KR101314696B1 - Aluminum alloy foil for current collector and method for producing the same - Google Patents

Abstract

Compared with pure aluminum foil, corrosion resistance does not fall, compared with the conventional aluminum alloy foil for collectors, even if the thickness is 15 micrometers or less, it does not break in the manufacturing process of an electrode, and the electrical resistivity value is a comparatively low value The composition of the aluminum alloy foil for electrical power collectors which can be made is provided. The aluminum alloy foil for collectors is 0.3 mass%-3.0 mass% or less of iron, 0.8 mass% or more and 1.5 mass% or less of silicon, 0.0001 mass% or more and 0.011 mass% or less of copper, and 0.0001 mass% or more and 0.6 mass% or less Aluminum alloy foil for current collectors containing manganese, 0.0001% by mass or more and 0.011% by mass or less, magnesium, and 0.001% by mass or more and 0.011% by mass or less, and the balance includes aluminum and unavoidable impurities. The average diameter of the large diameter crystallized substance which exists in foil is 0.005 micrometer or more and 10 micrometers or less.

Description

Aluminum alloy foil for current collector and its manufacturing method {ALUMINUM ALLOY FOIL FOR CURRENT COLLECTOR AND METHOD FOR PRODUCING THE SAME}

BACKGROUND OF THE INVENTION Field of the Invention The present invention generally relates to an aluminum alloy foil for current collectors and a method for manufacturing the same, and specifically, for current collector aluminum, which is used as a material for forming a current collector for positive electrode of a secondary battery such as a lithium ion battery. An alloy foil and its manufacturing method are related.

As a high capacity secondary battery, a lithium ion battery is not only used for a power source of a portable electronic device, but in recent years, development for use as a power source for a hybrid vehicle has been developed. Conventionally, aluminum foil or aluminum alloy foil is used as a material which forms the electrical power collector for positive electrodes of a lithium ion battery.

For example, as described in Japanese Patent Laid-Open No. 2005-133207 (Patent Document 1), as a base material for a positive electrode of a lithium ion secondary battery, pure aluminum (JIS nominal 1000 series) foil and Al-Mn type (JIS nominal 3000 series) Alloy foil and Al-Fe type (JIS nominal 8000 series) alloy foil are used.

Further, as described in JP-A-2009-64560 (Patent Document 2) and JP-A-2009-81110 (Patent Document 3), the thickness of the foil is 15 µm or less. Even as an aluminum alloy foil for electrical power collectors which does not break even in the manufacturing process of an electrode, the novel Al-Mn-Fe type alloy foil is proposed.

Patent Document 1: Japanese Patent Publication No. 2005-133207 Patent Document 2: Japanese Patent Publication No. 2009-64560 Patent Document 3: Japanese Patent Laid-Open No. 2009-81110

In recent years, in response to the demand for higher capacity and smaller size of a secondary battery, a method of increasing the capacity per volume of the secondary battery by making the current collector thinner has been studied.

However, when the thickness of the aluminum foil or aluminum alloy foil which forms an electrical power collector is made thinner than 20 micrometers, an electrode, such as the process of apply | coating various active materials to the surface of foil, the process of crimping the applied active material to the surface of foil, etc. In the manufacturing process of, there is a problem that the foil is frequently broken.

In general, Al-Mn-based and Al-Fe-based aluminum alloy foils have superior strength in tensile tests as compared to pure aluminum foils. However, if the thickness of the aluminum alloy foil is made thinner than 20 µm, the fracture resistance is excellent. Since the fall was not sufficient, it was not enough to solve the problem of the foil breaking frequently in the electrode manufacturing process.

In addition, the Al-Mn-based and Al-Fe-based aluminum alloy foils have a lower corrosion resistance to the electrolyte than pure aluminum foils. Thus, for example, long lifespan is required, such as a secondary battery used as a power source for hybrid automobiles. It is difficult to use for the electrical power collector of a secondary battery.

In addition, the Al-Mn-based aluminum alloy foil had a high electrical resistivity due to Mn contained therein, and a thinner thickness of 20 µm or less increased the electrical resistivity, causing the current collector to generate heat during charge and discharge. . It is well known that when a current collector generates heat, the performance of a secondary battery, for example, a charge / discharge rate, a battery life, or the like, is impaired.

Therefore, the object of the present invention is that the corrosion resistance is not lowered as compared with the pure aluminum foil, and even when the thickness of the foil is 15 µm or less as compared with the conventional aluminum alloy foil for current collectors, the electrode is not broken in the manufacturing process of the electrode. It is to provide an aluminum alloy foil for current collector and a method for producing the same, which can make the specific resistance value relatively low.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, as a result of examining in various ways, in this aluminum alloy foil, at least content of iron, silicon, copper, manganese, magnesium, and zinc, and the large diameter crystallized substance which exists in an aluminum alloy foil ( By controlling the diameter of a large product, even if the thickness of the aluminum alloy foil is 15 µm or less, the tensile strength and fracture strength necessary to prevent the electrode from being broken in the manufacturing process of the electrode, and to prevent excessive heat generation of the charge discharge It was found that the electrical resistivity value and corrosion resistance required for the same were obtained at the same time. This invention is made | formed based on the knowledge of this inventor.

The aluminum alloy foil for collectors which concerns on this invention is 0.3 mass% or more and 3.0 mass% or less of iron, 0.8 mass% or more and 1.5 mass% or less of silicon, 0.0001 mass% or more and 0.011 mass% or less of copper, and 0.0001 mass% or more As aluminum alloy foil for electrical power collectors which contain 0.6 mass% or less manganese, 0.0001 mass% or more and 0.011 mass% or less magnesium, and 0.001 mass% or more and 0.011 mass% or less, and remainder contain aluminum and an unavoidable impurity. And the average diameter of the large diameter crystallized substance which exists in this aluminum alloy foil is 0.005 micrometer or more and 10 micrometers or less.

Preferably, the aluminum alloy foil for electrical power collectors of this invention contains 0.005 mass% or more and 0.5 mass% or less of titanium.

Moreover, Preferably, the aluminum alloy foil for electrical power collectors of this invention contains 0.0001 mass% or more and 0.3 mass% or less zirconium.

Preferably, the aluminum foil for current collectors of the present invention preferably has a thickness of 1 µm or more and 15 µm or less, tensile strength of 170 N / mm 2 or more and 280 N / mm 2 or less, elongation of 4% or more and 10% or less, and 350 times of fracture strength. It is 1200 times or more and electric resistance value is 2.7 micrometer cm or more and less than 3.7 micrometer cm.

The manufacturing method of the aluminum alloy foil for electrical power collectors which concerns on this invention is a manufacturing method of the aluminum alloy foil for electrical power collectors which has any one of the above characteristics, and comprises the following processes.

(A) The process of obtaining the ingot of an aluminum alloy by casting the molten aluminum alloy at the thickness of 3 mm or more and 10 mm or less with the cooling rate of 100 degrees-C / sec or more and 500 degrees-C / sec or less.

(B) The process of rolling said ingot.

As mentioned above, since the aluminum alloy foil for electrical power collectors of this invention is excellent in tensile strength and abrasion resistance, it can prevent fracture | rupture in the manufacturing process of an electrode, even if the thickness of aluminum alloy foil is 15 micrometers or less. In addition, since the aluminum foil for electrical power collectors of this invention does not fall in corrosion resistance compared with pure aluminum foil, and has a comparatively low electrical resistivity value, for example, when it is used for the electrical power collector of a battery, Excessive heat generation can be prevented. These can use the aluminum foil for electrical power collectors of this invention for the electrical power collector of the secondary battery which requires a long life.

1 is a view for explaining a method of measuring the strength (frequency) in the embodiment of the present invention.
2 is a view for explaining a method for measuring the large diameter crystallized average diameter in the embodiment of the present invention.

First, as one embodiment of this invention, the aluminum alloy foil for electrical power collectors is 0.3 mass% or more and 3.0 mass% or less of iron, 0.8 mass% or more and 1.5 mass% or less of silicon, 0.0001 mass% or more and 0.011 mass% or less Copper, 0.0001 mass% or more and 0.6 mass% or less, manganese, 0.0001 mass% or more and 0.011 mass% or less, zinc, 0.001 mass% or more and 0.011 mass% or less, and remainder contain aluminum and an unavoidable impurity. .

The reason for containing 0.3 mass% or more and 3.0 mass% or less of iron (Fe) in the aluminum alloy foil for electrical power collectors is as follows. Iron is an element which can crystallize out as an Al-Fe type compound in an aluminum alloy, and can improve the rolling property and elongation of an aluminum alloy foil. In addition, an appropriate amount of Al-Fe-based compound refines crystal grains by crystal nucleation sites and pinning, and results in baking resistance (welding of materials to a roll) and fine powder during rolling of aluminum alloy foil. By suppressing the occurrence of this, the rolling property of the thin foil is improved. When the content of iron is less than 0.3% by mass, the above effects cannot be sufficiently exhibited. If the iron content exceeds 3.0% by mass, the Al-Fe-based compound is excessively crystallized, so that the fracture strength of the aluminum alloy foil is reduced, or the tensile strength is excessively increased, and rather, the elongation and rollability of the aluminum alloy foil are deteriorated. There is.

The reason for including 0.8 mass% or more and 1.5 mass% or less of silicon (Si) in the aluminum alloy foil for electrical power collectors is as follows. Silicon is an element which can mainly improve the tensile strength of aluminum alloy foil. In addition, for example, when rolling to thin foil with a thickness of 15 micrometers or less, the instantaneous temperature rise accompanying a rolling process arises not only in the surface of an aluminum alloy foil but also inside. At this time, the presence of silicon in the aluminum alloy foil can suppress the dissipation of dislocations and prevent a decrease in strength. Said effect cannot be acquired when content of silicone is less than 0.8 mass%. When content of silicone exceeds 1.5 mass%, tensile strength will increase too much and the elongation and rollability of an aluminum alloy foil will fall.

The reason for limiting the quantity of copper (Cu) contained in the aluminum alloy foil for electrical power collectors to 0.011 mass% or less is as follows. Copper is easily dissolved in aluminum, reduces the elongation of the aluminum alloy foil, and increases the electrical resistivity. Moreover, copper significantly reduces the corrosion resistance of aluminum alloy foil. For this reason, it is necessary to limit content of copper to 0.011 mass% or less. More preferable content of copper is 0.005 mass% or less. Although the lower limit of content of copper is not specifically limited, Usually, it is about 0.0001 mass%.

The reason for limiting the amount of manganese (Mn) contained in the aluminum alloy foil for electrical power collectors to 0.6 mass% or less is as follows. Manganese is an element which can improve tensile strength and elongation, without reducing the corrosion resistance of aluminum alloy foil. However, due to excessive crystallization of Al-Mn-based compounds in the aluminum alloy, the fracture strength of the aluminum alloy foil is reduced, or the tensile strength is excessively increased, rather, the elongation and the rollability of the aluminum alloy foil may be deteriorated. , Increase the electrical resistivity. For this reason, it is necessary to limit content of manganese to 0.6 mass% or less. Although the minimum of content of manganese is not specifically limited, Usually, it is about 0.0001 mass%.

The reason for limiting the quantity of magnesium (Mg) contained in the aluminum alloy foil for electrical power collectors to 0.011 mass% or less is as follows. Magnesium is easily dissolved in aluminum, reduces the elongation of the aluminum alloy foil, and increases the electrical resistivity. For this reason, it is necessary to limit content of magnesium to 0.011 mass% or less. More preferable content of magnesium is 0.005 mass% or less. Although the lower limit of content of magnesium is not specifically limited, Usually, it is about 0.0001 mass%.

The reason for limiting the quantity of zinc (Zn) contained in the aluminum alloy foil for electrical power collectors to 0.3 mass% or less is as follows. Zinc contributes to the tensile strength and elongation of the aluminum alloy foil, but increases the electrical resistivity. In addition, zinc significantly lowers the corrosion resistance of the aluminum alloy foil. For this reason, it is necessary to limit content of zinc to 0.3 mass% or less. More preferable content of zinc is 0.1 mass% or less. Although the lower limit of content of zinc is not specifically limited, Usually, it is about 0.001 mass%.

Moreover, as one preferable embodiment of this invention, the aluminum alloy foil for electrical power collectors contains 0.005 mass% or more and 0.5 mass% or less titanium and / or 0.0001 mass% or more and 0.3 mass% or less zirconium.

The reason for including 0.005 mass% or more and 0.5 mass% or less of titanium (Ti) in the aluminum alloy foil for electrical power collectors is as follows. Titanium is an element capable of improving tensile strength and elongation without lowering the corrosion resistance of aluminum alloy foil. If the content of titanium is less than 0.005% by mass, the above effects cannot be obtained. When content of titanium exceeds 0.5 mass%, the tensile strength of aluminum alloy foil will increase too much and the rolling property of aluminum alloy foil will fall, and elongation will also fall.

The reason for including 0.0001 mass% or more and 0.3 mass% or less zirconium (Zr) in the aluminum alloy foil for electrical power collectors is as follows. Zirconium is an element which can improve tensile strength and elongation, without reducing the corrosion resistance of aluminum alloy foil. If the content of zirconium is less than 0.0001 mass%, sufficient tensile strength and elongation cannot be obtained. When content of zirconium exceeds 0.3 mass%, the tensile strength of aluminum alloy foil will increase too much and the rolling property of aluminum alloy foil will fall.

In addition, the aluminum alloy foil of the present invention is silver (Ag), nickel (Ni), chromium (Cr), vanadium (V), boron (B), gallium (Ga) in a content that does not affect the above characteristics and effects. ) And bismuth (Bi) may be included. In particular, when the content of silver and nickel is made 0.01% by mass or less, the corrosion resistance of the aluminum alloy can be prevented from being lowered.

As mentioned above, since the aluminum alloy foil for electrical power collectors of this invention has a limited composition, corrosion resistance does not fall compared with pure aluminum foil, and the electrical resistivity value is comparatively low, and it prevents excessive heat generation at the time of charge discharge. can do.

Next, in the aluminum alloy foil for electrical power collectors of this invention, the average diameter of the large diameter crystallization substance which exists in an aluminum alloy foil is 10 micrometers or less. As described above, since the average diameter of the large diameter crystallized substance present in the aluminum alloy foil is limited to a relatively small value, the fracture strength, that is, the bending strength of the aluminum alloy foil can be increased. Thereby, even if the thickness of an aluminum alloy foil is 15 micrometers or less, for example, it can prevent that an aluminum alloy foil breaks at the manufacturing process of the electrode which is accompanied by the process of bending the aluminum alloy foil for electrical power collectors in a vortex shape etc. . Here, the average diameter of a large diameter crystallized substance means the average value of the diameter of the crystallized substance measured by selecting predetermined number of crystallized substances in order from which the diameter of a crystallized substance is large among the crystallized substance which exists in aluminum alloy foil.

The average diameter of a large diameter crystallized substance is 10 micrometers or less, Preferably it is 5 micrometers or less, It is more preferable that it is 2/3 or less of thin thickness. Although the lower limit of the average diameter of a large diameter crystallized substance is not specifically limited, Usually, it is about 0.005 micrometer.

As mentioned above, since the aluminum alloy foil for electrical power collectors of this invention has a limited composition, and the average diameter of the large diameter crystallization substance which exists in aluminum alloy foil is limited to a relatively small value, it is excellent in tensile strength and abrasion resistance. Thereby, even if the thickness of an aluminum alloy foil is 15 micrometers or less, it can prevent breaking at the manufacturing process of an electrode. In addition, the aluminum alloy foil for current collectors of the present invention having a limited composition as described above does not have lower corrosion resistance compared to pure aluminum foil, and has a relatively low electrical resistivity value. In this case, excessive heat generation during charging and discharging can be prevented. By these, the aluminum alloy foil for electrical power collectors of this invention can be used for the electrical power collector of the secondary battery which requires a long life.

Moreover, as one preferable embodiment of this invention, the aluminum alloy foil for collectors is 15 micrometers or less in thickness, tensile strength is 170N / mm <2> or more, 280N / mm <2> or less, elongation 4% or more, fracture strength 350 times or more, The electrical resistivity value is less than 3. 7 μΩcm.

Process of apply | coating various active materials to the surface of 15 micrometers or less foil, when the tensile strength of an aluminum alloy foil does not satisfy | fill conditions of 170N / mm <2> or more, 280N / mm <2>, elongation 4% or more, and breaking strength 350 times or more. There exists a possibility that a foil may be broken in the manufacturing process of electrodes, such as the process of crimping | bonding the apply | coated active material to the surface of foil. In addition, when the electrical resistivity becomes 3.7 µΩcm or more, the current collector may generate heat during charging and discharging.

The lower limit of the thickness of the aluminum alloy foil is not particularly limited as long as the mechanical strength as the electrode can be maintained, but is usually about 1 μm.

The tensile strength of aluminum alloy foil is 170N / mm <2> or more and 280N / mm <2> or less, Preferably they are 190N / mm <2> or more and 280N / mm <2> or less. If the tensile strength of the aluminum alloy foil is less than 170 N / mm 2, there is a risk that the foil breaks in a step of producing an electrode such as a step of applying various active materials to the surface of the foil and a step of pressing the applied active material onto the surface of the foil. Moreover, when the tensile strength of aluminum alloy foil exceeds 280 N / mm <2>, there exists a possibility that rolling property of foil may be reduced.

The elongation of aluminum alloy foil is 4% or more, Preferably they are 4% or more and 10% or less. When the elongation of the aluminum alloy foil is less than 4%, there is a fear that the foil breaks in a step of producing an electrode such as a step of applying various active materials to the surface of the foil and a step of pressing the applied active material onto the surface of the foil. When the elongation of an aluminum alloy foil exceeds 10%, it will become difficult to make uniform the thickness of the active material to apply | coat.

The fracture strength of an aluminum alloy foil is 350 times or more, Preferably it is 450 or more times. If the strength of the aluminum alloy foil is less than 350 times, there is a risk that the foil breaks in a step of producing an electrode such as a step of applying various active materials to the surface of the foil and a step of pressing the applied active material onto the surface of the foil. Although the upper limit of the breaking strength of aluminum alloy foil is not specifically limited, Usually, it is about 1200 times.

The lower limit of the electrical resistance value of the aluminum alloy foil is not particularly limited, but is usually about 2.7 μΩcm.

The manufacturing method of the aluminum alloy foil for electrical power collectors of this invention which has the composition and characteristics as mentioned above casts the molten aluminum alloy which has the said composition by thickness of 3 mm or more and 10 mm or less with the cooling rate of 100 degree-C / sec or more. Thereby, the process of obtaining the ingot of an aluminum alloy and the process of rolling this ingot are provided.

Specifically, a molten aluminum alloy having the composition described above is prepared, and the molten aluminum alloy is solidified at a cooling rate of 100 ° C./sec or more, for example, by continuous casting to ingot having a thickness of 3 mm or more and 10 mm or less. To prepare. Then, it rolls by foil of a desired thickness by cold-rolling a ingot. Moreover, in the process after casting, for example, between the casting process and the rolling process, or after a rolling process, the heat processing (homogenization) for 1 minute or more and 100 hours or less at the temperature of 150 degreeC-about 650 degreeC as needed. Treatment). That is, when manufacturing the ingot of a thin aluminum alloy by continuous casting, after performing the said homogenization process to the ingot obtained by continuous casting, you may make it foil of a desired thickness by performing cold rolling, and by continuous casting It is good also as foil of desired thickness by performing cold rolling directly on the obtained ingot.

In the manufacturing method of the aluminum alloy foil for electrical power collectors of this invention, after crystallization is formed at the time of casting, it grind | pulverizes and thins by rolling. The size of the crystallized substance in aluminum alloy foil whose thickness is 15 micrometers or less can be controlled by casting and rolling.

When molten aluminum alloy is cast at a cooling rate later than 100 ° C / sec, coarse crystals of compounds such as Al-Fe and Al-Mn are formed, which makes it difficult to roll to a thickness of 15 µm or less. There exists a possibility that the average diameter of the large diameter crystallized substance which exists in the aluminum alloy foil for electrical power collectors may increase, and abrasion resistance may fall. More preferable cooling rate is 150 degree-C / sec or more. Although the upper limit of a cooling rate is not specifically limited, Usually, it is about 500 degree-C / sec.

Casting thickness is 3 mm or more and 10 mm or less, Preferably they are 3 mm or more and 6 mm or less. If the casting thickness is thicker than 10 mm, it is difficult to obtain a desired cooling rate inside the ingot. Moreover, when casting thickness is thinner than 3 mm, there exists a possibility that the crystallization formed at the time of casting may not fully grind | pulverize by rolling.

(Example)

Hereinafter, embodiments of the present invention will be described.

Preparation of the molten aluminum alloy (A-U) of various compositions shown in Table 1 (alloys (A-K) have a composition within the scope of the present invention, alloys (L-T) have a composition outside the scope of the present invention) And the ingot of Examples 1-11 and Comparative Examples 1-21 was manufactured by solidifying the molten aluminum alloy so that it might become the casting thickness shown in Table 2. In Examples 1-11 and Tables 12-21 shown in Table 2, the molten metal was cast by the continuous casting method, and in Comparative Examples 1-11, the molten metal was cast by inject | pouring into a fixed mold. After casting, each ingot was divided into three by approximately three lengths along the casting direction, and both ends were processed as follows by using the sample as a sample for measuring the cooling rate during casting described later.

As shown in Table 2, ingots with a casting thickness of more than 10 mm were subjected to a homogenization treatment at a temperature of 520 ° C. for 5 hours, and then rolled to a thickness of 6 mm by hot rolling, and further 12 탆 by cold rolling. The aluminum alloy foil for electrical power collectors was produced by rolling to the thickness of. The cast ingot having a casting thickness of 10 mm or less was subjected to homogenization treatment at a temperature of 400 ° C. for 1 hour, and then rolled to a thickness of 12 μm by cold rolling to produce an aluminum alloy foil for current collectors.

The obtained aluminum alloy foils for current collectors of Examples 1 to 11 and Comparative Examples 1 to 21 were subjected to various properties (large diameter crystallized average diameter, tensile strength, elongation, fracture resistance, rolling resistance, corrosion resistance, electrical resistivity values). Evaluated. The evaluated characteristic is shown in Table 2.

In addition, 1N30, 8021, 8079, and 3003 aluminum alloys of JIS nominally used as current collector foils for lithium ion batteries are produced in the same manner as above, and aluminum alloy foils for current collectors (conventional examples 1 to 4) are produced and evaluated. Carried out. The evaluation results are also shown in Table 2.

Here, the evaluation of "corrosion resistance" is 1 mol / liter of LiPF ₆ in a non-aqueous electrolyte solution in which the aluminum alloy foil for each current collector is mixed with a lithium ion battery electrolyte solution (diethylene carbonate and ethylene carbonate in a ratio of 1: 1 by volume ratio). It was immersed at room temperature for 30 days) and observed by visually observing the degree of corrosion. "Corrosion resistance" was evaluated by making x into those which hardly corrode and signs of corrosion, such as pitting corrosion. In addition, "rolling property" evaluated that what was able to manufacture continuously without breaking to thickness of 6 micrometers as (circle) and the thing which was not broken or rolled during rolling was made into x. In addition, the "electric resistivity value" of each aluminum alloy foil for electrical power collectors was measured by the DC 4-terminal method at the temperature of 293K.

"Tensile strength (N / mm 2)" and "elongation (%)" were evaluated as follows. About each aluminum alloy foil for electrical power collectors, the tensile test was done with the tensile tester according to JIS B 7721, and tensile strength and elongation were calculated | required as follows. A 10 mm wide, 150 mm long sample was fixed so that the distance between the chucks was 50 mm, and ten tensile tests were conducted at a tensile speed of 10 mm / min to measure tensile strength and elongation. . 0.2% elongation was made into "elongation", the tensile strength at break was made into "tensile strength", and the average value was calculated | required.

"Sustained intensity (frequency)" was evaluated as follows. For each current collector aluminum alloy foil, 200 gf load was applied to a sample having a width of 15 mm and a length of 150 mm using a MIT type automatic bending test apparatus according to JIS P8115, and the bending radius R was zero. A bending test was performed at a repetition speed of 5 mm and bending at 360 times / second. As shown in FIG. 1, the sample 100 is bent 90 degrees once as indicated by arrow 1, and returned twice to the original as shown by arrow 2, and bent 90 degrees in the reverse direction as shown by arrow 3 three times. As shown in Fig. 4, the number of times of bending was returned to the original and counted until the sample 100 broke. "Steel strength (number of times)" in Table 2 represents the number of bends when each sample breaks.

"Large diameter crystallized average diameter (micrometer)" was evaluated as follows. A 10 mm wide sample was embedded in the epoxy resin so that the LT-ST plane (cross section perpendicular to the rolling direction) became the observation plane, and the observation plane was buff polished (diamond polishing), and then the scanning electron microscope (SEM) observed. In the photograph of 20 field of view (magnification 500 times) photographed at random, as shown in FIG. 2, the diameter (D) of the crystallized substance having a large ratio with respect to the thickness (T) is 40 as shown in FIG. 2. Dog measured. "Large diameter crystallographic average diameter (micrometer)" of Table 2 shows the average value of the top 30 values among the obtained measured values.

"Casting rate at casting (° C / sec)" was evaluated as follows. Samples of two ingots (both ends) were embedded in an epoxy resin so that the LT-ST plane (cross section perpendicular to the rolling direction) became the observation plane, and the observation plane was buff polished (diamond polishing), followed by a scanning electron microscope ( SEM). In the photograph of 20 viewing field (1000 times magnification) which photographed the surface layer part and the center part of each sample randomly, the secondary dendrite spacing d (micrometer) was measured, and the The average value of the measured values was calculated | required. The cooling rate (C) at the time of solidification (degreeC / sec) was computed by substituting the average value (d) (micrometer) of this secondary dendritic crystal spacing into the following Formula, and it was set as "cooling rate at the time of casting (degreeC / sec)."

d = bC- ⁿ

Here, b is 33 and n is 0. 33.

alloy
Composition (mass%) Fe Si Cu Mn Mg Zn Ti Zr A 0.5 0.9 0.01 0.5 0.0001 0.25 0.1 0.12 B 1.0 0.9 0. 05 0.2 0.0001 0.002 0.012 0.02 C 1.5 0.9 0.0005 0.07 0.0001 0.09 0.01 0.0006 D 2.0 1.0 0.001 0.005 0.0005 0.002 0.01 0.001 E 2.5 1.2 0.001 0.005 0.0005 0.002 0.02 0.001 F 2.9 0.9 0.001 0.005 0.0005 0.002 0.02 0.001 G 2.5 1.1 0.0006 0.005 0.0005 0.0017 0.011 0.01 H 2.0 1.4 0.001 0.0025 0.0001 0.0017 0.01 0.0001 I 1.2 0.8 0.001 0.005 0.0005 0.002 0.02 0.25 J 1.5 1.2 0.0005 0.002 0.0001 0.002 0.01 0.002 K 1.5 1.0 0.001 0.005 0.0005 0.002 0.4 0.002 L 0.2 0.5 0.001 0.005 0.0005 0.002 0.02 0.12 M 3.1 0.5 0.001 0.005 0.0005 0.002 0.02 0.15 N 2.0 0.5 0.001 0.005 0.0005 0.002 0.02 0.4 O 1.0 0.6 0.001 0.005 0.0005 0.002 0.02 0.1 P 1.0 1.7 0.001 0.005 0.0005 0.002 0.02 0.1 Q 1.5 0.5 0.001 0.005 0.0005 0.002 0.6 0.1 R 1.5 0.5 0.02 0.005 0.0005 0.002 0.01 0.12 S 1.5 0.5 0.001 0.005 0.0005 0.4 0.01 0.12 T 1.5 0.5 0.001 0.005 0.02 0.002 0.01 0.12 U 1.1 0.5 0.001 0.7 0.005 0.02 0.01 0.001 1N30 0.4 0.3 0.08 0.05 0.05 0.04 - 0.05 8021 1.5 0.1 0.05 &Lt; 0.1 <0.01 - - <0.01 8079 1.0 0.3 0.04 &Lt; 0.1 <0.01 0.01 - <0.01 3003 0.6 - 0.1 1.1 <0.01 0.1 - <0.01

alloy Cooling rate during casting
(° C / sec) Casting thickness
(Mm) Large diameter crystallized average diameter
(탆) The tensile strength
(N / mm2) Height
(%) Seismic strength
(Count) Rollability Corrosion resistance Electrical resistivity
(μΩcm) Example
One A 110 9 3.2 204 4.5 505 ○ ○ 3.40 Example 2 B 124 5 3.3 214 4.1 621 ○ ○ 3.30 Example 3 C 161 5 3.1 260 4.8 945 ○ ○ 3.60 Example 4 D 158 5 3.8 250 4.6 832 ○ ○ 3.24 Example 5 E 155 5 4.1 259 5.0 750 ○ ○ 3.50 Example 6 F 153 5 4.7 260 4.0 695 ○ ○ 3.55 Example 7 G 173 5 4.1 266 4.8 560 ○ ○ 3.22 Example 8 H 162 5 4.6 265 4.1 490 ○ ○ 3.41 Example 9 I 165 5 3.4 268 5.0 830 ○ ○ 3.52 Example 10 J 182 5 3.1 250 5.2 960 ○ ○ 3.10 Example 11 K 177 5 3.2 260 4.6 850 ○ ○ 3.44 Comparative Example 1 A 12 30 13 180 3.0 150 ○ ○ 3.39 Comparative Example 2 B 13 30 14 183 2.8 160 ○ ○ 3.20 Comparative Example 3 C 14 30 16 199 3.2 230 ○ ○ 3.40 Comparative Example 4 D 42 9 18 187 3.1 190 ○ ○ 3.20 Comparative Example 5 E 12 30 19 201 3.9 140 ○ ○ 3.48 Comparative Example 6 F 11 30 21 210 2.8 180 ○ ○ 3.50 Comparative Example 7 G 12 30 18 198 2.7 143 ○ ○ 3.04 Comparative Example 8 H 38 9 19 189 2.6 130 ○ ○ 3.12 Comparative Example 9 I 13 30 15 201 3.8 200 ○ ○ 3.20 Comparative Example 10 J 14 30 18 200 3.9 225 ○ ○ 3.08 Comparative Example 11 K 12 30 17 210 3.2 221 ○ ○ 3.21 Comparative Example 12 L 148 5 3.2 160 2.0 501 ○ ○ 3.01 Comparative Example 13 M 152 5 4.3 285 2.5 480 × ○ 3.71 Comparative Example 14 N 159 5 4.0 290 3.0 600 × ○ 3.40 Comparative Example 15 O 146 5 3.5 170 1.8 530 ○ ○ 3.05 Comparative Example 16 P 163 5 5.2 290 2.0 450 × ○ 3.04 Comparative Example 17 Q 179 5 3.3 290 2.0 505 × ○ 3.49 Comparative Example 18 R 161 5 3.2 245 2.2 539 ○ × 3.55 Comparative Example 19 S 154 5 3.3 232 1.8 534 ○ × 3.51 Comparative Example 20 T 112 5 3.1 241 1.5 350 ○ ○ 3.60 Comparative Example 21 U 120 5 3.3 230 2.9 260 ○ ○ 4.20 Conventional Example 1 1N30 15 30 12 160 1.8 169 ○ × 2.90 Conventional Example 2 8021 10 30 16 180 1.6 140 ○ × 3.07 Conventional Example 3 8079 12 30 14 160 1.7 122 ○ × 3.07 Conventional Example 4 3003 15 30 11 265 1.0 290 ○ ○ 4.10

As can be seen from Table 2, in Examples 1 to 11 of the present invention, the elongation is 4% or more, the tensile strength is 170N / mm 2 or more and 280N / mm 2 without lowering the corrosion resistance, and the electrical resistivity value is 3. Aluminum alloy foil whose thickness is less than 7 ohm-cm and whose thickness is 12 micrometers of 350 times or more of breaking strength is obtained.

The embodiments and examples disclosed above are to be considered in all respects only as illustrative and not restrictive. The scope of the present invention is not the above-described embodiments and examples, but is indicated by the claims, and is intended to include all modifications and variations within the meaning and range equivalent to the claims.

Industrial availability

The aluminum alloy foil for electrical power collectors of this invention is used as a material for forming the electrical power collector for positive electrodes of secondary batteries, such as a lithium ion battery, for example.

100: sample

Claims (5)

0.3 mass% or more and 3.0 mass% or less iron, 0.8 mass% or more and 1.5 mass% or less silicon, 0.0001 mass% or more and 0.011 mass% or less copper, 0.0001 mass% or more and 0.6 mass% or less manganese, and 0.0001 mass % To 0.011 mass% magnesium, 0.001 mass% to 0.011 mass% zinc, 0.005 mass% to 0.5 mass% titanium, 0.0001 mass% to 0.3 mass% zirconium. An aluminum alloy foil for current collectors composed of aluminum and unavoidable impurities,
The average diameter of the large diameter crystallized substance which exists in this aluminum alloy foil is 0.005 micrometer or more and 10 micrometers or less
Aluminum alloy foil for current collectors.
delete delete The method of claim 1,
Thickness is 1 micrometer or more and 15 micrometers or less, tensile strength 170N / mm <2> or more 280N / mm <2> or less, elongation 4% or more and 10% or less, fracture strength 350 times or more and 1200 times or less, electrical resistivity value 2.7 microohm cm or more 3.7 less than μΩcm
Aluminum alloy foil for current collectors.
As a manufacturing method of the aluminum alloy foil for electrical power collectors of Claim 1,
A process of obtaining an ingot of an aluminum alloy by casting the molten aluminum alloy at a thickness of 3 mm or more and 10 mm or less at a cooling rate of 100 ° C / sec or more and 500 ° C / sec or less,
With the step of rolling the ingot
The manufacturing method of the aluminum alloy foil for electrical power collectors.

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