CN104769141B - Aluminium alloy foil - Google Patents

Abstract

An aluminum alloy foil, the chemical composition of which contains, by mass %, Si: 0.1% to 0.6%, Fe: 0.2% to 1.0%, the remainder being Al and unavoidable impurities; the thickness of the foil is 20 μm or less ; In the case where the boundary between adjacent crystal orientation measurement points is 5°±0.2° defined as the grain boundary, the area ratio of the subgrain with a grain size of 2 μm or less is 40% or more; tensile strength It is above 210MPa; the specific resistance measured in liquid nitrogen is above 0.45μΩ·cm and below 0.7μΩ·cm.

Description

Aluminum alloy foil

technical field

The invention relates to an aluminum alloy foil.

Background technique

Conventionally, aluminum alloy foils have been used in various fields. In recent years, aluminum alloy foils have been used as, for example, secondary batteries such as lithium-ion batteries and current collectors such as electric double-layer capacitors from the viewpoint of being thin and having conductivity. Specifically, in the case of a lithium ion battery, as disclosed in Patent Document 1 and Patent Document 2, one surface of an aluminum alloy foil serving as a current collector is coated with a positive electrode active material and a binder. layer, dried, and rolled to increase the density of the positive electrode active material and the adhesion to the foil, thereby manufacturing the positive electrode.

As the above-mentioned aluminum alloy foil, for example, Patent Document 3 discloses an aluminum alloy foil for lithium ion batteries that contains Si: 0.01-0.60% by mass, Fe: 0.2-1.0% by mass, Cu: 0.05-0.50 % by mass, Mn: 0.5 to 1.5% by mass, the remainder is formed of Al and unavoidable impurities, the tensile strength is 240 MPa or more, and the n value is 0.1 or more.

In addition, in Patent Document 4, although it does not disclose an aluminum alloy foil for lithium ion batteries, it discloses an aluminum alloy foil for porous processing that contains Si: 0.05 to 0.30% by mass, Fe: 0.15 ~0.60% by mass, Cu: 0.01~0.20% by mass, the remainder is formed of Al and unavoidable impurities, the tensile strength is about 186~212N/mm ² , and the foil thickness is about 30μm~100μm.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2007-234277

Patent Document 2: Japanese Patent Application Laid-Open No. 11-67220

Patent Document 3: Japanese Patent Laid-Open No. 2011-26656

Patent Document 4: Japanese Patent Laid-Open No. 2006-283114

Contents of the invention

However, conventional aluminum alloy foils have problems in the following points. That is, as described above, when manufacturing parts using foil such as battery electrodes, the aluminum alloy foil receives compressive force due to rolling or the like. Therefore, the aluminum alloy foil needs to have sufficient strength so that unnecessary deformation or breakage does not occur against such a compressive force. In recent years, foil has been required to be thinner, and in order to cope with this problem, further improvement in strength is desired.

As a typical method for achieving high strength of foil, there is a method of adjusting the composition of the aluminum alloy. However, simply adjusting the alloy components will increase the specific resistance of the foil and lower the conductivity due to the addition of alloy components other than Al. As described above, conventional aluminum alloy foils have a problem that it is difficult to achieve further improvement in strength without greatly losing electrical conductivity.

In view of the above background, the present invention provides an aluminum alloy foil capable of further improving strength without greatly losing electrical conductivity.

An aluminum alloy foil according to an embodiment of the present invention is characterized in that the chemical composition of the aluminum alloy foil contains Si: 0.1% to 0.6%, Fe: 0.2% to 1.0%, and the remainder is Al and unavoidable impurities are formed; the thickness of the foil is 20 μm or less; the grain size is 2 μm or less when the boundary where the orientation difference between adjacent crystal orientation measurement points is 5°±0.2° is defined as a grain boundary The area ratio of the subcrystals is more than 40%; the tensile strength is more than 210MPa; the specific resistance measured in liquid nitrogen is more than 0.45μΩ·cm and less than 0.7μΩ·cm.

Since the above-mentioned aluminum alloy foil has the above-mentioned specific characteristics, it is possible to further increase the strength without greatly losing electrical conductivity. Since the above-mentioned aluminum alloy foil can exert sufficient strength by further increasing the strength, unnecessary plastic deformation can be suppressed even when a compressive force is applied by rolling or the like when manufacturing parts using foil such as battery electrodes, It is also easy to realize thinning of the foil. Furthermore, the aluminum alloy foil described above can secure good electrical conductivity without greatly losing electrical conductivity even if its strength is increased. Therefore, if the above-mentioned aluminum alloy foil is used, for example, as a current collector of an electrode in a secondary battery such as a lithium ion battery, it can contribute to higher density and higher energy of the battery.

Description of drawings

1 is a graph showing the results of measuring the area ratio of subgrains with a grain size of 2 μm or less by the SEM/EBSD method for the test material E11 in Example 1. FIG.

2 is a graph showing the results of measuring the area ratio of subgrains with a grain size of 2 μm or less by the SEM/EBSD method for the test material C1 in Example 1. FIG.

detailed description

The meaning and reason of the limitation of the specific chemical component in the said aluminum alloy foil (the unit is mass %, and only abbreviate|omits as "%" in the following description of a chemical component) are as follows.

Si: 0.1% to 0.6%

Si is an essential element for achieving improved foil strength. When producing foil, if the temperature of the aluminum alloy exceeds 350°C, solid-solution Si and Fe will precipitate as Al-Fe-Si-based compounds, thereby reducing the work hardenability during cold rolling and easily reducing the strength of the foil. . Therefore, it is preferable not to perform homogenization treatment at high temperature when manufacturing foil, but to perform hot rolling under the condition of 350°C or less, but in order to increase the strength of the foil under this condition, reduce the specific resistance of the foil and ensure electrical conductivity , it is necessary to set the Si content to 0.1% to 0.6%. If the Si content is less than 0.1%, the specific resistance of the foil will be lowered, but the strength of the foil will not be improved. If the Si content exceeds 0.6%, it will be difficult to further increase the strength of the foil, and coarse Si single-phase particles will be formed, and pinholes and foil cracks will easily occur when the foil thickness is 20 μm or less. The Si content may preferably be 0.12% or more. The Si content may preferably be 0.4% or less.

Fe: 0.2% to 1.0%

Fe is an essential element next to Si for achieving improved foil strength. When the temperature of the aluminum alloy exceeds 350° C. during foil production, solid-solution Si and Fe are precipitated as Al—Fe—Si compounds, which reduces work hardening during cold rolling and tends to lower the strength of the foil. Therefore, it is preferable not to perform homogenization treatment at a high temperature exceeding 350°C when manufacturing the foil, but to perform hot rolling under the condition of 350°C or lower, but in order to increase the strength of the foil under this condition and reduce the specific resistance of the foil And to ensure electrical conductivity, it is necessary to make the Fe content 0.2% or more and 1.0% or less. If the Fe content is less than 0.2%, the specific resistance of the foil will be lowered, but the strength of the foil will not be improved. If the Fe content exceeds 1.0%, it will be difficult to further improve the foil strength, and coarse Al-Fe-based crystals will be formed during casting. As mentioned above, unless the aluminum alloy ingot is homogenized at a high temperature exceeding 350°C, the Al-Fe-based crystals formed during casting remain in a coarse state and remain in the final foil thickness. Therefore, when the foil thickness is 20 μm or less, problems of pinholes and foil cracks tend to occur. Furthermore, adding Fe more than necessary will cause an increase in manufacturing cost. The Fe content may preferably be 0.30% or more. The Fe content may preferably be 0.80% or less.

The above-mentioned chemical components may further contain Cu: not less than 0.01% and not more than 0.25% by mass%. The meaning in this case and the reason for the limitation are as follows.

Cu: 0.01% to 0.25%

Cu is an element that contributes to improving foil strength. In order to obtain this effect, the Cu content is preferably 0.01% or more. In addition, less than 0.01% of Cu may be contained as an unavoidable impurity. On the other hand, if the Cu content is too large, the strength of the foil will be increased, but the specific resistance will also be increased. Therefore, the Cu content is preferably 0.25% or less. The Cu content may preferably be 0.02% or more. The Cu content may preferably be 0.18% or less.

Among the above chemical components, elements such as Mn, Mg, Cr, Zn, Ni, Ga, V, Ti, etc. may be contained as unavoidable impurities. However, when Mn and Mg are contained excessively, the specific resistance of the foil may increase and the electrical conductivity may decrease. Therefore, the Mn content is preferably 0.01% or less, and the Mg content is preferably 0.01% or less. Since other elements such as Cr, Zn, Ni, Ga, V, and Ti are relatively unfavorable elements for increasing the specific resistance, the content of each element is preferably 0.05% or less. In addition, if the total content of all unavoidable impurities is 0.15% or less, it is acceptable because it does not substantially affect improvement in foil strength or conductivity.

In the aluminum alloy foil described above, the foil thickness is 20 μm or less. If the foil thickness exceeds 20 μm, it cannot cope with thinning of the foil (foil thickness gauge down (gauge down)) which has been frequently demanded in recent years. The above-mentioned aluminum alloy foil is particularly suitable for use as a current collector of a battery electrode, for example, where a high thickness reduction of the foil is required, since the foil thickness thereof is 20 μm or less. From the standpoint of thinning the wall and contributing to the miniaturization of batteries, etc., the foil thickness of the aluminum alloy foil is preferably less than 20 μm, more preferably 19 μm or less, further preferably 18 μm or less, and still more preferably 17 μm or less. 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, for example, in the production of components using foil, such as when manufacturing batteries.

In the above-mentioned aluminum alloy foil, when the boundary between adjacent crystal orientation measurement points is defined as a grain boundary where the orientation difference is 5° ± 0.2°, the area ratio of the subgrains with a grain size of 2 μm or less is 40 %above. Specifically, by using a scanning electron microscope/electron backscatter diffraction (Electron Back Scatter Diffraction) method (SEM/EBSD method), a 900 μm ² The area of the crystal orientation is analyzed, and the boundary between the adjacent crystal orientation measurement points is 5 ° ± 0.2 ° as the grain boundary, and the subgrain with a grain size of 2 μm or less in the area of the above measurement area is calculated. The proportion (%) of the area, so that the area ratio of the above-mentioned sub-grains can be obtained.

If the area ratio of the subgrains is less than 40%, the tensile strength of the foil will decrease, and the strength of the foil will decrease. From the viewpoint of further improving the strength, the area ratio of the subgrains may be preferably 45% or more, more preferably 50% or more, and still more preferably 55% or more. In addition, the higher the value of the area ratio of the subgrains, the better, and ideally 100%, but from the viewpoint of actual production, the upper limit may be 80% or less.

In the above-mentioned aluminum alloy foil, the tensile strength thereof is 210 MPa or more. When the tensile strength is less than 210 MPa, it cannot be said that further improvement in strength has been achieved. Furthermore, when the tensile strength is less than 210 MPa, unnecessary plastic deformation tends to occur when a compressive force is applied to the foil by rolling or the like, for example, when thinning the foil. The aforementioned tensile strength may be preferably 213 MPa or higher, more preferably 215 MPa or higher, and still more preferably 220 MPa or higher. In addition, although the upper limit of the tensile strength is not particularly limited, the most suitable range can be determined in consideration of the balance with the specific resistance and the like. The tensile strength may be, for example, about 330 MPa or less. In addition, the tensile strength is a value measured according to JIS (Japanese Industrial Standard) Z2241.

In the aluminum alloy foil described above, the specific resistance is not less than 0.45 μΩ·cm and not more than 0.7 μΩ·cm. In addition, the above-mentioned specific resistance is a value measured in liquid nitrogen. The purpose of measuring the specific resistance in liquid nitrogen is to eliminate the influence of the measurement environment temperature.

The specific resistance is related to the solid solution amount of Si and Fe in the alloy composition. When the specific resistance is within the above-mentioned range, it is easy to realize that the strength can be further improved without greatly losing the electrical conductivity. If the specific resistance is less than 0.45 μΩ·cm, it will be difficult to improve the strength by work hardening during foil production, and it will be difficult to make the tensile strength 210 MPa or more. The specific resistance may be preferably 0.50 μΩ·cm or more, more preferably 0.55 μΩ·cm or more. On the other hand, when the specific resistance becomes higher, the strength can be improved by work hardening at the time of producing the foil, but the specific resistance tends to increase and the conductivity decreases. Therefore, the specific resistance can be set to about 60% of the specific resistance of the 3003-series aluminum alloy foil, which is considered to be a relatively high-strength aluminum alloy foil, that is, about 0.7 μΩ·cm. The specific resistance may preferably be 0.69 μΩ·cm or less, more preferably 0.68 μΩ·cm or less. In addition, specific resistance can be measured by a two-arm bridge method in accordance with JIS H0505.

The aluminum alloy foil described above can be used for a current collector of a battery electrode. In this case, the electrode active material adheres to the surface of the aluminum alloy foil as the current collector. Specifically, in this case, on the surface of the aluminum alloy foil, a layer containing an electrode active material is coated, and compressive force is applied by rolling or the like after drying. Even in such a case, since the above-mentioned aluminum alloy foil is unlikely to undergo unnecessary plastic deformation due to compressive force, the electrode active material is unlikely to be peeled off, and good electrical conductivity can also be ensured. Furthermore, since the above-mentioned aluminum alloy foil has foil strength, it is also easy to respond to requests for thinning of the foil. Therefore, in this case, it is possible to contribute to higher density and higher energy of secondary batteries such as lithium ion batteries.

For example, the aluminum alloy foil mentioned above can be manufactured as follows. That is, the above-mentioned aluminum alloy foil can be obtained by hot-rolling an aluminum alloy ingot having the above-mentioned specific chemical composition and then performing cold rolling including foil rolling.

At this time, hot rolling may be performed without performing homogenization treatment at high temperature on the aluminum alloy ingot. Hot rolling starts after heating to a temperature of 350° C. or lower, and the temperatures at the start of hot rolling, during hot rolling, and at the end of hot rolling may all be 350° C. or lower. The holding time after reaching the hot rolling start temperature is not particularly limited, but may be within 12 hours from the viewpoint of easily suppressing the precipitation of Al—Fe—Si based compounds. In addition, hot rolling may be performed once, or may be divided into several times and performed, such as finishing rolling after rough rolling.

In addition, annealing is not performed in the middle of cold rolling, and the foil thickness is 20 μm or less. This is because if the annealing is performed in the middle, the precipitation of the Al-Fe-Si type compound will be accelerated, the work hardening property at the time of cold rolling will fall, and it will cause the fall of foil strength. In addition, for the same reason as the intermediate annealing, it is also preferable not to perform the final annealing after completion of the cold rolling. From the standpoint of improving foil strength, etc., the final rolling ratio of cold rolling is preferably 90% or more, more preferably 95% or more. The final rolling ratio is calculated by 100×(thickness of the hot-rolled sheet before cold rolling-foil thickness of the aluminum alloy foil after the final cold-rolling)/(thickness of the hot-rolled sheet before cold-rolling ) calculated value. Furthermore, in foil rolling with a thickness of 200 μm or less, the temperature of the foil before foil rolling, rolling rate, rolling speed, cooling by rolling oil, etc. can be adjusted so that the temperature during foil rolling is Below 120°C. This is because it is easy to make the area ratio of the subgrains having a crystal grain size of 2 μm or less be 40% or more.

The aluminum alloy foil concerning an Example is demonstrated below.

(Example 1)

Aluminum alloy ingots of the chemical compositions shown in Table 1 were ingoted and cut using a semi-continuous casting method to prepare aluminum alloy ingots. In addition, among the aluminum alloys having chemical compositions shown in Table 1, alloys A to K are aluminum alloys having chemical compositions suitable for Examples, and alloys L to Q are aluminum alloys having chemical compositions as comparative examples.

【Table 1】

The above-prepared aluminum alloy ingot was hot-rolled without homogenization treatment to obtain a hot-rolled sheet having a thickness of 2 mm. At this time, the hot rolling is continuously performed with rough rolling and finish rolling. In addition, in the hot rolling described above, the rough rolling start temperature (hot rolling start temperature) was set to 350° C. by heating the aluminum alloy ingot before rough rolling to 350° C. and holding it for 6 hours. Furthermore, the finish temperature of rough rolling (intermediate temperature of hot rolling) was set to 320°C, and the finish temperature of finish rolling (finish temperature of hot rolling) was set to 278°C. In this example, not only the start temperature and end temperature of hot rolling but also the middle temperature of hot rolling, that is, the end temperature of rough rolling, that is, the start temperature of finish rolling is 350° C. or less.

Next, cold rolling including foil rolling was repeatedly performed without performing annealing on the way, to obtain an aluminum alloy foil with a foil thickness of 12 μm. At this time, in the foil rolling step of 200 μm or less, the finishing temperature of the foil rolling is adjusted to 120° C. or less. In addition, the final rolling ratio of the above-mentioned cold rolling is 100×(2000 μm plate thickness of the hot-rolled sheet before cold rolling−foil thickness 12 μm of the aluminum alloy foil after the final cold rolling)/(before cold rolling The plate thickness of the hot-rolled plate (2000 μm) = 99.4%.

Next, using the obtained aluminum alloy foil as a test material, the tensile strength, yield strength, elongation, specific resistance (resistivity), and area ratio of subgrains with a grain size of 2 μm or less were measured. Specifically, according to JISZ2241, a JIS No. 5 test piece was collected from the test material to measure the tensile strength, yield strength, and elongation. According to JISH0505, the specific resistance was measured using a two-arm bridge method. In addition, in order to eliminate the influence of ambient temperature, the measurement of specific resistance was carried out in liquid nitrogen. After the final treatment of the surface of the sample by electropolishing (10V-90 seconds of electropolishing in perchloric acid ethanol cooled to -5°C), the SEM/EBSD method was used to test the sample at a step size of 0.1 μm. Analyze the area of 900 μm2 ^on the surface of the sample, and regard the boundary where the orientation difference between adjacent crystal orientation measurement points is 5°±0.2° as the grain boundary, and calculate that the grain size in the area of the above measurement area is 2 μm or less The ratio (%) of the area occupied by the subgrains was calculated to obtain the area ratio of the subgrains with a grain size of 2 μm or less. In addition, in order to investigate the foil rolling condition, light was irradiated from the back surface of the test material, and the occurrence of pinholes was also investigated based on the presence or absence of light leakage. The results are shown in Table 2. In addition, FIG. 1 shows the results of measuring the area ratio of subgrains having a crystal grain size of 2 μm or less using the SEM/EBSD method for the test material E11. In FIG. 2 , the results of measuring the area ratio of the subgrains having a crystal grain size of 2 μm or less for the test material C1 using the SEM/EBSD method are shown. In both figures, subgrains with a grain size of 2 μm or less are indicated in gray. In addition, test materials E1 to E11 are examples, and test materials C1 to C4 are comparative examples.

【Table 2】

As shown by these results, test material C1 used alloy L having a Si content of less than 0.1% and an Fe content of less than 0.2%, and the area ratio of subgrains having a grain size of 2 μm or less was as low as 25%. Therefore, in the test material C1, the effect of further improving the strength could not be obtained, and its tensile strength was as low as less than 210 MPa.

Since the test material C2 used the alloy M having a Si content exceeding 0.6%, coarse Si single-phase particles were formed, thereby generating pinholes.

In test material C3, alloy N having an Fe content of less than 0.2% was used, and the area ratio of subgrains having a grain size of 2 μm or less was as low as less than 40%. Therefore, in the test material C3, the effect of further improving the strength could not be obtained, and its tensile strength was as low as less than 210 MPa.

Since the test material C4 used alloy O with an Fe content exceeding 1.0%, coarse Al—Fe-based particles were formed, thereby generating pinholes.

In contrast, test materials E1 to E11 were all made of alloys A to K containing the above-mentioned specific chemical components, the foil thickness was 20 μm or less, the area ratio of subgrains with a grain size of 2 μm or less was 40% or more, and the tensile strength was 40%. The strength is above 210MPa. Furthermore, the specific resistances of the test materials E1 to E11 measured in liquid nitrogen were all 0.45 μΩ·cm to 0.7 μΩ·cm, and it was found that the electrical conductivity did not significantly decrease.

Therefore, according to this example, there can be provided an aluminum alloy foil capable of further improving strength without greatly losing electrical conductivity. It is believed that the reason why such an aluminum alloy foil can be obtained is that when the foil thickness is 20 μm or less after 95% or more cold rolling, the recovery of the structure is slow, and a fine subgrain structure appears, thereby enhancing the effect. Furthermore, even if the aluminum alloy foil is thinned, it has high strength, and problems such as pinholes and foil cracks can be avoided.

(Example 2)

An ingot of an aluminum alloy B having the chemical composition shown in Table 1 was ingoted and cut using a semi-continuous casting method to prepare an aluminum alloy ingot. In addition, aluminum alloy ingots for comparison were prepared together by cutting ingots of 1050 alloy (alloy P) and 3003 alloy (alloy Q) of the conventional alloys shown in Table 1 using a semi-continuous casting method.

An aluminum alloy foil having a foil thickness of 12 μm was produced under the production conditions shown in Table 3 using the aluminum alloy ingot prepared above. For the obtained aluminum alloy foil, in the same manner as in Example 1, its tensile strength, yield strength, elongation, specific resistance (resistivity), and the area ratio of subgrains with a grain size of 2 μm or less were measured, and foil rolling was investigated. Control status (with or without pinholes). The results are shown in Table 4. In addition, test materials E12 and E13 are examples, and test materials C5 to C12 are comparative examples.

【table 3】

【Table 4】

As shown in Table 4, since the hot rolling start temperature of test materials C5 to C7 exceeded 350°C during hot rolling, the area ratio of subgrains with a grain size of 2 μm or less was less than 40%, and the tensile strength was as low as Less than 210MPa.

Test material C8 was produced by performing a homogenization treatment at 520° C. before starting hot rolling. Therefore, in test material C8, an Al-Fe-Si compound was formed, the solid solution amount of Si and Fe decreased, the area ratio of subgrains with a grain size of 2 μm or less was less than 40%, and the tensile strength was as low as less than 210 MPa.

The test material C9 was produced by annealing at 380° C. at a plate thickness of 1 mm in the middle of cold rolling. Therefore, in Test Material C9, precipitation of Al-Fe-Si-based compounds was accelerated, the area ratio of subgrains with a grain size of 2 μm or less was less than 40%, and the tensile strength was as low as less than 210 MPa.

The cold rolling completion temperature of the test material C10 at the time of manufacture was 130 degreeC. Therefore, in the test material C10, the area ratio of subgrains with a grain size of 2 μm or less was less than 40%, and the tensile strength was as low as less than 210 MPa.

Test materials C11 and C12 were produced by using conventional alloys 1050 alloy (alloy P) and 3003 alloy (alloy Q), and further homogenizing at a high temperature of 500°C exceeding 350°C before starting hot rolling. . Therefore, since the chemical composition of test material C11 is the same as that of the conventional alloy 1050 (alloy P), its tensile strength does not reach 210 MPa, and the area ratio of subgrains with a grain size of 2 μm or less is less than 40%. Since the chemical composition of the test material C12 is the same as that of the conventional alloy 3003 alloy (alloy Q), its specific resistance is very high at 1.2 μΩ·cm or more, and its electrical conductivity is poor.

In contrast, the test materials E12 and E13 are both made of alloy B containing the above-mentioned specific chemical composition, the foil thickness is 20 μm or less, the area of subgrains with a grain size of 2 μm or less is 40% or more, and the tensile strength is 210 MPa above. In addition, the specific resistances of the test materials E12 and E13 measured in liquid nitrogen were both 0.45 μΩ·cm to 0.7 μΩ·cm, and it was found that the electrical conductivity did not significantly decrease.

Therefore, according to this example, there can be provided an aluminum alloy foil capable of further improving strength without greatly losing electrical conductivity.

Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within a range not detracting from the gist of the present invention.

Claims (3)

1. a kind of alloy foil, it is characterised in that include：

Its chemical composition is by containing Si based on coming by quality %：Less than more than 0.1% 0.6%, Fe：Less than more than 0.2% 1.0%, Remainder is formed for Al and inevitable impurity；

Paper tinsel thickness is less than 20 μm；

Misorientation between the crystal orientation measurement point that will abut against is paper tinsel in the case that 5 ° ± 0.2 ° of border is defined as crystal boundary It is more than 40% that the crystallite dimension on surface is the area ratio of less than 2 μm of subgrain；

Tensile strength is more than 210MPa；

The ratio resistance measured in liquid nitrogen is below 0.7 μ Ω cm of more than 0.45 μ Ω cm.

2. alloy foil according to claim 1, it is characterised in that

The chemical composition by quality % come based on further contain Cu：Less than more than 0.01% 0.25%.

3. the alloy foil according to claims 1 or 2, it is characterised in that

The alloy foil is used for the collector of battery electrode.