KR102088882B1 - Rolled copper foil for lithium ion secondary battery current collector - Google Patents

Abstract

(Task) Provided is a rolled copper foil for a lithium ion secondary battery current collector that is stable and efficient and has improved adhesion to resin.
(Solution) The rolled copper foil for lithium ion secondary battery current collectors is mainly composed of Cu, Cr, Ｚr, sn, mv, ア ｇ, Ｆe, コ, ニ, Ｚn, テ ィ, Si, Ｂ, Ｂｉ, ｂ, The copper crystal composition obtained by X-ray diffraction 2θ / θ measurement, having a copper alloy composition containing 0.1% by weight to 0.5% by weight, and inevitable impurities, in a total amount of one or more elements selected from the group of elements consisting of Mn The ratio of the diffraction peak intensity I [220] in the direction of 220} Cu and the diffraction peak intensity I [200] in the direction of {200} Cu is I [220] / I [200]> 2.1.

Description

Rolled copper foil for current collectors for lithium ion secondary batteries {ROLLED COPPER FOIL FOR LITHIUM ION SECONDARY BATTERY CURRENT COLLECTOR}

The present invention relates to a rolled copper foil for a lithium ion secondary battery current collector having a resin adhesion property suitable for a current collector of a lithium ion secondary battery.

Lithium ion secondary batteries are used as batteries for electronic devices such as mobile PCs and portable terminals because high voltage is obtained and energy density is high. In addition, research and development have been actively conducted as a driving battery for a hybrid vehicle or an electric vehicle.

In such a lithium ion secondary battery, charging and discharging is repeated by moving lithium electrodes in an electrolyte between a positive electrode plate and a negative electrode plate insulated by a separator. It is based on structure. It is important to find materials for electrolytes, separators, positive and negative plates that can realize this structure at high cycle characteristics.

Examples of the negative electrode plate used for a lithium ion secondary battery include a negative electrode current collector made of a copper foil or a copper alloy foil (hereinafter sometimes referred to simply as "copper foil"), and a negative electrode active material layer formed on the current collector. It is generally composed of. The copper foil constituting the negative electrode current collector is made of metal from a rolled copper foil produced by performing rolling processing on a thick annealed copper wire produced by casting, or an electrolytic solution containing copper ions. Electrolytic copper foil manufactured by electrolytically converting copper is used. This rolled copper foil has a feature that the copper crystal structure of the copper foil can be controlled by combining rolling processing and heat treatment.

The negative electrode active material layer formed on the surface of the copper foil is formed to a thickness of about 100 μm. This negative electrode active material layer contains carbon particles such as artificial graphite, natural graphite or coke with N-methyl2- together with a binder such as polyvinylidene fluoride and a conductive aid. It is obtained by mixing with a solvent such as pyrrolidone (NMP) to form a slurry, and then applying it to the surface of a copper foil to dry and solidify.

In a lithium ion secondary battery, when charging / discharging is repeated, carbon is easily peeled from the copper foil due to expansion / contraction of carbon particles following the insertion / discharge of lithium, causing short circuit between electrodes, deterioration of battery capacity, deterioration of cycle characteristics, etc. There is a risk of causing. For this reason, as the copper foil for a negative electrode current collector, high adhesion to carbon constituting the negative electrode active material layer is required. Adhesion with carbon can be improved to some extent by increasing the proportion of the binder in the slurry, but it is not an effective means because the conductivity of the electrode decreases.

Therefore, in order to solve this problem, it has been made to perform a roughening treatment to form irregularities on the surface of the copper foil. As a method of this roughening treatment, methods such as blast treatment, rolling by rough roll, mechanical polishing, electropolishing, chemical polishing, and plating of electrodeposition particles are known, Among these, plating of electrodeposition particles is particularly used.

However, the non-uniform and highly roughened particles, on the contrary, have a weak anchor effect, so that high adhesion between the negative electrode current collector and the negative electrode active material is not obtained. Therefore, in order to have a complex structure on the surface of the copper foil with roughened particles of low roughness, a method of performing plural plating treatments or reflow treatments has been taken (for example, patents). Reference 1).

Patent Document 1: Japanese Patent Application Publication No. 2009-87561

However, since the method described in Patent Document 1 is expensive, it leads to high price of lithium ion secondary batteries, which hinders the general supply of lithium ion secondary batteries to electronic devices, electric vehicles, and the like.

An object of the present invention is to provide a rolled copper foil for a lithium ion secondary battery current collector that is stable and efficient and has improved adhesion to resin.

The inventors of the present application and the like have repeatedly studied in order to achieve the above object. In the case of a rolled copper foil, if a certain correlation is used between the direction / orientation state of the grains of the rolled surface and the resin adhesion of the copper foil, for example, the surface of the copper foil On the other hand, it was found that the resin adhesion of the copper foil was increased without performing a roughening treatment such as plating of electrodeposited particles, and it was found that an unexpected product can be obtained and an excellent product that does not cause problems in practical use can be formed.

[1] That is, the present invention is composed mainly of Cu, and is selected from the group of elements consisting of Cr, Mur, Sn, Mg, Ab, Ze, Co, Ni, Gi, Ti, Si, Si, Si, Si and Si. Diffraction peak strength in the {220} Cu direction of copper crystals obtained by X-ray diffraction 2θ / θ measurement, having a copper alloy composition containing 0.1% by weight to 0.5% by weight of one or more added elements and inevitable impurities It is a rolled copper foil for lithium ion secondary battery current collectors, characterized in that the ratio of the diffraction peak intensity I [200] in the direction of [220] and {200} Cu is I [220] / I [200]> 2.1.

[2] The invention described in the above [1], comprising at least one additive element selected from Cr, Mur, Sn, Ab or Ti from among the above element groups, and at least one added element of these elements. The amount of addition,

Cr of 0.10 to 0.4% by weight,

0.01 to 0.2% by weight of Ｚr,

0.12 to 0.2% by weight of Sn,

0.1 to 0.2% by weight of Aｇ or

0.05 to 0.2% by weight Ti

It is characterized by satisfying any one of them.

[3] The invention described in the above [1], which does not contain any of elements of Cr, Mur, Sn, Ab, and Ti in the element group, and includes Mb, Hee, Co, Ni, Ni, Si, and Si. , Si, Si, and Mn, and further comprises 0.2% by weight or more of the total amount of Mg, Hee, Co, Ni, Si, Si, Si, Si, and Sn.

[4] The invention of any one of [1] to [3] above, wherein {220} Cu of copper crystals obtained by X-ray diffraction 2θ / θ measurement after heating for 1 to 20 hours at a temperature of 200 degrees or less. It is characterized in that the ratio of the diffraction peak intensity I [220] in the direction and the diffraction peak intensity I [200] in the {200} Cu direction is I [220] / I [200]> 2.1.

[5] The invention described in the above [4], characterized in that it realizes a peel strength of 60.9 (N / m) or more and a conductivity of 77% or more.

[6] The invention according to any one of [1] to [5], wherein the rolled copper foil for a lithium ion secondary battery current collector has a thickness of 20 μm or less.

ADVANTAGE OF THE INVENTION According to this invention, the rolled copper foil for lithium ion secondary battery electrical power collectors which has good adhesiveness with resin and is realized stably and efficiently is obtained.

1 is a flow chart showing the flow of a manufacturing process of a copper foil for a lithium ion secondary battery current collector according to a preferred embodiment of the present invention.
Fig. 2 is a schematic diagram showing the relationship between incident X-rays, a detector, a sample, and a scanning axis in X-ray diffraction.
Fig. 3 is a diagram schematically showing the atomic arrangement of the rolled surface when the {200} Cu plane is oriented.
4 is a diagram schematically showing the atomic arrangement of the rolled surface when the {220} Cu plane is oriented.
Fig. 5 is a diagram schematically showing an example of the production procedure of the peel test piece.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Components of rolled copper foil)

The rolled copper foil in this embodiment is suitably used as a material for a lithium ion secondary battery current collector. In this rolled copper foil, Cu (copper) was used as the mother phase, and Cr (chromium), Ｚr (zirconium), Sn (tin), Mb (magnesium), Ab (silver), Ｆe (iron), and Co ( 1 selected from the group of elements consisting of cobalt), Ni (nickel), 티 n (zinc), Ti (titanium), Si (silicon), Ｂ (boron), Si (bismuth), Sｂ (antimony), and Mn (manganese) The basic composition is composed of a component composed of more than one type of additive element and the remainder consisting of inevitable impurities. As Cu, tough pitch copper or oxygen-free copper can be used.

(More desirable upper limit of additive elements)

It is preferable that the total amount of one or more additive elements selected from the group consisting of Cr, Mur, Sn, Mg, Ab, Ze, Co, Ni, Gi, Ti, Si, Si, Si, Si and Mn is 0.5% by weight or less. Do. Even if the total amount of these added elements is added more than 0.5% by weight, there is no effect of further improving the heat resistance. In the case of high heat resistance, even in the state after being heated for 1 to 20 hours at a temperature of 200 degrees or less after the final cold rolling process, the orientation in the {200} Cu direction is unlikely to occur, so the diffraction intensity ratio I [220] / I [200]> 2.1 relationship is satisfied. In addition, since the resistance increases when more than 0.5% by weight is added, there is a concern that the characteristics of the lithium ion secondary battery such as the discharge rate characteristic of the lithium ion secondary battery manufactured using such copper foil may be deteriorated.

(More preferable lower limit of the additive element)

It is preferable to set the content of Cr, Mur, Sn, Ab, and Ti in these additive elements to 0.02% by weight or more in total amount. Sufficient heat resistance can be obtained by setting the content of these additive elements to 0.02% by weight or more.

In addition, in the contents of Mg, Fe, Co, Ni, Si, Si, Si, Si, Si and Mn, the total amount of the above-mentioned elements, Cr, Mur, Sn, Ab, and Ti, was set to 0.1% by weight or more. It is more preferable. This is because by increasing the amount of these added elements to more than 0.1% by weight, the heat resistance can be increased compared to the case where the total amount is 0.1% by weight or less.

On the other hand, when it does not contain Cr, Mur, Sn, Ab, and Ti, it is preferable to make the content of Mb, Fe, Co, Ni, Si, Si, Si, Si, Sb, and Mn 0.2% by weight or more. This is because the amount required to obtain heat resistance equivalent to Cr, Mur, Sn, Ab and Ti increases.

The thickness of the rolled copper foil is preferably 20 μm or less. The lithium ion secondary battery manufactured using a rolled copper foil having a thickness of more than 20 μm has a large volume fraction of the rolled copper foil. For this reason, in an environment where a high bulk energy density is required, there is a fear that the negative electrode current collector may not be sufficiently charged with the negative electrode active material.

(Method of manufacturing rolled copper foil)

Referring to Fig. 1, Fig. 1 shows a typical manufacturing process for manufacturing a rolled copper foil according to this embodiment. The process of manufacturing this rolled copper foil includes a solvent process, a hot rolling process, a cold rolling process, an intermediate annealing process, and a green annealing process. (生地 燒 鈍 工程), the final cold rolling process (finishing rolling process) and a series of processes of the cathode plate manufacturing process (steps (100 to 106), hereinafter, the step `` S ”. By carrying out the treatment in these steps in order, a desired rolled copper foil is effectively obtained.

(Solvent process)

In this solvent step, 1 selected from the group of elements consisting of Cu and 0.5 wt% or less of Cr, Mur, Sn, Mg, Ab, Hue, Co, Ni, Gi, Ti, Si, Si, Si, Si and Si. The ingot (ingot) which becomes a copper alloy material is manufactured by melt | dissolving the additive element of more than 1 type using a melting furnace (S (100) of FIG. 1).

(Hot rolling process)

In this hot rolling step, the ingot is hot rolled at a predetermined temperature to form a plate material (S101 in Fig. 1).

(Cold rolling process, intermediate annealing process and dough annealing process)

In this cold rolling step and the intermediate annealing step, intermediate annealing to moderate the work hardening by cold rolling and cold rolling is appropriately repeated on the plate material after hot rolling (S102) to S (103 in Fig. 1). )). In this way, dongjo, called "saengji", is produced. In this green annealing process (S104 in FIG. 1), it is preferable that the processing deformation before the green annealing process is sufficiently relaxed.

(Final cold rolling process)

In this final cold rolling process, a finish rolling process is performed on the annealed dough (S105 in Fig. 1). Thus, a rolled copper foil (finished copper foil) of a predetermined thickness is produced. It is preferable that the total workability is 85% or more and less than 95%. Accordingly, it is possible to reduce the total number of passes in the rolling process with respect to the rolled copper foil of the conventional high workability. In addition to this, it is possible to avoid the difficulty of controlling the rolling process due to excessive work hardening, and it can also contribute to the reduction of the load on the manufacturing equipment and the lower cost of manufacturing. It is possible to achieve both high resin adhesion and low cost in rolled copper foil.

(Cathode plate manufacturing process)

The rolled copper foil after the final cold rolling process does not perform roughening treatment by plating of electrodeposited particles or the like and manufactures the next negative electrode plate. A negative electrode active material layer is directly formed on the rolled copper foil. The negative electrode active material layer is, for example, a carbon system such as hard carbon or soft carbon, a graphite system such as artificial graphite or natural graphite, an oxide system such as lithium titanate, or an alloy such as Sn or Si composite material. A mixture in which particles containing a system are uniformly mixed in a resin binder is used.

At this time, the resin binder before coating is generally a solvent-based binder containing a solvent such as n-methylpyrrolidone (NMP) for the purpose of lowering the viscosity from the viewpoint of uniformity of mixing or coating properties of a rolled copper foil. Used, but not limited to this. In addition, an aqueous binder may be used, for example, for the purpose of suppressing deterioration of operability due to the use of a solvent and reducing environmental load. If uniform mixing and application of the resin binder is possible, a resin binder containing no solvent or water may be used.

When the resin binder contains a solvent or water, the current collector is prepared by applying a resin binder and drying it by heat treatment.

As the resin binder, various kinds of resin binders, such as polyvinylidene fluoride (PFD), fluorine-based resin, polyacrylate, styrene-butadiene rubber (SBR), or polyimide, are resins having properties such as desired heat resistance, mechanical strength, or chemical stability. Can be used. In this manufacturing process of the negative electrode plate, for example, in the drying process after the application of the negative electrode active material or the drying process after assembly of the lithium ion secondary battery, heat treatment of 100 to 200 degrees is performed (S (106) in FIG. 1).

In the method of manufacturing the rolled copper foil, {220 of copper crystals obtained by X-ray diffraction 2θ / θ measurement in a state heated for 1 minute to 20 hours at a temperature of 200 degrees or less immediately after or after the final cold rolling process The ratio between the diffraction peak intensity I [220] in the Cu direction and the diffraction peak intensity I [200] in the {200} Cu direction (hereinafter also referred to as “diffraction intensity ratio”) is I [220] / I [200]> It is important to control to have a 2.1 person relationship. Here, I [220] and I [200] are X-ray diffraction strengths of the {220} crystal plane and the {200} crystal plane on the rolling surface of the rolled copper foil.

In the final cold rolling process, by performing cold rolling with a high workability of 85% or more and less than 95%, the orientation of the {220} Cu surface is strong and {200} on the rolling surface of the copper foil in the state immediately after the final cold rolling process. } As the orientation of the Cu plane is weak, the upper limit of the diffraction intensity ratio is not particularly limited, but the relationship of the diffraction intensity ratio I [220] / I [200]> 2.1 is satisfied. More preferably, it is preferable to satisfy the relationship of the diffraction intensity ratio I [220] / I [200]> 5. This orientation can be determined by an X-ray diffraction method such as the θ-2θ method.

Referring to Fig. 2, Fig. 2 shows the relationship between the incident X-rays, the detector, the sample, and the scanning axis in X-ray diffraction. In the X-ray diffraction apparatus, the θ axis is generally called a sample axis. The measurement of scanning the sample 1 and the detector 2 with respect to the incident X-rays on the θ axis, scanning the scanning angle of the sample 1 with θ and scanning angle of the detector 2 with 2θ is called 2θ / θ measurement. do. Based on the intensity of the diffraction peaks measured by the 2θ / θ measurement, it is possible to evaluate which crystal surface is predominant on the sample surface (rolled surface) of a rolled copper foil that is a polycrystalline material. In addition, since the crystal structure of copper is cubic, the angle between the {200} Cu plane and the {220} Cu plane is 45 degrees. Here, "{}" represents an equivalent plane.

As described above, the rolled copper foil is one or more additive elements selected from the group of elements consisting of Cr, Ｚr, Sn, Mb, Ab, Fe, Co, Ni, Si, Si, Si, Si, Si, Si and Mn. By adding 0.5% by weight or less of the total amount, heat resistance is improved. Therefore, even in the state after being heated for 1 minute to 20 hours at a temperature of 200 degrees or less after the final cold rolling process, orientation in the {200} Cu direction is unlikely to occur, and the diffraction intensity ratio I [220] / I [200]> The 2.1 person relationship is satisfied.

In the final cold rolling process, by obtaining a stronger orientation in the direction of the rolling aggregate {220} Cu, rolling is performed even after heating for 1 to 20 hours at a temperature of 200 degrees or less immediately after or after the final cold rolling process. Orientation in the {200} Cu direction is unlikely to occur on the surface, whereby a rolled copper foil having good resin adhesion properties is stably obtained.

(Consideration on the mechanism of high resin adhesion)

In the rolled copper foil, the state of the atomic arrangement on the surface of the copper foil varies depending on the direction / orientation state of the grains on the rolled surface, and the interatomic distance on the surface of the copper foil changes. In the {220} Cu plane, atoms are arranged at a distance closest to a certain direction and a direction perpendicular to it, as shown in FIG. On the other hand, in the {200} Cu plane, atoms are arranged at a distance between the closest to a certain direction and a distance between the next proximity to a direction perpendicular to the direction, as shown in FIG. 4.

It is considered that the resin applied to the surface of the copper foil solidifies on the surface of the copper foil in a stable state determined by the interatomic force between the atoms of the copper foil surface and the atoms constituting the resin and the intermolecular forces between the resins.

Therefore, the stability of the stable state of the resin solidified on the surface of the copper foil can be further improved by well matching the specific atomic structure of the copper foil surface with the specific periodic molecular structure of the organic resin. It is thought that it leads to improving resin adhesiveness.

[Example]

Hereinafter, examples and comparative examples will be described in detail as more specific embodiments of the present invention. In this embodiment, a typical example of the rolled copper foil as the above embodiment is given, but it goes without saying that the present invention is not limited to these examples and comparative examples.

The rolled copper foils of Examples 1 to 25 and the rolled copper foils of Comparative Examples 1 to 4 were prepared without roughening such as plating of electrodeposited particles, and compared and evaluated. The composition of the rolled copper foils in Examples 1 to 25 and Comparative Examples 1 to 4, the heat treatment conditions after the final cold rolling, the X-ray diffraction strength ratio I [220] / I [200], peel strength, and the results of the checkerboard test It is collectively shown in Table 1 below.

As a method for evaluating the adhesion, the rolled copper foils of Examples 1 to 25 and the rolled copper foils of Comparative Examples 1 to 4 were coated with a typical polyvinylidene fluoride (PＶdＦ) as a resin solvent for the binder, dried, and then dried on the surface of the copper foil. The dried and solidified (hereinafter referred to as "binder-coated copper foil") was subjected to a peel test and a checkerboard test.

(Production of rolled copper foil)

The copper alloy of the alloy component shown in Table 1 was melted using oxygen-free copper as a base material and cast into an ingot. After the hot rolling was performed on the ingot, the cold rolling and the annealing of the dough were sequentially performed, and then the final cold rolling was performed with a high workability of 85% or more and less than 95%. Thus, Examples 1 to 25 and Comparative Examples 1 to 4, which were rolled copper foils having a thickness of 10 μm, were obtained.

(X-ray diffraction for rolled copper foil)

An X-ray diffraction apparatus (manufactured by Rigaa, type ＵｌｔｉｍａＩＶ) was used to measure X-ray diffraction 2θ / θ on the rolled surface of the rolled copper foil. Table 1 summarizes the measurement results.

(Peel test)

Fig. 5 schematically shows an example of the production procedure of the peel test piece. The copper foil 4 (binder-coated copper foil) coated with the binder film 3 was cut into a rectangle having a width of 12.5 mm and a length of 80 mm, and a rectangular binder-coated copper foil was adhered to the reinforcing plate 5. The strong adhesive force tape 6 is attached to about half the length of the rectangle of the copper foil coated with a binder. By pulling the strong adhesive force tape 6, a part of the binder film 3 was removed from the copper foil coated with a binder to obtain a peel test piece. Then, the peel strength of the peeled portion was measured by holding the binder film 3 together with the strong adhesive tape 6 with the chuck of the peel tester and raising the speed when lifting in the vertical direction at 5 mm / min. Table 1 summarizes the measurement results.

(Checkerboard test)

The rolled copper foils of Examples 1 to 25 and the rolled copper foils of Comparative Examples 1 to 4 were produced as test pieces, one by one. Using 100 pieces of each test piece, 25 pieces (1mm square) were made on the binder film 3 of the copper foil coated with a binder by using a cutter in accordance with the BIS8602, and a cellophane tape was adhered to the binder film 3 After the adhesion, the binder film 3 was peeled off, and the adhesiveness was evaluated by the number of eyes of the checkerboard that were not peeled off. Here, those that did not peel off even one piece were marked with ○, those with only 1 to 5 pieces peeled off with Δ, and those peeled off with 6 or more pieces were evaluated with ×. Table 1 summarizes the evaluation results.

From the results shown in Table 1, Examples 1 to 25 are selected from the group of elements consisting of Cr, Mur, Sn, Mb, Ab, Ze, Co, Ni, Si, Si, Si, Si, Si, Si and Mn. The diffraction intensity ratio in the state of heating for 1 minute to 20 hours at a temperature of 200 degrees or less immediately after or after the final cold rolling step is set at 0.5% by weight or less with one or more added elements set to I [220] / I [ 200] By controlling to have a relationship of 2.1, it was found that the desired rolled copper foil can be stably obtained and good resin adhesion can be realized.

In particular, in Examples 1 to 7, it was possible to obtain a rolled copper foil having a peel strength of 59.7 (N / m) or more, a good checkered test result, and a conductivity of 77% or more. Likewise, when 0.10 to 0.4% by weight of Cr, 0.01 to 0.2% by weight of Cr, 0.12 to 0.2% by weight of Sn, 0.1 to 0.2% by weight of Aｇ or 0.05 to 0.2% by weight of Ti are satisfied , It was found that the results of the high peel strength and the checkerboard test were good.

On the other hand, as in Comparative Examples 1 and 2, when the additive element such as Cr is not contained, even after being heated for 1 to 20 hours at a temperature of 200 degrees or less after the final cold rolling process, {200} Cu Since the orientation in the direction occurs, the relationship between the diffraction intensity ratios I [220] / I [200]> 2.1 cannot be satisfied. As a result, it can be understood that in Comparative Examples 1 and 2, the peel strength was lower than in Examples 1 to 25 and it was difficult to realize good resin adhesion.

Also, as in Comparative Examples 3 and 4, even if the added elements such as Cr are contained within the specified range, if the heat treatment conditions after the final cold rolling process deviate from the intended target, the diffraction intensity ratio is I [220]. / I [200]> 2.1 cannot be satisfied. As a result, it can be understood that in Comparative Examples 3 and 4, the peel strength was lower than in Examples 1 to 25, and it was difficult to realize good resin adhesion.

Therefore, as in Comparative Examples 3 and 4, even if the content of the added element is within the specified range, if the conditions of the heat treatment temperature / time after the final cold rolling process are out of the intended target, the adhesion to the resin is good. It was found that the rolled copper foil was not obtained stably.

As described above, the rolled copper foil for a lithium ion secondary battery current collector of the present invention is a copper foil with good adhesion to a resin, and is said to have extremely effective effects in industry, such as contributing to prolonged life and safety of lithium ion batteries. It was proved.

As is apparent from the above description, a typical configuration example of the rolled copper foil for a lithium ion secondary battery current collector of the present invention has been described with reference to the embodiments, examples, and examples shown in the drawings. Examples and examples shown in the drawings are not intended to limit the invention with respect to the claims. It should be noted that not all combinations of features described in the above-described embodiments, examples, and examples shown in the drawings are necessary for solving the problems of the present invention, and various configurations are within the scope of the technical idea of the present invention. Of course it is possible.

One… sample
2… Detector
3… Binder film
4… Copper foil
5... Reinforcement
6... Strong adhesive tape

Claims (6)

The main component is Cu, and the total amount of one or more additive elements selected from the group of elements consisting of Cr, Ｚr, Sn, Mg, Aｇ, Ｆe, コ, Ni, Ｚn, Ti, Si, Ｂ, Ｂｉ, Sｂ, and Mn A copper alloy composition containing 0.1% by weight to 0.5% by weight and unavoidable impurities is provided,
The ratio of the diffraction peak intensity in the {220} Cu direction I [220] and the diffraction peak intensity in the {200} Cu direction I [200] of the copper crystal obtained by X-ray diffraction 2θ / θ measurement is I [220 ] / I [200]> 2.1 A rolled copper foil for a lithium ion secondary battery current collector.
According to claim 1,
Among the above-mentioned group of elements, at least one additive element selected from Cr, Mur, Sn, Ab or Ti is provided, and
The added amount of at least one element added to these elements,
Cr of 0.10 to 0.4% by weight,
0.01 to 0.2% by weight of Ｚr,
0.12 to 0.2% by weight of Sn,
0.1 to 0.2% by weight of Aｇ or
0.05 to 0.2% by weight Ti
A rolled copper foil for a lithium ion secondary battery current collector, characterized in that any one of them is satisfied.
According to claim 1,
The element group does not contain any elements of Cr, Ｚr, Sn, Aｇ, and Ti, and includes one or more of Mb, Ｆe, コ, Ni, Ｚn, Si, Ｂ, Ｂｉ, Sｂ, and Mn, Also
Rolled copper foil for a lithium ion secondary battery current collector, characterized in that it contains 0.2 wt% or more and 0.5 wt% or less of the total amount of Mg, Fe, Co, Ni, Si, Si, Si, Si, and Mn.
The method according to any one of claims 1 to 3,
After heating for 1 to 20 hours at a temperature of 200 degrees or less, the diffraction peaks in the {220} Cu direction diffraction peaks of the copper crystals obtained by X-ray diffraction 2θ / θ measurements I [220] and the diffraction peaks in the {200} Cu direction Rolled copper foil for a lithium ion secondary battery current collector, characterized in that the ratio of strength I [200] is I [220] / I [200]> 2.1.
According to claim 4,
A rolled copper foil for a lithium-ion secondary battery current collector, which is characterized by having a peel strength of 60.9 (N / m) or more and a conductivity of 77% or more.
The method according to any one of claims 1 to 3,
A rolled copper foil for a lithium ion secondary battery current collector, which has a thickness of 20 μm or less.

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