angle: 70 °

(EBSD condition)
The conditions for crystal analysis by EBSD method are as follows.
Step size: 200 nm
Analysis condition:
Perform the following analysis using crystal orientation analysis software OIM (Ver 7.3) manufactured by TSL Solutions, Inc.
A plurality of images are connected, and the measurement area is about 10000 μm ² or more. At this time, from the center in the thickness direction of the aluminum alloy foil to both ends is taken as a measurement region, and the portion where the resin is attached to the cross section and the portion where the acid resistant film is present are excluded from the measurement region.
After connecting the images, check the pole figure.
If the pole figure centers are shifted by 10 ° or more, the crystal data is rotated to achieve symmetry. In addition, the pole figure used as the reference in that case is measured from the sample surface by XRD. In addition, when pole figure is obtained from the surface by EBSD, in order to remove the influence of the mechanical crystal structure of the sample surface, after performing mechanical polishing, planar milling, electric field polishing, etc. of the sample surface, a wide range measurement is performed. Thereafter, the pole figure obtained from the surface direction is rotated by 90 ° so as to be the same as that obtained from the same orientation as the pole figure obtained from the cross section of the target sample. Refer to this pole figure.
Analysis is performed excluding the data whose reliability index (Confidence Index: CI value) CI value is 0.1 or less, which is defined by crystal orientation analysis software OIM (Ver. 7.3) manufactured by TSL Solutions, Inc. As a result, it is possible to exclude data based on the resin used for the pretreatment existing on the front and back of the sample, the grain boundary existing in the cross section, and the amorphous state.
When calculating the percentage of the total area of {111} planes, analysis is performed at an allowable angle of 15 °.

  In the battery using the battery packaging material of the present invention, the ratio of the total area of the {111} plane of the aluminum alloy foil, the number average crystal grain size, and the standard deviation of the crystal grain size are measured The battery packaging material can be cut out from the flat part of the battery to perform these measurements.

  The thickness of the aluminum alloy foil of the present invention is not particularly limited, but preferably about 10 to 100 μm from the viewpoint of suitably using the battery packaging material. As described above, the aluminum alloy foil of the present invention has the proportion of the total area of the {111} planes described above, and the above-mentioned specific relationship between the number average crystal grain size and the thickness of the aluminum alloy foil By having it, it exhibits excellent formability. Therefore, even if the thickness of the aluminum alloy foil of the present invention is, for example, about 100 μm or less, or about 80 μm or less, or even about 40 μm or less, excellent formability can be exhibited. The thickness of the aluminum alloy foil of the present invention is preferably about 10 μm or more, more preferably about 15 μm or more, and preferably about 20 μm from the viewpoint of suitably using the battery packaging material to be provided for molding. It is more preferable that it is more than. Furthermore, the thickness range of the aluminum alloy foil is preferably about 10 to 80 μm, about 15 to 100 μm, about 15 to 80 μm, about 15 to 40 μm, about 20 to 100 μm, about 20 to 80 μm, or about 20 to 40 μm. It can be mentioned. Since the aluminum alloy foil of the present invention exhibits excellent formability, for example, even when the thickness of the aluminum alloy foil is as thin as about 10 to 40 μm, or even about 10 to 20 μm, it is suitable as a battery packaging material. It can be used.

  The aluminum alloy foil of the present invention preferably contains iron from the viewpoint of enhancing the formability. The content of iron is preferably about 0.5 to 2.0% by mass, and more preferably about 1.2 to 1.8% by mass. The composition of the aluminum alloy constituting the aluminum alloy foil layer can be identified by elemental analysis. In addition, the composition of the aluminum alloy can be quantified by ICP (Inductively Coupled Plasma Atomic Emission Spectroscopy: ICP-AES).

  The aluminum alloy constituting the aluminum alloy foil is not particularly limited, but from the viewpoint of exhibiting excellent formability, the content of aluminum contained in the aluminum alloy is preferably 90% by mass or more. Specific examples of the aluminum alloy preferably have a composition defined in JIS H 4160: 1994 A802 1 H-O, JIS H 4 160: 1994 A 8079 H-O, JIS H 4000: 2014 A 802 1 P-O, JIS H 4000: 2014 A 8079 P-O, etc. A soft aluminum alloy is mentioned.

  The aluminum alloy foil having the above features can be manufactured by a known manufacturing method, and can be manufactured, for example, by appropriately adjusting the composition, rolling conditions, thickness and the like of the aluminum alloy. The composition of the aluminum alloy includes, for example, the presence or absence of a combination of metals other than aluminum contained in the aluminum alloy (for example, at least one of iron, copper, nickel, silicon, manganese, magnesium, chromium, zinc, titanium, etc.) Adjust the amount. As a composition of an aluminum alloy, the composition mentioned above is preferable.

  Moreover, as rolling conditions, conditions, such as a rolling ratio, heating temperature, heating time, are adjusted. For example, a step of homogenizing the aluminum metal or aluminum alloy ingot at about 500 to 600 ° C. for about 1 to 2 hours, a step of hot rolling, a step of cold rolling, about 1 to 10 hours at about 300 to 450 ° C. A process of holding intermediate annealing, a cold rolling process in which a rolling reduction from intermediate annealing to final rolling is 80% or more, more preferably 90% or more, final holding at about 250 to 400 ° C. for about 30 to 100 hours There is a method including an annealing step.

  Further, it is preferable that at least one surface, preferably both surfaces, of the aluminum alloy foil 1 be subjected to chemical conversion treatment in order to stabilize adhesion, to prevent dissolution and corrosion, and the like. Here, the chemical conversion treatment means a treatment for forming an acid resistant film on the surface of an aluminum alloy foil. As the chemical conversion treatment, for example, chromate treatment using a chromium compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium borate, chromium biphosphate, chromium acetate, acetyl acetate, chromium chloride, potassium chromium sulfate, etc .; Phosphoric acid treatment using phosphoric acid compounds such as sodium acid, potassium phosphate, ammonium phosphate, polyphosphoric acid and the like; using an aminated phenol polymer having repeating units represented by the following general formulas (1) to (4) And chemical conversion treatment. Among the chromium compounds, chromic acid compounds are preferred. In the aminated phenol polymer, repeating units represented by the following general formulas (1) to (4) may be contained singly or in any combination of two or more. It is also good.

In general formulas (1) to (4), X represents a hydrogen atom, a hydroxyl group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. Also, R ¹ and R ² are the same or different and each independently represent a hydroxyl group, an alkyl group or a hydroxyalkyl group. In the general formulas (1) to (4), examples of the alkyl group represented by X, R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group and an isobutyl group, C1-C4 linear or branched alkyl groups, such as a tert- butyl group, are mentioned. Also, examples of the hydroxyalkyl group represented by X, R ¹ and R ² include, for example, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3- C1-C4 linear or branched with one hydroxy group such as hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group etc. An alkyl group is mentioned. In the general formulas (1) to (4), the alkyl group and the hydroxyalkyl group represented by X, R ¹ and R ² may be identical to or different from each other. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxyl group or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having repeating units represented by the general formulas (1) to (4) is, for example, preferably about 500 to 1,000,000, and about 1 to 20,000. More preferable.

  In addition, as a chemical conversion treatment method for imparting corrosion resistance to aluminum alloy foil 1, a coating in which fine particles of aluminum oxide, titanium oxide, cerium oxide, metal oxide such as tin oxide, or barium sulfate are dispersed in phosphoric acid is coated A method of forming a corrosion resistant treatment layer on the surface of the aluminum alloy foil 1 by baking at about 150 ° C. or higher may be mentioned. In addition, a resin layer obtained by crosslinking the cationic polymer with a crosslinking agent may be further formed on the corrosion-resistant layer. Here, as the cationic polymer, for example, polyethylene imine, an ionic polymer complex composed of polyethylene imine and a polymer having a carboxylic acid, primary amine graft acrylic resin obtained by graft polymerizing a primary amine on an acrylic main skeleton, polyallylamine Or derivatives thereof, aminophenol and the like. As these cationic polymers, only 1 type may be used and you may use combining 2 or more types. Moreover, as a crosslinking agent, the compound which has an at least 1 sort (s) of functional group chosen from the group which consists of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, a silane coupling agent etc. are mentioned, for example. As these crosslinking agents, only one type may be used, or two or more types may be used in combination.

  Moreover, as a method of specifically providing an acid resistant coating, for example, at least the surface on the inner layer side of an aluminum alloy foil is first subjected to an alkaline dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method. Degreasing treatment by a known treatment method such as acid activation method, and then the degreasing surface is treated with metal phosphate such as chromium phosphate, titanium phosphate, zirconium phosphate, zinc phosphate and the like Treatment solution (aqueous solution) mainly composed of a mixture of metal salts, or treatment solution (aqueous solution) mainly composed of a mixture of nonmetal phosphate and nonmetal salts thereof, or acrylic resin with these Or by applying a treatment solution (aqueous solution) composed of a mixture with a phenol-based resin or a water-based synthetic resin such as a urethane-based resin by a known coating method such as roll coating, gravure printing, or dipping. , It is possible to form the acid-resistant coating. For example, when treated with a chromium phosphate salt-based treatment solution, it becomes an acid resistant film composed of chromium phosphate, aluminum phosphate, aluminum oxide, aluminum hydroxide, aluminum fluoride, etc., and is treated with a zinc phosphate salt treatment solution In the case of an acid resistant coating, the coating is made of zinc phosphate hydrate, aluminum phosphate, aluminum oxide, aluminum hydroxide, aluminum fluoride and the like.

  Moreover, as another example of the specific method of providing an acid resistant film, for example, at least the surface on the inner layer side of an aluminum alloy foil is first subjected to an alkaline dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid An acid resistant film can be formed by degreasing treatment by a known treatment method such as activation method and then applying known anodic oxidation treatment to the degreasing treatment surface.

  Moreover, phosphate-based and chromic acid-based films are mentioned as another example of the acid resistant film. Examples of phosphates include zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate and chromium phosphate. Examples of chromic acid include chromium chromate.

  Moreover, as another example of the acid resistant coating, by forming an acid resistant coating such as phosphate, chromate, fluoride, triazine thiol compound, etc., between the aluminum and the substrate layer at the time of embossing and forming Anti-delamination, hydrogen fluoride generated by the reaction between electrolyte and water prevents dissolution and corrosion of the aluminum surface, especially dissolution and corrosion of aluminum oxide present on the aluminum surface, and adhesion of the aluminum surface The properties (wettability) are improved, and the effect of preventing the delamination of the base layer and aluminum during heat sealing and the prevention of the delamination of the base layer and aluminum during press molding are shown in the embossed type. Among the substances forming the acid resistant film, an aqueous solution composed of three components of a phenol resin, a chromium (III) fluoride compound, and phosphoric acid is applied to the aluminum surface, and the treatment of dry baking is good.

  The acid resistant film further comprises a layer having cerium oxide, phosphoric acid or phosphate, an anionic polymer, and a crosslinking agent for crosslinking the anionic polymer, wherein the phosphoric acid or phosphate is any of the above-mentioned. About 1 to 100 parts by mass may be blended with 100 parts by mass of cerium oxide. It is preferable that the acid resistant film has a multilayer structure further including a layer having a cationic polymer and a crosslinking agent for crosslinking the cationic polymer.

  Furthermore, it is preferable that the said anionic polymer is a copolymer which has poly (meth) acrylic acid or its salt, or (meth) acrylic acid or its salt as a main component. Moreover, it is preferable that the said crosslinking agent is at least 1 sort (s) chosen from the group which consists of a compound which has a functional group in any one of an isocyanate group, glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent.

  Moreover, it is preferable that the said phosphoric acid or phosphate is condensed phosphoric acid or condensed phosphate.

  For the chemical conversion treatment, only one type of chemical conversion treatment may be performed, or two or more types of chemical conversion treatments may be performed in combination. Furthermore, these chemical conversion treatments may be performed using one type of compound alone, or may be performed using two or more types of compounds in combination. Among the chemical conversion treatments, a chromate treatment, a chemical conversion treatment in which a chromium compound, a phosphoric acid compound, and an aminated phenol polymer are combined, and the like are preferable.

  Specific examples of the acid resistant coating include those containing at least one of phosphate, chromate, fluoride, and triazine thiol. In addition, an acid resistant film containing a cerium compound is also preferable. As a cerium compound, cerium oxide is preferable.

  Moreover, as a specific example of an acid resistant film, a phosphate type film, a chromate type film, a fluoride type film, a triazine thiol compound film, etc. are mentioned. The acid resistant coating may be one of these or a combination of two or more. Furthermore, as an acid resistant coating, after degreasing the surface of the aluminum alloy foil on the chemical conversion treatment, a treatment liquid comprising a mixture of a metal phosphate and an aqueous synthetic resin, or a mixture of a nonmetallic phosphate and an aqueous synthetic resin It may be formed of a treatment liquid comprising

The analysis of the composition of the acid-resistant film can be performed using, for example, time-of-flight secondary ion mass spectrometry. Analysis of the composition of the acid-resistant film using time-of-flight secondary ion mass spectrometry detects, for example, a peak derived from at least one of Ce ⁺ and Cr ⁺ .

  It is preferable that the surface of the aluminum alloy foil is provided with an acid resistant film containing at least one element selected from the group consisting of phosphorus, chromium and cerium. In addition, it is confirmed using X-ray photoelectron spectroscopy that at least one element selected from the group consisting of phosphorus, chromium and cerium is contained in the acid resistant coating on the surface of the aluminum alloy foil of the packaging material for batteries. can do. Specifically, first, in the battery packaging material, the heat fusible resin layer, the adhesive layer and the like laminated on the aluminum alloy foil are physically peeled off. Next, the aluminum alloy foil is placed in an electric furnace and left at about 300 ° C. for about 30 minutes to remove the organic components present on the surface of the aluminum alloy foil. Thereafter, X-ray photoelectron spectroscopy of the surface of the aluminum alloy foil is used to confirm that these elements are contained.

The amount of acid-resistant coatings to be formed on the surface of the aluminum alloy foil 1 in the chemical conversion treatment is not particularly limited, for example, in the case of performing the above-mentioned chromate treatment, the surface 1 m ² per aluminum alloy foil 1, the chromium compound Is about 0.5 to 50 mg, preferably about 1.0 to 40 mg, in terms of chromium, about 0.5 to 50 mg, preferably about 1.0 to 40 mg, of the phosphorus compound in terms of phosphorus, and 1 of the aminated phenolic polymer is It is desirable that the content is about 0 to 200 mg, preferably about 5.0 to 150 mg.

  The thickness of the acid-resistant coating is not particularly limited, but is preferably about 1 nm to 10 μm, more preferably 1 to 100 nm, from the viewpoint of the cohesion of the coating and the adhesion to the aluminum alloy foil and the heat sealable resin layer. The degree is more preferably about 1 to 50 nm. The thickness of the acid resistant coating can be measured by a transmission electron microscope or a combination of an observation by a transmission electron microscope and energy dispersive X-ray spectroscopy or electron beam energy loss spectroscopy.

  The chemical conversion treatment is performed by applying a solution containing a compound used to form an acid-resistant film to the surface of an aluminum alloy foil by a bar coating method, a roll coating method, a gravure coating method, an immersion method, etc. Is carried out by heating to about 70 to 200.degree. In addition, before the aluminum alloy foil is subjected to the chemical conversion treatment, the aluminum alloy foil may be previously subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method or the like. By performing the degreasing treatment in this manner, the chemical conversion treatment of the surface of the aluminum alloy foil can be performed more efficiently.

  As described later, the aluminum alloy foil of the present invention can be suitably used for the battery packaging material of the present invention. That is, the aluminum alloy foil of the present invention is an aluminum alloy foil in a battery packaging material composed of a laminate including at least a base material layer, an aluminum alloy foil, and a heat fusible resin layer in this order, It can be used suitably.

2. Battery packaging material
Laminated Structure As shown in FIG. 4, the battery packaging material of the present invention is composed of a laminate having at least a base material layer 2, an aluminum alloy foil 1, and a thermally fusible resin layer 3 in this order. In the battery packaging material of the present invention, the base material layer 2 is on the outermost layer side, and the thermally fusible resin layer 3 is an innermost layer. That is, at the time of assembly of the battery, the battery element is sealed by sealing the battery element by thermally fusing the heat-fusible resin layers 3 located on the peripheral edge of the battery element.

  The battery packaging material of the present invention, as shown in FIG. 5, is provided with an adhesive layer 4 between the base layer 2 and the aluminum alloy foil 1 as necessary for the purpose of enhancing the adhesiveness thereof. May be In addition, as shown in FIG. 6, an adhesive layer 5 may be provided between the aluminum alloy foil 1 and the heat-fusible resin layer 3 as necessary for the purpose of enhancing the adhesiveness thereof. Moreover, as shown in FIG. 7, the surface coating layer 6 etc. may be provided in the outer side (the opposite side to the heat-fusible resin layer 3) of the base material layer 2 as needed.

  The thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited, but it is preferably about 160 μm or less, from the viewpoint of exhibiting high formability while making the thickness of the laminate as thin as possible. More preferably, it is about 35-155 micrometers, More preferably, it is about 45-120 micrometers. According to the present invention, excellent formability can be exhibited even when the thickness of the laminate constituting the battery packaging material of the present invention is as thin as, for example, about 160 μm or less. Therefore, the battery packaging material of the present invention can contribute to the improvement of the energy density of the battery.

Each Layer Forming a Packaging Material for a Battery [Base Layer 2]
In the battery packaging material of the present invention, the base material layer 2 is a layer located on the outermost layer side. The material for forming the base layer 2 is not particularly limited as long as it has insulating properties. Examples of materials for forming the base material layer 2 include resin films such as polyester resin, polyamide resin, epoxy resin, acrylic resin, fluorine resin, polyurethane resin, silicone resin, phenol resin, and mixtures or copolymers thereof. It can be mentioned. Among these, a polyester resin and a polyamide resin are preferably mentioned, and a biaxially stretched polyester resin and a biaxially stretched polyamide resin are more preferably mentioned. Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolyester, and polycarbonate. Specific examples of the polyamide resin include nylon 6, nylon 66, a copolymer of nylon 6 and nylon 66, nylon 6, 10, polymethaxylylene adipamide (MXD6) and the like.

  The base material layer 2 may be formed of a resin film of one layer, but may be formed of a resin film of two or more layers in order to improve pinhole resistance and insulation. Specifically, a multilayer structure in which a polyester film and a nylon film are laminated, a multilayer structure in which a plurality of nylon films are laminated, and a multilayer structure in which a plurality of polyester films are laminated are exemplified. When the substrate layer 2 has a multilayer structure, a laminate of a biaxially stretched nylon film and a biaxially stretched polyester film, a laminate of a plurality of biaxially stretched nylon films laminated, and a laminate of a plurality of biaxially stretched polyester films laminated Body is preferred. For example, when forming the base material layer 2 from a resin film of two layers, it is made the composition which laminates polyester resin and polyester resin, the composition which laminates polyamide resin and polyamide resin, or the composition which laminates polyester resin and polyamide resin. It is more preferable to use a structure in which polyethylene terephthalate and polyethylene terephthalate are laminated, a structure in which nylon and nylon are laminated, or a structure in which polyethylene terephthalate and nylon are laminated. In addition, since the polyester resin is difficult to be discolored, for example, when the electrolytic solution adheres to the surface, it is preferable to laminate the base material layer 2 so that the polyester resin is positioned at the outermost layer in the laminated structure. In the case where the base material layer 2 has a multilayer structure, the thickness of each layer is preferably about 2 to 25 μm.

  When the base material layer 2 is formed of a multilayer resin film, two or more resin films may be laminated via an adhesive or an adhesive component such as adhesive resin, and the type and amount of adhesive component used, etc. The same applies to the case of the adhesive layer 4 described later. In addition, it does not restrict | limit especially as a method to laminate the resin film of two or more layers, A well-known method can be adopted, for example, a dry laminating method, a sandwich laminating method, etc. are mentioned, Preferably a dry laminating method is mentioned. When laminating by the dry lamination method, it is preferable to use a urethane type adhesive as an adhesive layer. At this time, the thickness of the adhesive layer is, for example, about 2 to 5 μm.

  In the present invention, from the viewpoint of enhancing the formability of the battery packaging material, it is preferable that a lubricant is present on the surface of the base layer 2. The lubricant is not particularly limited, but preferably includes amide lubricants. Specific examples of the amide lubricant include saturated fatty acid amide, unsaturated fatty acid amide, substituted amide, methylolamide, saturated fatty acid bisamide, unsaturated fatty acid bisamide and the like. Specific examples of the saturated fatty acid amide 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 amide include oleic acid amide and erucic acid amide. Specific examples of the substituted amide include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. In addition, specific examples of methylolamide include methylol stearic acid amide and the like. Specific examples of the saturated fatty acid bisamide include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylene bisstearin An acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N, N'-distearyl adipic acid amide, N, N'-distearyl sebacic acid amide etc. are mentioned. Specific examples of the unsaturated fatty acid bisamide include ethylene bis oleic acid amide, ethylene bis erucic acid amide, hexamethylene bis oleic acid amide, N, N'-dioleyl adipic acid amide, N, N'-dioleyl sebacic acid amide Etc. Specific examples of fatty acid ester amides include stearoamidoethyl stearate and the like. Moreover, m-xylylene bis-stearic acid amide, m-xylylene bis-hydroxystearic acid amide, N, N'-distearyl isophthalic acid amide etc. are mentioned as a specific example of aromatic-type bisamide. The lubricant may be used alone or in combination of two or more.

When a lubricant is present on the surface of the base layer 2, the amount thereof is not particularly limited, but it is preferably about 3 mg / m ² or more, more preferably 4 to 15 mg / in an environment of 24 ° C. and 60% relative humidity. m ² approximately, more preferably include about 5~14mg / m ^2.

  The base layer 2 may contain a lubricant. The lubricant present on the surface of the substrate layer 2 may be one in which the lubricant contained in the resin constituting the substrate layer 2 is exuded, or the lubricant applied to the surface of the substrate layer 2 It may be

  The dynamic friction coefficient of the surface of the base material 2 side of the battery packaging material of the present invention is preferably about 0.5 or less, more preferably about 0.3 or less, and even more preferably about 0, from the viewpoint of enhancing the formability. .2 or less is mentioned. The lower limit of the dynamic friction coefficient is about 0.01. Moreover, as a preferable range of the said dynamic friction coefficient, about 0.01-0.5, about 0.01-0.3, about 0.01-0.2 is mentioned. In addition, the said dynamic friction coefficient is the value measured based on the method prescribed | regulated to JISK7125: 1999.

  The thickness of the base material layer 2 is not particularly limited as long as it exhibits the function as a base material layer, and for example, about 3 to 50 μm, preferably about 10 to 35 μm.

[Adhesive layer 4]
In the battery packaging material of the present invention, the adhesive layer 4 is a layer provided between the base layer 2 and the aluminum alloy foil 1 as needed in order to firmly bond the base layer 2 and the aluminum alloy foil 1.

  The adhesive layer 4 is formed of an adhesive that can bond the base layer 2 and the aluminum alloy foil 1. The adhesive used to form the adhesive layer 4 may be a two-part curable adhesive or a one-part curable adhesive. Furthermore, the adhesion mechanism of the adhesive used to form the adhesive layer 4 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a heat pressure type, and the like.

  Specific examples of the adhesive component that can be used to form the adhesive layer 4 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolyesters; Polyether-based adhesives; Polyurethane-based adhesives; Epoxy-based resins; Phenolic resin-based resins; Polyamide-based resins such as nylon 6, nylon 66, nylon 12, copolymerized polyamides; Polyolefins, carboxylic acid-modified polyolefins, metal-modified polyolefins, etc. Polyolefin resins, polyvinyl acetate resins; cellulose adhesives; (meth) acrylic resins; polyimide resins; amino resins such as urea resins and melamine resins; chloroprene rubber, nitrile rubber , Styrene - rubber such as 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.

  The thickness of the adhesive layer 4 is not particularly limited as long as it exhibits a function as an adhesive layer, and for example, about 1 to 10 μm, preferably about 2 to 5 μm.

[Aluminum alloy foil 1]
In the battery packaging material, the aluminum alloy foil 1 is a layer having a function to prevent water vapor, oxygen, light and the like from invading the inside of the battery, in addition to the strength improvement of the battery packaging material. In the present invention, as the aluminum alloy foil 1, the above-mentioned aluminum alloy foil 1 of the present invention can be used. The details of the aluminum alloy foil 1 of the present invention are as described above.

  In the battery packaging material of the present invention, since the above-described aluminum alloy foil of the present invention is used, it has excellent formability. The thickness X of the aluminum alloy foil 1 can be measured by observing the cross section of the battery packaging material even in a state of being laminated in the battery packaging material. Further, the crystal analysis by EBSD method for the cross section obtained by cutting the aluminum alloy foil in a direction perpendicular to the rolling direction of the aluminum alloy foil and perpendicular to the surface of the aluminum alloy foil is also a battery packaging material. It can be carried out in a state in which an aluminum alloy foil is laminated on the The specific measurement conditions are as described above (pretreatment), in which the battery packaging material is embedded in a resin, and it is perpendicular to the rolling direction (RD) of the aluminum alloy foil and perpendicular to the surface of the aluminum alloy foil. Except for cutting the battery packaging material in the direction (ND) to obtain a cross section of the aluminum alloy foil, the analysis conditions are the same as those of the aluminum alloy foil 1 described above.

[Adhesive layer 5]
In the battery packaging material of the present invention, the adhesive layer 5 is a layer provided between the aluminum alloy foil 1 and the heat-fusible resin layer 3 as needed in order to firmly bond the heat-fusible resin layer 3.

  The adhesive layer 5 is formed of a resin capable of adhering the aluminum alloy foil 1 and the heat fusible resin layer 3. As the resin used to form the adhesive layer 5, the adhesive mechanism, the type of the adhesive component, etc. may be the same as the adhesive exemplified for the adhesive layer 4. Moreover, as resin used for formation of the contact bonding layer 5, polyolefin resin, such as polyolefin illustrated by the below-mentioned heat-fusion resin layer 3, cyclic polyolefin, carboxylic acid modified polyolefin, carboxylic acid modified cyclic polyolefin, can also be used . As the polyolefin, a carboxylic acid-modified polyolefin is preferable, and a carboxylic acid-modified polypropylene is particularly preferable, from the viewpoint of excellent adhesion between the aluminum alloy foil 1 and the heat-fusible resin layer 3. That is, the adhesive layer 5 may contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The adhesive layer 5 may contain a polyolefin skeleton, for example, by infrared spectroscopy, gas chromatography mass spectrometry, etc., and the analysis method is not particularly limited. For example, when a maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected in the vicinity of wave number 1760 cm −1 and wave number 1780 cm −1.

  Furthermore, from the viewpoint of providing a battery packaging material having good adhesiveness while reducing the thickness of the battery packaging material, the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. May be As the acid-modified polyolefin, preferably, the same as the carboxylic acid-modified polyolefin and the carboxylic acid-modified cyclic polyolefin exemplified in the heat fusible resin layer 3 can be exemplified.

  The curing agent is not particularly limited as long as it cures acid-modified polyolefin. Examples of the curing agent include epoxy-based curing agents, polyfunctional isocyanate-based curing agents, carbodiimide-based curing agents, oxazoline-based curing agents, and the like.

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

  The polyfunctional isocyanate-based curing agent is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), those obtained by polymerizing or denating these, or the like Mixtures and copolymers with other polymers may be mentioned.

  The carbodiimide curing agent is not particularly limited as long as it is a compound having at least one carbodiimide group (-N = C = N-). As a carbodiimide type | system | group hardening | curing agent, the polycarbodiimide compound which has a carbodiimide group 2 or more at least is preferable.

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

  From the viewpoint of enhancing the adhesion between the aluminum alloy foil 1 and the thermally fusible resin layer 3 by the adhesive layer 5, the curing agent may be composed of two or more types of compounds.

  The content of the curing agent in the resin composition forming the adhesive layer 5 is preferably in the range of about 0.1 to 50% by mass, and more preferably in the range of about 0.1 to 30% by mass, More preferably, it is in the range of about 0.1 to 10% by mass.

  The thickness of the adhesive layer 5 is not particularly limited as long as it exhibits the function as an adhesive layer, but if the adhesive exemplified in the adhesive layer 4 is used, it is preferably about 2 to 10 μm, more preferably 2 to 2 There is about 5 μm. Further, in the case of using the resin exemplified for the heat fusible resin layer 3, it is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. In the case of a cured product of an acid-modified polyolefin and a curing agent, it is preferably about 30 μm or less, more preferably about 0.1 to 20 μm, and still more preferably about 0.5 to 5 μm. When the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed by applying the resin composition and curing it by heating or the like.

[Heat-fusible resin layer 3]
In the battery packaging material of the present invention, the heat fusible resin layer 3 corresponds to the innermost layer, and is a layer which thermally welds the heat fusible resin layers when the battery is assembled to seal the battery element.

  The resin component used for the heat-fusible resin layer 3 of the present invention is not particularly limited as long as it can be heat-welded, and examples thereof include polyolefin and acid-modified polyolefin. That is, the heat-fusible resin layer 3 may contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The thermally fusible resin layer 3 may contain a polyolefin skeleton, for example, by infrared spectroscopy, gas chromatography mass spectrometry, etc., and the analysis method is not particularly limited. For example, when a maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected in the vicinity of wave number 1760 cm −1 and wave number 1780 cm −1. However, if the acid denaturation degree is low, the peak may be small and not detected. In that case, analysis is possible by nuclear magnetic resonance spectroscopy.

  Specific examples of the polyolefin include polyethylenes such as low density polyethylene, medium density polyethylene, high density polyethylene and linear low density polyethylene; homopolypropylene, block copolymers of polypropylene (for example, block copolymers of propylene and ethylene), polypropylene Polypropylenes such as random copolymers (e.g., random copolymers of propylene and ethylene); terpolymers of ethylene-butene-propylene and the like. Among these polyolefins, preferably polyethylene and polypropylene are mentioned, and more preferably polypropylene is mentioned.

  The polyolefin may be a cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin which is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, isoprene and the like. Moreover, as a cyclic monomer which is a constituent monomer of cyclic polyolefin, for example, cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene, etc. may be mentioned. Moreover, styrene is also mentioned as a constituent monomer. Among these, preferably cyclic alkenes, more preferably norbornene are mentioned.

  The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of the above-described polyolefin with a carboxylic acid or the like. Examples of the carboxylic acid used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.

  The acid-modified polyolefin may be an acid-modified cyclic polyolefin. The acid-modified cyclic polyolefin is prepared by copolymerizing some of the monomers constituting the cyclic polyolefin in place of the α, β-unsaturated carboxylic acid or its anhydride, or It is a polymer obtained by block polymerization or graft polymerization of a saturated carboxylic acid or its anhydride. The acid-modified cyclic polyolefin is as described above. Moreover, as a carboxylic acid used for modification | denaturation, it is the same as that used for modification | denaturation of an acid-modified cycloolefin copolymer.

  Among these resin components, preferred are polyolefins; more preferred are propylene copolymers. Propylene copolymers include copolymers of propylene with other olefins such as ethylene-propylene copolymers, propylene-butene copolymers, ethylene-propylene-butene copolymers, and the like. The proportion of the propylene unit contained in polypropylene is preferably about 50 to 100 mol%, more preferably about 80 to 100 mol%, from the viewpoint of further enhancing the insulation and durability of the battery packaging material. . Further, the proportion of ethylene units contained in polyethylene is preferably about 50 to 100 mol%, and preferably about 80 to 100 mol%, from the viewpoint of further enhancing the insulation and durability of the battery packaging material. More preferable. The ethylene copolymer and the propylene copolymer may be either a random copolymer or a block copolymer, and a random propylene copolymer is preferred.

  The heat-fusible resin layer 3 of the present invention preferably contains polypropylene, and preferably has a layer formed of polypropylene. The heat fusible resin layer 3 may be formed of one type of resin component alone, or may be formed of a blend polymer in which two or more types of resin components are combined. Furthermore, the heat-fusible resin layer 3 may be formed of only one layer, but may be formed of two or more layers of the same or different resin components.

In the present invention, from the viewpoint of improving the formability of the battery packaging material, it is preferable that a lubricant be present on the surface of the heat-fusible resin layer 3. The lubricant is not particularly limited, and known lubricants can be used, and examples thereof include those exemplified for the above-mentioned base layer 2. The lubricant may be used alone or in combination of two or more. The amount of the lubricant present on the surface of the heat-fusible resin layer 3 is not particularly limited, but from the viewpoint of enhancing the formability of the battery packaging material, preferably 10 in an environment of 24 ° C. and 60% relative humidity. to 50 mg / m ² about, even more preferably include about 15~40mg / m ^2.

  The heat fusible resin layer 3 may contain a lubricant. Further, the lubricant present on the surface of the heat-fusible resin layer 3 may be one in which the lubricant contained in the resin constituting the heat-fusible resin layer 3 is exuded, or the heat-fusible resin layer The surface of 3 may be coated with a lubricant.

  From the viewpoint of enhancing the formability, the dynamic friction coefficient of the heat fusible resin layer 3 side surface of the battery packaging material of the present invention is preferably about 0.5 or less, more preferably about 0.3 or less, and further preferably Is about 0.2 or less. The lower limit of the dynamic friction coefficient is about 0.01. Moreover, as a preferable range of the said dynamic friction coefficient, about 0.01-0.5, about 0.01-0.3, about 0.01-0.2 is mentioned. In addition, the said dynamic friction coefficient is the value measured based on the method prescribed | regulated to JISK7125: 1999.

  The thickness of the heat fusible resin layer 3 of the present invention is not particularly limited as long as it exhibits the function as a heat fusible resin layer, but from the viewpoint of enhancing formability, for example, about 10 to 40 μm, Preferably about 15-40 micrometers is mentioned.

[Surface covering layer 6]
In the battery packaging material of the present invention, on the base material layer 2 (the aluminum alloy of the base material layer 2 as necessary) for the purpose of improving designability, electrolytic solution resistance, abrasion resistance, moldability, etc. If necessary, a surface coating layer 6 may be provided on the side opposite to the foil 1). The surface covering layer 6 is a layer located in the outermost layer when the battery is assembled.

  The surface coating layer 6 can be formed of, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin or the like. Among these, the surface coating layer 6 is preferably formed of a two-component curable resin. Examples of the two-component curable resin that forms the surface covering layer 6 include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Further, an additive may be blended in the surface coating layer 6.

  Examples of the additive include fine particles having a particle diameter of about 0.5 nm to 5 μm. The material of the additive is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. Further, the shape of the additive is not particularly limited, and examples thereof include spheres, fibers, plates, indeterminate shapes, and balloons. As the additive, specifically, talc, silica, graphite, kaolin, montmorrroid, montmorillonite, synthetic 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, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel and the like can be mentioned. These 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 viewpoint of dispersion stability and cost. In addition, the surface may be subjected to various surface treatments such as insulation treatment, high dispersion treatment, and the like.

  Although it does not restrict | limit especially as a method to form the surface coating layer 6, For example, the method of apply | coating 2-component curable resin which forms the surface coating layer 6 on one surface of the base material layer 2 is mentioned. In the case of blending the additive, the additive may be added to and mixed with the two-component curable resin and then applied.

  The content of the additive in the surface coating layer 6 is not particularly limited, but preferably about 0.05 to 1.0% by mass, more preferably about 0.1 to 0.5% by mass.

  The thickness of the surface coating layer 6 is not particularly limited as long as the above-described function as the surface coating layer 6 is exhibited, and for example, about 0.5 to 10 μm, preferably about 1 to 5 μm.

3. Method for Producing Battery Packaging Material The method for producing the battery packaging material of the present invention is not particularly limited as long as a laminate obtained by laminating each layer of a predetermined composition is obtained, and at least a base material layer and an aluminum alloy The lamination process which obtains the laminated body which foil and a heat-fusible resin layer were equipped in this order is provided, and the method of using the aluminum alloy foil of the present invention as aluminum alloy foil is employable.

  As an example of the manufacturing method of the packaging material for batteries of this invention, it is as follows. First, a laminate (hereinafter sometimes referred to as “laminate A”) including the base material layer 2, the adhesive layer 4 and the aluminum alloy foil 1 in this order is formed. Specifically, the laminate A is formed by extruding an adhesive used for forming the adhesive layer 4 on the base material layer 2 or the aluminum alloy foil 1 whose surface has been subjected to a chemical conversion treatment as required. It can carry out by the dry lamination method which makes the aluminum alloy foil 1 or the substrate layer 2 concerned laminate, and hardens adhesive layer 4 after applying and drying with application methods, such as a coat method and a roll coat method.

  Next, on the aluminum alloy foil 1 of the laminate A, the adhesive layer 5 and the heat fusible resin layer 3 are laminated in this order. For example, (1) a method of laminating the adhesive layer 5 and the heat-fusible resin layer 3 by coextrusion on the aluminum alloy foil 1 of the laminate A (co-extrusion laminating method), (2) separately, an adhesive layer 5. A method of forming a laminate in which the heat fusible resin layer 3 is laminated on the aluminum alloy foil 1 of the laminate A by the thermal lamination method, (3) on the aluminum alloy foil 1 of the laminate A The heat fusible resin layer is formed in advance in a sheet form on the adhesive layer 5 by laminating an adhesive for forming the adhesive layer 5 by an extrusion method or a solution-coated drying or baking method at a high temperature. Method of laminating 3 by the thermal laminating method, (4) Pouring the melted adhesive layer 5 between the aluminum alloy foil 1 of the laminated body A and the heat fusible resin layer 3 previously formed into a sheet. While laminating through the adhesive layer 5 The method of bonding the A and heat-fusible resin layer 3 (sandwich lamination method).

  In the case of providing a surface covering layer, the surface covering layer is laminated on the surface of the base material layer 2 opposite to the aluminum alloy foil 1. The surface coating layer can be formed, for example, by applying the above-mentioned resin that forms the surface coating layer to the surface of the base material layer 2. The order of the step of laminating the aluminum alloy foil 1 on the surface of the base layer 2 and the step of laminating the surface coating layer on the surface of the base layer 2 is not particularly limited. For example, after forming a surface coating layer on the surface of the base layer 2, the aluminum alloy foil 1 may be formed on the surface of the base layer 2 opposite to the surface coating layer.

  The method for causing the lubricant to be present on the surface of the base material layer 2 or the heat fusible resin layer 3 is not particularly limited. For example, the lubricant is mixed with the resin constituting the base material layer 2 or the heat fusible resin layer 3 And, if necessary, a method of exuding a lubricant to the surface, a method of applying a lubricant to the surface of the base layer 2 or the heat fusible resin layer 3, and the like.

  As described above, the surface coating layer 6 provided as necessary, the base material layer 2, the adhesive layer 4 provided as needed, the aluminum alloy foil 1 whose surface is chemically treated as needed, the adhesive layer 5. A laminate having the heat-fusible resin layer 3 in this order is formed, but in order to strengthen the adhesion of the adhesive layer 4 and the adhesive layer 5 provided as required, a heat roll is further provided. It may be subjected to heat treatment such as contact type, hot air type, near or far infrared type or the like. As conditions of such heat processing, about 1 to 5 minutes are mentioned, for example at about 150-250 degreeC.

  In the battery packaging material of the present invention, each layer constituting the laminate improves or stabilizes film forming ability, lamination processing, final product secondary processing (pouching, embossing) suitability, etc., as necessary. For this purpose, surface activation treatments such as corona treatment, blast treatment, oxidation treatment, and ozone treatment may be performed.

4. Applications of Battery Packaging Material The battery packaging material of the present invention is used as a packaging material for sealing and accommodating battery elements such as a positive electrode, a negative electrode, and an electrolyte.

  Specifically, a battery element comprising at least a positive electrode, a negative electrode, and an electrolyte is a battery packaging material of the present invention, in which the metal terminal connected to each of the positive electrode and the negative electrode protrudes outward. The battery is covered by forming flanges (areas in which the heat fusible resin layers are in contact with each other) on the periphery of the element, and heat sealing the heat fusible resin layers of the flanges to seal them. A battery using a packaging material is provided. In addition, when accommodating a battery element using the battery packaging material of this invention, it is used so that the heat fusible resin part of the battery packaging material of this invention may become inside (surface which contacts a battery element).

  The battery packaging material of the present invention may be used for either a primary battery or a secondary battery, but is preferably a secondary battery. The type of secondary battery to which the battery packaging material of the present invention is applied is not particularly limited. For example, lithium ion batteries, lithium ion polymer batteries, lead storage batteries, nickel hydrogen storage batteries, nickel cadmium storage batteries And nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, multivalent cation batteries, capacitors, capacitors and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are mentioned as a suitable application object of the packaging material for batteries of the present invention.

  Hereinafter, the present invention will be described in detail by showing Examples and Comparative Examples. However, the present invention is not limited to the examples.

Examples 1 to 7 and Comparative Examples 1 to 4
As a resin film which comprises a base material layer, biaxially stretched nylon film (25 micrometers in thickness) was used. Corona treatment is applied to one side of the biaxially stretched nylon film. Erucic acid amide was applied as a lubricant (coating amount: 10 mg / m ² ) on the side of the biaxially stretched nylon film which was not subjected to corona treatment. On the other hand, the thickness of the adhesive layer consisting of a polyester polyol-based main agent and an aromatic isocyanate-based two-component urethane adhesive cured on the surface of the biaxially stretched nylon film subjected to corona treatment is 3 μm after curing It applied so that it might become. Next, each aluminum alloy foil having the characteristics described in Table 1 is prepared, the adhesive layer side of the base material layer and the chemical conversion treated surface of the aluminum alloy foil are laminated, and pressure heating is applied, and then aging is performed. By carrying out the treatment, a laminate in which the biaxially stretched nylon film / adhesive layer / aluminum alloy foil were laminated in order was produced. The chemical conversion treatment of aluminum alloy foil is carried out by a roll coating method so that the coating amount of chromium is 10 mg / m ² (dry mass) of a treatment liquid consisting of a phenol resin, a chromium fluoride compound and phosphoric acid. It was done by applying and baking on both sides of the foil. In addition, the aluminum alloy foils of Examples 1 to 7 and Comparative Examples 1 to 4 are manufactured by the above-mentioned known method while adjusting the composition, rolling conditions, and the like, respectively. It has different characteristics.

  In addition, separately, co-extrusion of acid-modified polypropylene resin (unsaturated carboxylic acid graft-modified random polypropylene grafted with unsaturated carboxylic acid) and polypropylene (random copolymer) constituting the heat-fusible resin layer constituting the adhesive layer. By doing this, a two-layer coextruded film comprising a 20 μm thick adhesive layer and a 20 μm thick heat fusible resin layer was produced. Next, the adhesive layer of the two-layer coextruded film prepared above is superposed and heated on the aluminum alloy foil side of the laminate of the biaxially stretched nylon film / adhesive layer / aluminum alloy foil described above and in contact with it. As a result, a laminate was obtained in which the base material layer (biaxially stretched nylon film) / adhesive layer / aluminum alloy foil / adhesive layer / heat sealable resin layer were laminated in order. The obtained laminate was once cooled and then subjected to heat treatment to obtain packaging materials for the respective batteries.

<Measurement of Proportion of Total Area of {111} Plane, Number Average Grain Size, and Standard Deviation of Grain Size>
The crystal analysis is performed by EBSD method on the cross section in the direction perpendicular to the rolling direction of each aluminum alloy foil used above, and the ratio of the total area of the {111} plane of aluminum alloy foil, number average crystal grain size, and crystal grain The standard deviation of diameter was measured. Details of the measurement conditions are as follows. The measurement results are shown in Table 1. When the maximum crystal grain size was measured for reference when measuring the number average crystal grain size, the maximum crystal grain size of the aluminum alloy foil of Example 1 was 8.6 μm, and the maximum of the aluminum alloy foil of Comparative Example 3 The crystal grain size was 12.5 μm. The number average crystal grain size is a diameter when assuming an area calculated by [(measurement area-area of CI value 0.1 or less area) / number of crystals] to be a circle, and obtained by crystal analysis by EBSD method It is the number average crystal grain size of the crystals contained in the measurement area of approximately 10000 μm ² or more by connecting a plurality of images. The maximum crystal grain size is a value measured for the largest crystal among the crystals included in the measurement area, assuming that the crystal shape is a circle. The standard deviation of the crystal grain size is a crystal included in a measurement area of about 10000 μm ² or more by connecting a plurality of images obtained by crystal analysis by the EBSD method after removing the area having a CI value of 0.1 or less. It calculated from distribution of crystal grain size (diameter when crystal area is assumed to be a circle).

(measuring device)
An apparatus equipped with an EBSD detector (manufactured by TSL Solutions, Inc.) is used as a Schottky field emission scanning electron microscope.

(Preprocessing)
As pretreatment, the aluminum alloy foil is cut in the direction perpendicular to the rolling direction (RD) to obtain a cross section. The rolling direction of the aluminum alloy foil is a direction in which a linear rolling mark extends when the shiny surface of the aluminum alloy foil is observed with a metallographic microscope. As a specific procedure, first, an aluminum alloy foil as a sample was cut out to 5 mm (direction perpendicular to the rolling direction) × 10 mm (rolling direction) with a trimming razor and embedded in a resin. Next, using a trimming razor, the aluminum alloy foil is cut together with the resin in a direction perpendicular to the rolling direction of the aluminum alloy foil and perpendicularly from the surface of the aluminum alloy foil to expose the cross section of the aluminum alloy foil I did. Next, the obtained cross section is trimmed using a microtome (Ultra Microtome manufactured by Leica Microsystems). In this trimming, in order to reduce the mechanical distortion of the cross-sectional shape, a microtome was cut along with the embedded resin in a direction perpendicular to the cross section by about 1 mm. Next, using a ion milling apparatus (manufactured by Hitachi High-Technologies Corporation), a broad argon beam was irradiated in the direction perpendicular to the cross section under the conditions of a protrusion width of 50 μm and a voltage of 6 kV for 4 hours to prepare a measurement cross section. . This is an operation of precisely exposing the cross section of the aluminum alloy foil so as to minimize the breakdown to the mechanical crystal structure occurring in the previous step.

(SEM conditions)
The conditions of the scanning electron microscope (SEM) used for the EBSD method are as follows.
Observation magnification: 2000 times acceleration voltage: 15kV
Working distance: 15 mm
Inclination angle: 70 °

(EBSD condition)
The conditions for crystal analysis by EBSD method are as follows.
Step size: 200 nm
Analysis condition:
The following analysis was performed using crystal orientation analysis software OIM (Ver. 7.3) manufactured by TSL Solutions, Inc.
A plurality of images were connected, and the measurement area was about 10000 μm ² or more. At this time, from the center to both ends in the thickness direction of the aluminum alloy foil was used as a measurement area, and the part where the resin was attached to the cross section and the part where the acid resistant film was present were excluded from the measurement area.
After connecting the images, the pole figure was confirmed.
The analysis was performed excluding the data whose reliability index (Confidence Index: CI value) CI value defined by crystal orientation analysis software OIM manufactured by TSL Solutions, Inc. is 0.1 or less.
In the calculation of the percentage of the total area of the {111} plane, the analysis was performed at an allowable angle of 15 °.

  A graph showing the relationship between the thickness X (μm) of the aluminum alloy foils of Examples 1 to 7 and Comparative Examples 1 to 4 and the ratio (%) of the total area of the {111} planes is shown in FIG. In FIG. 8, a reference straight line of the ratio (%) of the total area of the {111} plane = −1.1 × + 66 is drawn. In FIG. 8 to FIG. 11, 〇 is the result of the example, and Δ is the result of the comparative example.

Moreover, the graph which shows the relationship between thickness X (micrometer) of the aluminum alloy foil of Examples 1-7 and Comparative Examples 1-4, and number average crystal grain diameter R (micrometer) is shown in FIG. In FIG. 9, the number average crystal grain size R = 0. 0 56X + 2.0 reference straight line is drawn.

  The graph which shows the relationship between thickness X (micrometer) of the aluminum alloy foil of Examples 1-7 and Comparative Examples 1-4, and the standard deviation of a crystal grain size is shown in FIG. In FIG. 10, a reference straight line with a standard deviation of the grain size of St = 0.09 × 0.5 is drawn.

<Measurement of critical forming depth>
Each of the battery packaging materials obtained above was cut into strips of 150 mm (TD) x 100 mm (MD) to prepare test samples. The MD of the battery packaging material corresponds to the rolling direction (RD) of the aluminum alloy foil, and the TD of the battery packaging material corresponds to the TD of the aluminum alloy foil. Further, the same plane perpendicular direction to MD and RD is TD. The rolling direction of the aluminum alloy foil can be confirmed by the rolling marks of the aluminum alloy foil. The mold used was a straight mold consisting of a 30 mm (MD) × 50 mm (TD) rectangular male mold and a female mold having a clearance of 0.5 mm between the male mold. The test sample was placed on the female mold so that the heat-fusible resin layer side was positioned on the male mold side. The test sample was pressed at a surface pressure of 0.1 MPa and cold-formed (one-step drawing) so as to obtain a predetermined forming depth. The cold-formed sample was exposed to light with penlight in a dark room, and it was confirmed by light transmission whether the aluminum alloy foil had pinholes or cracks. Number of samples in which pinholes etc. occurred in the shallowest forming depth where Amm is the deepest forming depth where pinholes and cracks do not occur in all 10 samples in aluminum alloy foil and pinholes etc in aluminum alloy foil B pieces, and the value calculated by the following formula was made into the limit forming depth of the packaging material for batteries. The results are shown in Table 1.
Limiting molding depth = A mm + (0.5 mm / 10 pieces) × (10 pieces-B pieces)

<Evaluation of formability>
The relationship between the limit forming depth of each of the battery packaging materials of Examples 1 to 7 and Comparative Examples 1 to 4 and the thickness X (μm) of the aluminum alloy foil is plotted in the graph of FIG. Since the critical forming depth changes with the thickness of the aluminum alloy foil, in order to evaluate the formability independent of thickness, the following two criteria were provided for the forming depth. In addition, the reference reference line of the following reference | standard 2 was shown in FIG.
Criterion 1: Forming depth (mm) = thickness of aluminum alloy foil X (μm) × 0.14 + 2
Reference 2: forming depth (mm) = thickness of aluminum alloy foil X (μm) × 0.12 + 2
Based on these criteria 1 and 2, the formability of the packaging material for each battery of Examples 1 to 7 and Comparative Examples 1 to 4 was evaluated according to the following criteria. The results are shown in Table 1.
a: Critical forming depth (mm) 厚 み thickness of aluminum alloy foil X (μm) × 0.14 + 2
b: Thickness of aluminum alloy foil X (μm) × 0.14 + 2> limit forming depth (mm) 厚 み thickness of aluminum alloy foil X (μm) × 0.1 2 + 2
c: Thickness of aluminum alloy foil X (μm) × 0.1 2 + 2> critical forming depth (mm)

From the results shown in Table 1, according to the EBSD method, a cross section obtained by cutting the aluminum alloy foil in a direction perpendicular to the rolling direction of the aluminum alloy foil and perpendicular to the surface of the aluminum alloy foil The ratio of the total area of {111} planes to the total area of the crystal planes of the face-centered cubic lattice structure obtained by conducting crystal analysis is 10% or more, and the crystal analysis by EBSD method for the cross section Examples 1 to 7 in which the number average crystal grain size R of the crystal of the face-centered cubic lattice structure obtained by performing the above satisfies the condition of “number average crystal grain size R ≦ 0.056 × + 2.0” It is understood that any battery packaging material using the aluminum alloy foil of the above is excellent in formability.
On the other hand, although the proportion of the total area of {111} planes is 10% or more, Comparative Example 1 in which the number average crystal grain size R does not satisfy the condition of “number average crystal grain size R ≦ 0.056 X + 2.0”. The battery packaging materials of ~ 4 were all inferior in formability to the examples.

DESCRIPTION OF SYMBOLS 1 Aluminum alloy foil 1a ... Section 2 ... Base material layer 3 ... Thermal adhesive resin layer 4 ... Adhesive layer 5 ... Adhesive layer 6 ... Surface coating layer 10 ... Packaging material T for batteries ... Roll marks

Claims (9)

An aluminum alloy foil for use in a battery packaging material,
Acquired by performing crystal analysis by EBSD on a cross section obtained by cutting the aluminum alloy foil in a direction perpendicular to the rolling direction of the aluminum alloy foil from the surface of the aluminum alloy foil. The ratio of the total area of {111} planes to the total area of crystal planes of face-centered cubic lattice structure is 10% or more, and
The number average crystal grain size R (μm) of the crystal of the face-centered cubic lattice structure obtained by performing crystal analysis by the EBSD method for the cross section satisfies the following expression .
Number average crystal grain size R ≦ 0.056 × + 2.0
X = thickness (μm) of the aluminum alloy foil, 10 μm or more
An aluminum alloy foil for a packaging material for a battery, wherein the ratio (%) of the total area of {111} planes to the total area of crystal planes of the face-centered cubic lattice structure satisfies the following equation.
Ratio (%) of total area of {111} planes to total area of crystal planes of face-centered cubic lattice structure ≧ −1.1 × + 66
X = thickness (μm) of the aluminum alloy foil, 10 μm or more The aluminum alloy foil for battery packaging materials according to claim 1, wherein the standard deviation St of the crystal grain size satisfies the following equation.
Standard deviation of crystal grain size St ≦ 0.09 × + 0.5
X = thickness of the aluminum alloy foil (μm) The aluminum alloy foil for battery packaging materials according to claim 1 or 2 , which contains iron. The battery packaging material according to any one of claims 1 to 3 , wherein an acid resistant film comprising at least one element selected from the group consisting of phosphorus, chromium and cerium is provided on the surface of the aluminum alloy foil. Aluminum alloy foil. An acid resistant coating is provided on the surface of the aluminum alloy foil,
For the acid-resistant coating, flight when analyzed with time-of secondary ion mass spectrometry, a peak derived from at least one of Ce ⁺ and Cr ⁺ is detected, according to any of claims 1 to 3 Aluminum alloy foil for packaging materials for batteries. On the surface of the aluminum alloy foil, phosphorus compounds, chromium compounds, fluorides, and an acid-resistant coating comprising at least one member selected from the group consisting of a triazine thiol compound, in any one of claims 1 to 3 Aluminum alloy foil for packaging materials for batteries as described. The aluminum alloy foil for battery packaging materials according to any one of claims 1 to 3 , wherein an acid resistant coating containing a cerium compound is provided on the surface of the aluminum alloy foil. A packaging material for a battery, comprising a laminate including at least a base material layer, an aluminum alloy foil for a packaging material for a battery according to any one of claims 1 to 7 , and a heat-fusible resin layer in this order. . A battery, wherein a battery element comprising at least a positive electrode, a negative electrode, and an electrolyte is contained in a package formed of the battery packaging material according to claim 8 .