JP2014109057A - Aluminum alloy foil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy foil capable of achieving to make high strength without seriously spoiling conductivity.SOLUTION: An aluminum alloy foil has a chemical component containing, by mass%, Si: 0.1% to 0.6%, Fe: 0.2% to 1.5%, the sum of the Si content and the Fe content of 0.48% or more, and the balance Al with inevitable impurities, and the foil thickness of 20 μm or less, the solid solution amount of Si of 700 mass ppm or more, the solid solution amount of Fe of 150 mass ppm or more, tensile strength of 220 MPa or more and specific electric resistance measured in liquid nitrogen of 0.45 μΩ cm to 0.7 μΩ cm.

Description

  The present invention relates to an aluminum alloy foil.

  Conventionally, aluminum alloy foil has been used in various fields. In recent years, aluminum alloy foils are used, for example, as current collectors for electrodes in power storage devices such as lithium ion batteries, electric double layer capacitors, and lithium ion capacitors from the viewpoint of being thin and conductive. Specifically, for example, as disclosed in Patent Documents 1 and 2, after applying a layer containing a positive electrode active material and a binder on one surface of an aluminum alloy foil as a current collector, and drying, The positive electrode of the lithium ion battery as an electrical storage device is manufactured by rolling in order to improve the density of a positive electrode active material, and the adhesiveness to foil.

  As said aluminum alloy foil, for example, in patent document 3, Si: 0.01-0.60 mass%, Fe: 0.2-1.0 mass%, Cu: 0.05-0.50 mass% , Mn: Aluminum alloy for lithium ion batteries containing 0.5 to 1.5 mass%, the balance being Al and inevitable impurities, tensile strength is 240 MPa or more, and n value is 0.1 or more A foil is disclosed.

In addition, there are the following two other technical documents preceding the present application. Patent Document 4 is not an aluminum alloy foil for a lithium ion battery, but the document includes Si: 0.05 to 0.30 mass%, Fe: 0.15 to 0.60 mass%, Cu: 0.00. Disclosed is an aluminum alloy foil for porous processing containing 01 to 0.20% by mass, the balance being made of Al and inevitable impurities, a tensile strength of about 186 to 212 N / mm ² , and a foil thickness of about 30 μm to 100 μm. Has been.

  Patent Document 5 contains Fe: 0.1 to 2.5% by mass and Si: 0.01 to 0.5% as an aluminum alloy plate that can be used as a foil material, with the balance being Al and inevitable. An aluminum alloy sheet that is an impurity and has a solid solution Fe amount of 200 ppm or more and is cold-rolled without being hot-rolled is disclosed.

JP 2007-234277 A Japanese Patent Laid-Open No. 11-67220 JP 2011-26656 A JP 2006-283114 A Japanese Patent Laid-Open No. 2008-223075

  However, the conventional aluminum alloy foil has problems in the following points. That is, as described above, the aluminum alloy foil receives a compressive force by rolling or the like when manufacturing a foil-use member such as an electrode of an electricity storage device. Therefore, the aluminum alloy foil is required to have sufficient strength so as not to cause unnecessary deformation and breakage against such a compressive force. In recent years, further thinning of the foil has been demanded, and in order to cope with this, it is desired to increase the strength of the foil.

  As a typical method for increasing the strength of the foil, there is a method of adjusting an aluminum alloy component. However, by simply adjusting the alloy components, the specific resistance of the foil increases due to the addition of alloy components other than Al, and the conductivity decreases. Thus, the conventional aluminum alloy foil has a problem that it is difficult to increase the strength without significantly impairing the electrical conductivity.

  The present invention has been made in view of such a background, and has been obtained in an attempt to provide an aluminum alloy foil capable of achieving high strength without significantly impairing electrical conductivity.

  In one embodiment of the present invention, the chemical component contains, in mass%, Si: 0.1% to 0.6%, Fe: 0.2% to 1.5%, and Si content and Fe content The total amount is 0.48% or more, the balance is made of Al and inevitable impurities, the foil thickness is 20 μm or less, the solid solution amount of Si is 700 mass ppm or more, and the solid solution amount of Fe is 150 mass. The aluminum alloy foil is characterized by having a ppm or higher, a tensile strength of 220 MPa or higher, and a specific resistance measured in liquid nitrogen of 0.45 μΩ · cm or more and 0.7 μΩ · cm or less. 1).

  Since the said aluminum alloy foil has the said specific structure, it can attain high intensity | strength, without impairing electroconductivity largely. Therefore, the aluminum alloy foil can suppress unnecessary plastic deformation, for example, even when a compressive force is applied by rolling or the like when manufacturing a foil-use member such as an electrode of an electricity storage device. It will be easier to realize. In addition, the aluminum alloy foil can ensure good conductivity without being greatly impaired in conductivity even when the strength is increased. Therefore, if the said aluminum alloy foil is used as an electrical power collector of the electrode in electrical storage devices, such as a lithium ion battery, for example, it can contribute to the high density and high energy increase of an electrical storage device.

It is explanatory drawing for demonstrating the schematic procedure at the time of measuring Si solid solution amount and Fe solid solution amount in an Example.

  The significance and reason for limitation of the specific chemical component (unit is mass%, in the description of the chemical component below, simply abbreviated as “%”) in the aluminum alloy foil are as follows.

Si: 0.1% to 0.6% Si is an element necessary for improving the foil strength. If the temperature of the aluminum alloy exceeds 350 ° C. during the production of the foil, the dissolved Si and Fe are likely to precipitate as Al—Fe—Si based compounds, thereby reducing the work hardening during cold rolling. The foil strength tends to decrease. Therefore, it is desirable not to perform homogenization at a high temperature exceeding 350 ° C. during foil production, but to perform hot rolling under conditions of 350 ° C. or lower. However, under these conditions, the foil strength is increased and the specific resistance of the foil is reduced. And in order to ensure electroconductivity, it is necessary to make Si content into 0.1% or more and 0.6% or less. When the Si content is less than 0.1%, the specific resistance of the foil is reduced, but the strength of the foil is not improved. When the Si content exceeds 0.6%, it is difficult to further improve the foil strength, and coarse Si single-phase particles are formed. If the foil thickness is 20 μm or less, the problem of pinholes and foil breakage tends to occur. The Si content is preferably 0.12% or more. The Si content is preferably 0.4% or less.

Fe: 0.2% or more and 1.5% or less Fe is an element necessary for improving the foil strength after Si. If the temperature of the aluminum alloy exceeds 350 ° C. during the production of the foil, the dissolved Si and Fe are likely to precipitate as Al—Fe—Si based compounds, thereby reducing the work hardening during cold rolling. The foil strength tends to decrease. For this reason, it is desirable to perform hot rolling under conditions of 350 ° C. or lower without performing homogenization at a high temperature exceeding 350 ° C. during foil production, but under these conditions, the foil strength is increased and the specific resistance of the foil is reduced. In order to ensure conductivity, the Fe content needs to be 0.2% or more and 1.5% or less. When the Fe content is less than 0.2%, the specific resistance of the foil is reduced, but the strength of the foil is not improved. If the Fe content exceeds 1.5%, it is difficult to further improve the foil strength, and a coarse Al—Fe crystallized product is formed during casting. As described above, when the homogenization treatment is not performed on the aluminum alloy ingot at a temperature higher than 350 ° C., the Al—Fe crystallized product formed at the time of casting remains in a coarse state up to the final foil thickness. Will do. Therefore, the problem of pinholes and foil breakage tends to occur at a foil thickness of 20 μm or less. Moreover, addition of Fe more than necessary also causes an increase in manufacturing cost. The Fe content is preferably 0.30% or more. The Fe content is preferably 1.2% or less, more preferably 1.0% or less, and even more preferably 0.80% or less.

Total of Si content and Fe content: 0.48% or more The total of Si content and Fe content (hereinafter sometimes referred to as “Si + Fe amount”) ensures a tensile strength of 220 MPa or more. Is important above. When the amount of Si + Fe is less than 0.48%, a tensile strength of 220 MPa or more cannot be obtained, and it becomes difficult to increase the strength. The amount of Si + Fe is preferably 0.49% or more, more preferably 0.5% or more, and further preferably 0.52% or more, from the viewpoint of easily securing a tensile strength of 220 MPa or more. In consideration of the Si content, the upper limit of the Fe content, and the like, the Si + Fe content is preferably 1.6% or less, preferably 1.4% or less, more preferably 1.2% or less. Good.

  The said chemical component can further contain Cu: 0.01% or more and 0.25% or less by the mass% (Claim 2). The significance and reasons for limitation in this case are as follows.

Cu: 0.01% or more and 0.25% or less Cu is an element that contributes to improving the strength of the foil. In order to obtain the effect, the Cu content is preferably 0.01% or more. Note that Cu of less than 0.01% may be included as an inevitable impurity. On the other hand, when the Cu content is excessive, the strength of the foil increases, but the specific resistance also increases. Therefore, the Cu content is preferably 0.25% or less. The Cu content is preferably 0.02% or more. The Cu content is preferably 0.18% or less.

  The chemical component can contain elements such as Mn, Mg, Cr, Zn, Ni, Ga, V, and Ti as inevitable impurities. However, if Mn and Mg are excessively contained, the specific resistance of the foil is increased and the electrical conductivity may be deteriorated. Therefore, it is preferable that the Mn content is 0.01% or less and the Mg content is 0.01% or less. Since other elements such as Cr, Zn, Ni, Ga, V, and Ti are elements that do not contribute to the increase in specific resistance, the content of each element is preferably 0.05% or less. Further, if the total content of inevitable impurities as a whole is 0.15% or less, it can be tolerated because it does not substantially affect conductivity and increase in strength.

  In the aluminum alloy foil, the foil thickness is 20 μm or less. If the foil thickness exceeds 20 μm, it cannot cope with the thinning of the foil (foil thickness gauge down), which is often required in recent years. Since the aluminum alloy foil has a foil thickness of 20 μm or less, for example, the aluminum alloy foil is particularly suitable for use as a current collector for an electricity storage device electrode that requires a large thickness of the foil. In the aluminum alloy foil, the thickness of the foil is preferably less than 20 μm, more preferably 19 μm or less, still more preferably 18 μm or less, and even more preferably 17 μm or less, from the viewpoint of reducing the thickness and contributing to downsizing of the electricity storage device. It can be. On the other hand, the thickness of the foil is preferably 8 μm or more, more preferably 9 μm or more, and even more preferably 10 μm or more from the viewpoint of ease of handling at the time of manufacturing a foil using member such as an electrode of an electricity storage device. .

  In the aluminum alloy foil, the solid solution amount of Si is 700 mass ppm or more, and the solid solution amount of Fe is 150 mass ppm or more. When the solid solution amount of Si is less than 700 ppm by mass and the solid solution amount of Fe is less than 150 ppm by mass, it becomes impossible to achieve a high strength with a tensile strength of 220 MPa or more. The solid solution amount of Si is preferably 720 ppm by mass or more, more preferably 740 ppm by mass or more, and further preferably 760 ppm by mass or more, from the viewpoint of ensuring the above-described increase in strength. In addition, although the amount of solid solution of Si is so preferable that the value is high, the upper limit can be 1000 mass ppm or less from a viewpoint of the cooling rate at the time of ingot formation, etc. on actual manufacture. On the other hand, the solid solution amount of Fe is preferably 170 ppm by mass or more, more preferably 190 ppm by mass or more, and further preferably 200 ppm by mass or more from the viewpoint of ensuring the high strength. In addition, although the solid solution amount of Fe is so preferable that the value is high, the upper limit can be 500 mass ppm or less from viewpoints, such as a cooling rate at the time of agglomeration, in actual manufacture.

  Basically, the solid solution amount of Si and the solid solution amount of Fe can be measured by the following method. That is, using a hot phenol dissolution extraction method, an Al—Fe compound and an Al—Fe—Si compound contained in a test piece collected from an aluminum alloy foil are obtained as a residue. And Si and Fe are melt | dissolved from the said residue by this hot phenol melt | dissolution extraction method, the quantitative analysis by an inductively coupled plasma emission spectrometry (ICP) is performed, and Si precipitation amount and Fe precipitation amount which precipitated as the said compound are calculated | required. Moreover, Si single phase particle | grains contained in the test piece extract | collected from the aluminum alloy foil are obtained as a residue using hydrochloric acid melt | dissolution extraction method. And the said residue by this hydrochloric acid melt | dissolution extraction method is melt | dissolved, the quantitative analysis by ICP is performed, and Si precipitation amount precipitated as Si single phase particle | grains is calculated | required. The sum of the Si precipitation amount obtained by the hot phenol dissolution extraction method and the Si precipitation amount obtained by the hydrochloric acid dissolution extraction method is taken as the total Si precipitation amount. Moreover, let Fe precipitation amount obtained by the hot phenol melt | dissolution extraction method be Fe total precipitation amount. The value obtained by subtracting the total Si precipitation amount from the Si component analysis value of the aluminum alloy foil is defined as the Si solid solution amount. Further, a value obtained by subtracting the total Fe precipitation amount from the Fe component analysis value of the aluminum alloy foil is defined as an Fe solid solution amount.

  In the aluminum alloy foil, the tensile strength is 220 MPa or more. If the tensile strength is less than 220 MPa, it cannot be said to be the high strength referred to in the present application. The tensile strength is preferably 223 MPa or more, more preferably 225 MPa or more, and further preferably 230 MPa or more. The upper limit of the tensile strength is not particularly limited, but can be determined within an optimum range in consideration of the balance with the specific resistance. The tensile strength can be, for example, about 340 MPa or less. The tensile strength is a value measured according to JIS Z2241.

  In the aluminum alloy foil, the specific resistance is 0.45 μΩ · cm or more and 0.7 μΩ · cm or less. The specific resistance is a value measured in liquid nitrogen. The specific resistance is measured in liquid nitrogen in order to remove the influence of the measurement ambient temperature.

  The specific resistance correlates with the solid solution amount of Si and Fe as alloy components. When the specific resistance is within the above range, the strength can be increased without significantly degrading the conductivity. When the specific resistance is less than 0.45 μΩ · cm, it is difficult to work and harden at the time of manufacturing the foil, and the tensile strength is hardly set to 220 MPa or more. The specific resistance is preferably 0.50 μΩ · cm or more, more preferably 0.55 μΩ · cm or more. On the other hand, when the specific resistance is high, it is easy to work and harden at the time of manufacturing the foil, and it is easy to increase the strength, but there is a tendency for the conductivity to decrease. Therefore, the specific resistance is preferably about 0.7 μΩ · cm, which is about 60% of the specific resistance of the 3003 series aluminum alloy foil, which is a relatively high strength aluminum alloy foil. The specific resistance is preferably 0.69 μΩ · cm or less, more preferably 0.68 μΩ · cm or less. The specific resistance can be measured by a double bridge method in accordance with JIS H0505.

  The aluminum alloy foil can be used for a current collector of an electricity storage device electrode (claim 3). In this case, an electrode active material is attached to the surface of the aluminum alloy foil as a current collector. Specifically, in this case, a layer containing an electrode active material is applied to the surface of the aluminum alloy foil, and a compressive force by rolling or the like is applied after drying. Even in such a case, the aluminum alloy foil is unlikely to undergo unnecessary plastic deformation due to the compressive force, so that the electrode active material is difficult to peel off, and good electrical conductivity can be secured. Moreover, since the said aluminum alloy foil is excellent in foil strength, it is easy to respond to the request | requirement of foil thinning. Therefore, in this case, it can contribute to high density and high energy storage devices such as lithium ion batteries.

  The aluminum alloy foil can be produced, for example, as follows. That is, the aluminum alloy foil can be obtained by hot rolling an aluminum alloy ingot composed of the specific chemical component and then performing cold rolling including foil rolling.

  At this time, the aluminum alloy ingot is preferably hot-rolled without performing homogenization at a high temperature exceeding 350 ° C. Hot rolling starts after heating to a temperature of 350 ° C. or lower, and the temperature at the start of hot rolling, during hot rolling, and at the end of hot rolling can be 350 ° C. or lower. . Although the holding time after reaching the hot rolling start temperature is not particularly limited, it may be within 12 hours from the viewpoint of facilitating the precipitation of the Al—Fe—Si compound. it can. Note that the hot rolling may be performed once, or may be performed in a plurality of times, such as finish rolling after rough rolling.

  In the cold rolling, the foil thickness is set to 20 μm or less without annealing in the middle. When annealing is performed in the middle, precipitation of the Al—Fe—Si-based compound is promoted, and work hardening at the time of cold rolling is lowered, resulting in a decrease in foil strength. In addition, it is preferable not to perform the final annealing after completion | finish of cold rolling for the same reason as intermediate annealing. The final rolling rate in cold rolling including foil rolling is preferably 95% or more, more preferably 96% or more, and still more preferably 97% or more, from the viewpoint of increasing the tensile strength of 220 MPa or more. it can. Final rolling rate is 100 × (plate thickness of hot rolled plate before cold rolling−foil thickness of aluminum alloy foil after final cold rolling) / (plate thickness of hot rolled plate before cold rolling) It is a value calculated from

  The aluminum alloy foil according to the example will be described below.

Example 1
An aluminum alloy ingot was prepared by ingot forming and chamfering an aluminum alloy having chemical components shown in Table 1 by a semi-continuous casting method. Of the aluminum alloys having chemical components shown in Table 1, alloys A to H are aluminum alloys having chemical components suitable for the examples, and alloys I to O are aluminum alloys having chemical components as comparative examples.

  The prepared aluminum alloy ingot was hot-rolled without subjecting it to a homogenization treatment to obtain a hot-rolled plate having a thickness of 2 mm. At this time, in hot rolling, rough rolling and finish rolling were continuously performed. In the hot rolling, the aluminum alloy ingot before being subjected to the rough rolling is heated to 330 ° C. and held for 6 hours to set the rough rolling start temperature (hot rolling start temperature) to 330 ° C. . The end temperature of rough rolling (temperature during hot rolling) was 310 ° C., and the end temperature of finish rolling (end temperature of hot rolling) was 270 ° C. As described above, in this example, not only the hot rolling start temperature and end temperature, but also the rough rolling end temperature, which is the intermediate temperature of hot rolling, that is, the finish rolling start temperature, is set to 330 ° C. or less.

  Subsequently, after returning to room temperature, cold rolling including foil rolling was repeatedly performed without annealing in the middle to obtain an aluminum alloy foil having a foil thickness of 12 μm. The final rolling rate in the cold rolling is 100 × (the thickness of the hot rolled sheet before cold rolling is 2000 μm−the thickness of the aluminum alloy foil after the final cold rolling is 12 μm) / (before the cold rolling) The thickness of the hot-rolled sheet is 2000 μm) = 99.4%.

  Next, using the obtained aluminum alloy foil as a test material, tensile strength, yield strength and elongation, specific resistance (electrical resistivity), Si solid solution amount, and Fe solid solution amount were measured. Specifically, the tensile strength, proof stress, and elongation were measured in accordance with JIS Z2241, and a JIS No. 5 test piece was collected from the test material and n = 2. The specific resistance was measured by a double bridge method according to JIS H0505. In order to remove the influence of the ambient temperature, the specific resistance was measured in liquid nitrogen.

  The Si solid solution amount and the Fe solid solution amount were measured according to the following procedure. This will be described with reference to FIG. FIG. 1 describes a method for analyzing the total Si precipitation amount and the total Fe precipitation amount in an aluminum alloy foil from the residue obtained by the hot phenol dissolution extraction method and the residue obtained by the hydrochloric acid dissolution extraction method. . In addition, the analysis method of Si precipitation amount and Fe precipitation amount is the academic literature of "Sato, Izumi: The Light Metal Society of Japan 68th Spring Conference Outline, (1985), 55.", "Muramatsu, Matsuo, Komatsu et al .: Light Metal Society of Japan. The academic literature of the 76th Spring Conference Lecture Summary, (1989), 51. "can be referred to.

  First, the hot phenol dissolution extraction method will be described. A 2 g test piece was collected from the aluminum alloy foil (S10). In addition, the test piece cut out the small piece from the aluminum alloy foil, and weighed it so that it might become 2g in total. Next, a beaker containing 50 ml of phenol was placed on a hot plate and the phenol was heated to 170 ° C. to 180 ° C., and then a test piece was added and dissolved (S11). Next, the beaker containing the above solution was lowered from the hot plate and cooled (S12). Next, benzyl alcohol was added to the cooled solution to prevent solidification (S13). Next, the solution to which the benzyl alcohol was added was filtered through a polytetrafluoroethylene membrane filter (pore size: 0.1 μm) (S14) to obtain an Al—Fe compound and an Al—Fe—Si compound as a residue. (S15). Next, Si was dissolved in a 10% -NaOH solution from the residue obtained by this hot phenol dissolution extraction method, and then Fe was dissolved in aqua regia (concentrated hydrochloric acid: concentrated nitric acid = 3: 1 by volume). A mixed liquid containing dissolved Si and Fe was obtained. Next, this mixed solution was quantitatively analyzed by inductively coupled plasma optical emission spectrometry (ICP) (S16). Thereby, the amount of Si deposited and the amount of Fe deposited as Al—Fe compounds and Al—Fe—Si compounds were determined.

Next, the hydrochloric acid dissolution extraction method will be described. A 2 g test piece was collected from the aluminum alloy foil (S20). In addition, the test piece was extract | collected similarly to the above. Next, the test piece was placed in a beaker containing 120 ml of HCl (concentrated hydrochloric acid: water = 1: 1 by volume) and dissolved at room temperature, and ₂ to 3 drops of hydrogen peroxide water H ₂ O ₂ was added. (S21). Next, the solution was filtered through a polytetrafluoroethylene membrane filter (pore size: 0.1 μm) (S24) to obtain Si single-phase particles as a residue (S25). Next, the residue obtained by this hydrochloric acid dissolution extraction method was dissolved in a 10% -NaOH solution, and then mixed with the aqua regia to acidify to pH 1-2. Next, this solution was quantitatively analyzed by inductively coupled plasma optical emission spectrometry (ICP) (S26). Thereby, the amount of Si deposited as Si single phase particles was determined.

  Next, the sum of the Si precipitation amount obtained by the hot phenol dissolution extraction method and the Si precipitation amount obtained by the hydrochloric acid dissolution extraction method was taken as the total Si precipitation amount. Further, the Fe precipitation amount obtained by the hot phenol dissolution extraction method was defined as the total Fe precipitation amount. The value obtained by subtracting the total Si precipitation amount from the Si component analysis value of the aluminum alloy foil was defined as the Si solid solution amount. Further, the value obtained by subtracting the total Fe precipitation amount from the Fe component analysis value of the aluminum alloy foil was defined as the Fe solid solution amount.

  In addition, in order to investigate the foil rolling situation, lighting was applied from the back of the test material, and the occurrence of pinholes was also investigated according to the presence or absence of light leakage. The above results are summarized in Table 2.

  As shown in these results, since the test material C1 used the alloy I whose Si + Fe amount was 0.47%, the tensile strength was as low as less than 220 MPa.

  The test material C2 uses an alloy J having an Si content of less than 0.1% and an Fe content of less than 0.2%, an Si solid solution content of less than 700 mass ppm, and an Fe solid solution content of 150 mass. Less than ppm. Therefore, the test material C2 has a low tensile strength of less than 220 MPa.

  Since the test material C3 used an alloy K having an Si content exceeding 0.6%, coarse Si single-phase particles were formed, and pinholes were generated due to this.

  The test material C4 uses an alloy L having an Fe content of less than 0.2%, and the Fe solid solution content is less than 150 mass ppm. Therefore, the test material C3 had a low tensile strength of less than 220 MPa.

  Since the test material C5 used the alloy M in which the Fe content exceeded 1.5%, coarse Al—Fe-based particles were formed, and pinholes were generated thereby.

  On the other hand, the test materials E1 to E8 are all made of the alloys A to H having the specific chemical components described above, the foil thickness is 20 μm or less, the Si solid solution amount is 700 mass ppm or more, and the Fe solid solution. The amount is 150 ppm by mass or more and the tensile strength is 220 MPa or more. In addition, the test materials E1 to E8 all have a specific resistance measured in liquid nitrogen of 0.45 μΩ · cm to 0.7 μΩ · cm. From this result, it can be seen that the electrical conductivity of the test materials E1 to E8 is not greatly reduced despite the high tensile strength of 220 MPa or more.

  Therefore, according to this example, it is possible to provide an aluminum alloy foil capable of achieving high strength without greatly impairing conductivity. Moreover, since the aluminum alloy foil has high strength even if it is thinned, problems such as pinholes and foil breakage can also be avoided.

(Example 2)
An aluminum alloy ingot was prepared by ingot forming and chamfering aluminum alloy A having chemical components shown in Table 1 by a semi-continuous casting method. In addition, a comparative aluminum alloy ingot was prepared by ingot forming and chamfering 1050 alloy (alloy N) and 3003 alloy (alloy O) of conventional alloys shown in Table 1 by a semi-continuous casting method. .

  Using the prepared aluminum alloy ingot, an aluminum alloy foil having a foil thickness of 12 μm was produced under the production conditions shown in Table 3. In addition, the cold rolling in Table 3 was started after returning to room temperature. For the obtained aluminum alloy foil, the tensile strength, proof stress and elongation, specific resistance (electrical resistivity), Si solid solution amount and Fe solid solution amount were measured in the same manner as in Example 1, and the foil rolling situation (pin pole) Existence of occurrence) was investigated. The results are summarized in Table 4.

  As shown in Table 4, since the test materials C6 to C8 had a hot rolling start temperature of over 350 ° C. during hot rolling, formation of an Al—Fe—Si based compound was promoted, and the amount of Si solid solution Was less than 700 ppm by mass, the Fe solid solution was less than 150 ppm by mass, and the tensile strength was less than 220 MPa.

  The test material C9 was produced by performing a homogenization treatment at 520 ° C. before the start of hot rolling. Therefore, in the test material C9, the formation of an Al—Fe—Si-based compound is promoted, the Si solid solution amount is less than 700 mass ppm, the Fe solid solution amount is less than 150 mass ppm, and the tensile strength is less than 220 MPa. It was.

  The test material C10 has a hot rolling start temperature of 340 ° C., and is produced by performing annealing at 380 ° C. in the middle of cold rolling at a plate thickness of 1 mm. Therefore, in the test material C10, the formation of the Al—Fe—Si compound is promoted, the Si solid solution amount is less than 700 mass ppm, the Fe solid solution amount is less than 150 mass ppm, and the tensile strength is less than 220 MPa. It was.

  As test materials C11 and C12, 1050 alloy (alloy N) and 3003 alloy (alloy O), which are conventional alloys, are used, and further homogenized at a high temperature of 520 ° C. exceeding 350 ° C. before the start of hot rolling. It was produced. Since the test material C11 has the same chemical composition as the conventional alloy 1050 alloy (alloy N), the test material C11 was as low as less than 220 MPa. Since the test material C12 had the same chemical composition as the conventional alloy 3003 alloy (alloy O), the specific resistance was as extremely high as 1.2 μΩ · cm or more, and the conductivity was poor.

  On the other hand, the test materials E9 and E10 are both made of the alloy A having the specific chemical component described above, the foil thickness is 20 μm or less, the solid solution amount of Si is 700 mass ppm or more, and the solid solution amount of Fe is It is 150 mass ppm or more and the tensile strength is 220 MPa or more. The test materials E9 and E10 both have a specific resistance measured in liquid nitrogen of 0.45 μΩ · cm to 0.7 μΩ · cm. From this result, it can be seen that the test materials E9 and E10 do not have a significant decrease in conductivity despite the fact that the tensile strength is increased to 220 MPa or more.

  Therefore, according to this example, it is possible to provide an aluminum alloy foil capable of achieving high strength without greatly impairing conductivity.

  As mentioned above, although the Example was described, this invention is not limited by the said Example, A various deformation | transformation can be performed within the range which does not impair the meaning of this invention.

Claims (3)

The chemical component contains Si: 0.1% or more and 0.6% or less, Fe: 0.2% or more and 1.5% or less, and the total of Si content and Fe content is 0. 48% or more, the balance consisting of Al and inevitable impurities,
The foil thickness is 20 μm or less,
The solid solution amount of Si is 700 mass ppm or more, the solid solution amount of Fe is 150 mass ppm or more,
The tensile strength is 220 MPa or more,
An aluminum alloy foil characterized by having a specific resistance measured in liquid nitrogen of 0.45 μΩ · cm to 0.7 μΩ · cm. In the aluminum alloy foil according to claim 1,
The aluminum alloy foil, wherein the chemical component further contains Cu: 0.01% or more and 0.25% or less by mass%.   The aluminum alloy foil according to claim 1 or 2 is used for a current collector of an electricity storage device electrode.

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