KR20180038690A - Elctrodeposited copper foil, current collectors for secondary batteries and secondary batteries - Google Patents

Abstract

An electrolytic copper foil for a lithium secondary battery according to the present invention, which is applied to a cathode current collector of a lithium secondary battery, is characterized by having a high temperature hardness value which is a hardness value of the electrolytic copper foil measured after one hour of heat treatment at 190 deg. C and which shows a reduction rate in a range of 10-30% in comparison with a room temperature hardness value, which is a hardness value of electrolytic copper foil measured without heat treatment.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a current collector and a secondary battery including an electrolytic copper foil and an electrolytic copper foil,

The present invention relates to an electrolytic copper foil excellent in high-temperature adhesive force, a negative electrode current collector for a secondary battery comprising the electrolytic copper foil, and a secondary battery including the negative electrode current collector.

In the field of electronic devices, as the demand for portable devices has increased, the size and weight of the devices have been reduced. Therefore, development of a battery having a high energy density, particularly a secondary battery, is required. There is a lithium secondary battery as a candidate for the secondary battery satisfying this requirement. The lithium secondary battery has high voltage and high energy density and is light in weight as compared with the nickel cadmium battery, the lead battery, and the nickel metal hydride battery. Lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, or a composite oxide thereof is used as the positive electrode active material of the lithium secondary battery, and carbon materials such as graphite and amorphous carbon are used as the negative electrode active material. A metal foil is used as a current collector for drawing a current from these positive / negative electrode active materials and guiding the current to the battery terminals. Particularly, the copper foil is widely used as an anode current collector because it does not form a compound with lithium, has good electrical conductivity, and is low in cost. The copper foil has a rolled copper foil produced by rolling and an electrolytic copper foil produced by electrolytic deposition. The rolled copper foil is disadvantageous in that its bonding strength with the active material is weak because of its high strength and smooth surface. For this reason, when the charge / discharge cycle is repeated, the active material is peeled off at the interface between the copper foil and the copper foil to reduce the charge / discharge capacity and shorten cycle life. In addition, since the surface of the electrolytic copper foil is somewhat coarse, the state of adhesion with the active material is good but the strength is weak, causing disadvantages such as cracking due to charging and discharging, which causes reduction in charge / discharge capacity and deterioration in cycle life.

The electrolytic copper foil is usually produced by a stripping apparatus as shown in Fig. 1, in which a rotating drum-like cathode 12 (made of SUS or titanium) and an anode 11 (zinc or noble metal And an electric current is flowed between the positive and negative electrodes while flowing the electrolytic solution 13 to deposit copper on the surface of the cathode to a predetermined thickness and thereafter peeling the copper from the surface of the cathode in the form of a metal foil. The copper foil 14 at this stage is an untreated copper foil. The surface of the untreated copper foil in contact with the electrolyte is a matte side and the surface in contact with the rotating drum-shaped cathode 12 is a shiny side.

Since the deposition surface (matte surface) of the conventional electrolytic copper foil is a columnar crystal structure and the surface roughness of the electrolytic copper foil deposition surface is rough, the contact area with the negative electrode active material such as carbon powder is small, the contact resistance is large, and the charge / discharge cycle life is short And the surface roughness of the electrolytic copper foil precipitation surface is made to be as small as that of the rolled copper foil has been developed and used as a lithium ion secondary battery.

Japanese Patent Application Laid-open No. 7-188969 (Patent Document 1), Japanese Patent Application Laid-Open No. 8-53789 (Patent Document 2), Japanese Patent Application Laid-Open No. 2000-182623 (Japanese Patent Laid- Patent Document 3) There is an electrolytic copper foil disclosed in the publication. The characteristics of the electrolytic copper foil disclosed in these patent documents are such that the surface roughness of the electrolytic copper foil precipitation surface is reduced by controlling various additives, electrolyte composition, electrolyte temperature, electrolyte flow rate, current density and the like.

Although the electrolytic copper foil disclosed in the above Patent Documents is superior to the rolled copper foil so far, it is not sufficient for the market demand in terms of the charge / discharge cycle life and overcharging characteristics. In particular, in the case of a high capacity secondary battery, The amount of loading of the negative electrode active material in the negative electrode current collector (the amount of slurry coated per unit area of the electrolytic copper foil) is steadily increasing. Thus, it is necessary to further increase the adhesive force between the negative electrode current collector and the slurry.

Patent Document 1: JP-A-7-188969 Patent Document 2: JP-A-8-53789 Patent Document 3: Japanese Patent Application Laid-Open No. 2000-182623

Conventionally, the surface roughness of the electrolytic copper foil is intentionally lowered to maintain the adhesion between the electrolytic copper foil as the current collector and the slurry as the negative active material. However, management of the surface roughness of the electrolytic copper foil has a limitation in increasing the adhesion force required by the high capacity secondary battery.

Therefore, one object of the present invention is to find and control the physical property factors for enhancing the adhesion between the electrolytic copper foil used as the negative electrode collector of the high capacity secondary battery and the negative electrode active material slurry.

For this purpose, the present inventors paid attention to the surface hardness of the electrolytic copper foil in order to enhance the adhesion between the electrolytic copper foil used as the anode current collector of the high capacity secondary battery and the anode active material slurry. That is, it was confirmed that excellent high-temperature adhesive force between the anode current collector and the anode active material slurry of the high capacity secondary battery was realized by adjusting the hardness value of the electrolytic copper foil to a constant numerical value range.

The technical problem to be solved by the present invention is not limited to the above-mentioned problems, and other technical problems not mentioned above can be clearly understood by those skilled in the art from the description of the invention described below.

According to an aspect of the present invention, there is provided an electrolytic copper foil for a lithium secondary battery, which is applied to an anode current collector of a lithium secondary battery according to an embodiment of the present invention, has a high temperature hardness value And a reduction rate in the range of 10% to 30% as compared with the value of normal temperature which is the hardness value of the electrolytic copper foil measured at room temperature without the heat treatment.

An electrolytic copper foil according to another aspect of the present invention comprises 0.1 to 5 ppm of an inorganic metal as an additive, 0.01 to 0.5 ppm of an anionic additive, 0.01 to 5 ppm of an anionic additive, (Cu) was electrodeposited on the surface of the drum of the pre-charging machine at a temperature of 40 to 70 캜 and a current density of 10 ASD to 80 ASD, in which an electrolyte solution containing 0.1 to 0.5 ppm of a leveler and 0.1 to 0.5 ppm of a brightener was added, And a high temperature hardness value, which is the hardness value of the electrolytic copper foil measured after the heat treatment at 190 ° C. for 1 hour, shows a reduction ratio in the range of 10% to 30% as compared with the hardness value of the electrolytic copper foil measured at room temperature without heat treatment .

At this time, the room temperature hardness value is preferably 1.35 GPa or more, and the high temperature hardness value is preferably 1.0 to 1.3 GPa or less. The surface roughness of both surfaces of the electrolytic copper foil is 0.3 탆 to 1.5 탆 on the basis of Rz. It is preferable that the electrolytic copper foil has a protective layer containing at least one of chromium (Cr), silane coupling agent and BTA (benzotriazole) on both surfaces.

According to another aspect of the present invention, an anode current collector for a secondary battery is characterized in that an anode active material is coated on at least one surface of an electrolytic copper foil according to one aspect of the present invention. In another embodiment of the present invention, the secondary battery negative electrode current collector is applied to a negative electrode.

The high temperature hardness value, which is the hardness value of the electrolytic copper foil measured after the heat treatment at 190 캜 for one hour according to another embodiment of the present invention, is 10% to 30% lower than the room temperature hardness value, which is the hardness value of the electrolytic copper foil measured at room temperature, (A) 0.1 to 5 ppm of an inorganic metal additive as an additive in an aqueous copper sulfate solution having a copper concentration of 60 g / L to 90 g / L and a sulfuric acid concentration of 70 g / L to 120 g / L, 0.01 to 0.5 ppm of an anionic additive, 0.1 to 0.5 ppm of a leveler and 0.1 to 0.5 ppm of a brightener to prepare an electrolytic solution; And (b) electrodepositing copper (Cu) on the surface of the drum of the pre-charging machine at an electrolytic temperature of 40 to 70 ° C and a current density of 10 ASD to 80 ASD.

Wherein the inorganic metal additive includes at least one of Fe, W, Zn, Mo, and Co, and the anion additive includes at least one of Cl, F, Br, I, and PO4, and the leveler includes gelatin, collagen, PEG (polyethylene glycol), wherein the brightener is selected from the group consisting of bis (3-sulfopropyl) disulfide, MPS (mercapto-propane sulphonic acid), 3-N, N-dimethylaminodithiocarbamoyl-1-propanesulphonic acid ), And the like. .

According to the present invention, an electrolytic copper foil having excellent physical properties in terms of prevention of wrinkle formation can be obtained, and when the electrolytic copper foil is applied to an anode current collector, adhesion strength between the anode current collector and the anode active material is remarkably improved.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further the understanding of the technical idea of the invention. And should not be construed as limiting.
1 is a cross-sectional view of a washer device for electrodeposition an electrolytic copper foil according to an embodiment of the present invention.
2 is a cross-sectional view of an untreated copper foil produced by the stripping apparatus of Fig.
3 is a cross-sectional view illustrating a state in which a protective layer is coated on the surface of an electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention.
4 is an apparatus for evaluating the occurrence of wrinkles at room temperature of an electrolytic copper foil according to an embodiment of the present invention.
5 is a cross-sectional view showing a state in which an electrolytic copper foil is adhered on a slide glass in order to measure a high-temperature adhesive force of an electrolytic copper foil according to an embodiment of the present invention.
6 is a cross-sectional view showing a state in which a high-temperature adhesive force of an electrolytic copper foil adhered on a slide glass is measured using a UTM equipment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

First, an electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention will be described with reference to FIG. 2 is a cross-sectional view illustrating an electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention.

The electrolytic copper foil 1 for a lithium secondary battery according to an embodiment of the present invention shown in FIG. 2 is preferably used as an anode current collector of a lithium secondary battery. That is, in the lithium secondary battery, an electrolytic copper foil is preferably used as the negative electrode current collector to be combined with the negative electrode active material.

On the other hand, in the production of a lithium secondary battery, a foil made of aluminum (Al) is generally used as a positive electrode collector combined with a positive electrode active material.

Accordingly, in the present invention, the electrolytic copper foil 1 for a lithium secondary battery corresponds to an anode current collector applied to a lithium secondary battery.

The electrolytic copper foil 1 for a lithium secondary battery according to an embodiment of the present invention is obtained by heat treating the electrolytic copper foil 1 for a lithium secondary battery at 190 占 폚 for 1 hour against a hardness value (hereinafter abbreviated as "room temperature hardness value" Hardness value (hereinafter abbreviated as "high temperature hardness value") is 10% or more and 30% or less. As described above, the high temperature hardness value of the electrolytic copper foil used as the anode current collector of the lithium secondary battery should be decreased by 10% or less than 30% of the room temperature hardness value. When the high temperature hardness value for the room temperature hardness value changes, This is because the adhesion between the current collector and the electrolytic copper foil is optimized. Especially, when the high temperature hardness value is changed by more than 30% than the normal temperature hardness value, it may be difficult to control the physical properties of the electrolytic copper foil.

It is preferable that the room temperature hardness value is 1.35 GPa or more because if the hardness of the electrolytic copper foil is low, there is a high possibility of wrinkling in the roll-to-roll process for coating the negative electrode active material. If wrinkles occur in the electrolytic copper foil, coating of the negative electrode active material on the surface of the negative electrode current collector, which is an electrolytic copper foil, may not be uniformly performed, resulting in variations in coating thickness and appearance of the negative electrode active material. However, the above-mentioned room temperature hardness value generally does not exceed 3GPa.

It is preferable that the high temperature hardness value is 1.0 GPa to 1.3 GPa. If the high temperature hardness value is less than 1.0 GPa, burr may occur during the punching operation in the battery assembling process. If it exceeds 1.3 GPa, The adhesion between the whole and the slurry of the active material may be reduced, resulting in defective manufacturing of the battery.

On the other hand, the surface roughness of both surfaces 1a and 1b (the mat surface and the shiny surface) of the electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention is about 0.3 to 1.5 m on the basis of Rz (ten point average roughness) desirable.

If the surface roughness is less than about 0.3 탆, the adhesion between the electrolytic copper foil and the active material is deteriorated. If the adhesion between the electrolytic copper foil and the active material deteriorates, the risk of the active material detachment during the use of the lithium secondary battery increases .

On the contrary, when the surface roughness is more than about 1.5 탆, the active material can not be uniformly coated on the surface of the electrolytic copper foil due to high roughness, resulting in a decrease in adhesion. If the active material is not uniformly coated The discharge capacity retention rate of the produced lithium secondary battery may be lowered.

3, the electrolytic copper foil 1 for a lithium secondary battery according to an embodiment of the present invention may have a protective layer 2 formed on the surfaces 1a and 1b.

The protective layer 2 is selectively formed on the surfaces 1a and 1b of the electrolytic copper foil for protecting the surface of the electrolytic copper foil 1 for a lithium secondary battery and is selected from among chromium (Cr), silane coupling agent and BTA (benzotriazole) And any one or more of them.

The negative electrode active material is coated on at least one surface of the electrolytic copper foil of FIG. 3 according to an embodiment of the present invention to manufacture a negative electrode current collector for a lithium secondary battery, and the negative electrode current collector is applied to a negative electrode to manufacture a lithium secondary battery .

< Example  And Comparative Example >

Hereinafter, the characteristics of the present invention will be more clearly understood by preparing electrolytic copper foils of Examples satisfying the characteristics of the present invention and comparative examples thereof, and comparing the physical properties between electrolytic copper foils of this and comparative examples.

The electrolytic copper foil for a lithium secondary battery according to Examples and Comparative Examples was produced by using a negative electrode foil as shown in Fig. 1 in a structure including a rotating drum and a positive electrode plate positioned at a predetermined interval with respect to the drum in an electrolytic bath. At this time, the gap between the positive electrode plate and the rotary drum is adjustable in the range of about 5 to 20 mm, and the standard deviation of the gap should be controlled within 2 mm.

The electrolytic solution used in the stamping process using such a magma forming process may be copper sulfate, and a copper foil is electrodeposited on the drum by using an inorganic metal additive, an anion additive, a leveler, a brightener, .

The inorganic metal additive may include 0.1 to 5 ppm of at least one of Fe, W, Zn, Mo, and Co, and the copper sulfate electrolyte may include 60 to 90 g / L of copper and 70 to 120 g / 0.01 to 0.5 ppm of at least one of Cl, F, Br, I and PO ₄ is added as an anionic additive and 0.1 to 0.5 ppm of gelatin, collagen and PEG (polyethylene glycol) is added as a leveler, Brightner is added by 0.1 to 0.5 ppm of at least one of bis (3-sulfopropyl) disulfide (SPS), mercapto-propane sulphonic acid (MPS) and 3-N, N-dimethylaminodithiocarbamoyl-1-propanesulphonic acid. An electrolytic copper foil for a lithium secondary battery according to an embodiment of the present invention is manufactured by preparing an electrolytic copper foil under such conditions that the current density is in the range of 10 ASD to 80 ASD and the electrolytic solution temperature is 40 to 70 캜.

On the other hand, in order to produce an electrolytic copper foil for a lithium secondary battery corresponding to a comparative example, a method different from the manufacturing method of the above-described embodiment is applied. Specifically, copper sulfate (60 to 90 g / L copper , 70 to 120 g / L of sulfuric acid) are prepared as shown in Table 1 below to prepare an electrolytic copper foil to produce an electrolytic copper foil for a lithium secondary battery according to a comparative example.

The composition and condition of a specific electrolytic solution for pretreating electrolytic copper foil according to Examples and Comparative Examples are as follows.

Copper: 60 ~ 90g / L

Sulfuric acid: 70 to 120 g / L

Electrolyte temperature: 55 ° C

Current density: 60 ASD

Inorganic additive: Co

Anion additive: PO ₄

Leveler: PEG

Brightner: SPS

Current density: 60ASD , Electrolyte temperature: 55 캜 Cu (g / L) H2SO4 (g / L) Co  PO ₄ PEG SPS Example  One 85 75 3.4 0.01 0.2 0.1 Example  2 87 90 0.5 0.1 0.2 0.5 Example  3 85 85 0.6 0.1 0.1 0.2 Example  4 86 77 3.2 0.05 0.5 0.3 Example  5 85 78 0.5 0.2 0.5 0.3 Example  6 89 83 3.1 0.1 0.5 0.5 Comparative Example  One 88 87 0 13 2 20 Comparative Example  2 85 78 0 18 2 6 Comparative Example  3 85 76 0 0 2 6 Comparative Example  4 75 80 7 0.2 0.2 0.1 Comparative Example  5 75 80 10 0.2 0.2 0.5

The electrolytic copper foil according to the examples and the comparative examples shown in the above Table 1 were subjected to an electrolytic copper plating treatment at a room temperature hardness, a high temperature hardness (a hardness obtained in a state of being heat treated at 190 캜 for one hour) and a reduction rate of a high temperature hardness value Table 2 shows the difference in the effect of physical properties.

An electric boat  Performance evaluation

1) At room temperature hardness measurement

Measuring equipment Model: agilent Technologies / Nano indenter G200

      Surface Approach Velocity (nm / s): 10 nm / s

      Depth Limit (nm): 1000 nm

      Strain Rate Target (1 / S): 0.05

2) High temperature hardness measurement

After heat treatment at 190 캜 for 1 hour, the hardness is measured in the same manner as in the above-mentioned "1) Measurement of room temperature hardness ".

3) Evaluation of wrinkle occurrence at room temperature

As shown in FIG. 4, the angle between the No. 1 roll 20 and the No. 2 roll 30 is adjusted to 1.5 ° to artificially cause misalignment, Whether or not wrinkles are generated in the electrolytic copper foil of Examples is determined and described in Table 2 below.

2) High-temperature adhesive force measurement

(1) Preparation of Specimen: An anode active material slurry was prepared by mixing carbon and additives such as CMC (Carboxy Methyl Cellulose) and SBR (Styrene-butadiene rubber) in a ratio of 97: 1: 2, The slurry was coated on the electrolytic copper foil of the comparative example and dried, followed by roll pressing to prepare specimens for each of Examples and Comparative Examples. At this time, the electrode density of the cathode is 1.5 g / cm 3.

2) High-Temperature Adhesive Force Measurement: The thus-prepared specimen 40 was heat-treated at 190 DEG C for 1 hour or more, cut into 200 mm in width and 100 mm in length, and then the double-sided tape 50 (trade name: Nitto Denso 5605) And is then stuck on the slide glass 60. [ Thereafter, as shown in Fig. 6, a high-temperature adhesive force was measured using a UTM instrument at a load cell of 10 N and a measurement speed of 100 mm / min. If the high temperature adhesive force is 20 N / m or more, the separation between the anode current collector and the active material does not occur during charging and discharging of the battery, and when the charging / discharging time is less than 20 N / m, Can not be maintained.

Room temperature hardness
[ GPa ] High temperature hardness
[ GPa ] Reduction rate of high temperature hardness to room temperature hardness [%] Wrinkle
[O, X] Adhesion
[N / m] Example  One 1.53 1.15 24.8 Wrinkles × 26 Example  2 1.40 1.00 28.6 Wrinkles × 27 Example  3 1.45 1.22 15.9 Wrinkles × 26 Example  4 1.50 1.14 24.0 Wrinkles × 25 Example  5 1.47 1.30 11.6 Wrinkles × 24 Example  6 1.40 1.21 13.6 Wrinkles × 24 Comparative Example  One 1.34 1.33 0.75 Wrinkles ○ 22 Comparative Example  2 1.52 1.49 1.97 Wrinkles × 18 Comparative Example  3 1.52 1.44 5.3 Wrinkles × 19 Comparative Example  4 1.52 1.04 31.6 Wrinkles × 16 Comparative Example  5 1.54 1.02 33.8 Wrinkles × 15

Referring to Table 2, in all of Examples 1 to 6, not only the proper room temperature hardness value and the high temperature hardness value are maintained, but the reduction rate of the high temperature hardness value to the room temperature hardness value is maintained at 10% to 30% Wrinkles are not generated at room temperature, and the high temperature adhesive force is 20 N / m or more, so that dropout between the anode current collector and the active material does not occur.

However, in Comparative Example 1, wrinkles were generated in the roll-to-roll process of the electrolytic copper foil because both the room temperature hardness value, the high temperature hardness value and the reduction ratio of the high temperature hardness value to the room temperature hardness value deviate from the numerical range of the present invention.

In Comparative Examples 2 to 3, although the value of the room temperature hardness is appropriate, the value of the high temperature hardness does not greatly decrease with respect to the value of the room temperature hardness, so that wrinkles are not generated in the roll-to-roll process, but the high temperature adhesive force is less than 20 N / m Dropout between the negative electrode current collector and the active material may occur.

In Comparative Example 4 and Comparative Example 5, although the value of the room temperature hardness is appropriate, the value of the high temperature hardness is excessively decreased with respect to the value of the room temperature hardness, so that wrinkles are not generated in the roll- The dropout between the current collector and the active material may occur.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

1: electrolytic dip for lithium secondary battery
1a, 1b: copper foil surface
2: Protective layer

Claims (15)

1. An electrolytic copper foil for a lithium secondary battery, which is applied to an anode current collector of a lithium secondary battery,
And a high temperature hardness value which is a hardness value of the electrolytic copper foil measured after the heat treatment at 190 캜 for 1 hour shows a reduction ratio in the range of 10% to 30% as compared with a room temperature hardness value which is a hardness value of the electrolytic copper foil measured at room temperature without heat treatment An electric boat. The method according to claim 1,
Wherein the normal temperature hardness value is 1.35 GPa or more. 3. The method of claim 2,
Wherein the high temperature hardness value is 1.0 to 1.3 GPa or less. The method of claim 3,
Wherein the surface roughness of both surfaces of the electrolytic copper foil is 0.3 탆 to 1.5 탆 on the basis of Rz. 5. The method of claim 4,
Wherein the electrolytic copper foil has a protective layer containing at least one of chromium (Cr), a silane coupling agent, and BTA (benzotriazole) on both surfaces thereof. The secondary battery negative electrode collector according to any one of claims 1 to 5, wherein at least one surface of the electrolytic copper foil is coated with a negative electrode active material. The secondary battery according to claim 6, wherein the secondary battery negative electrode current collector is applied to the negative electrode. 0.1 to 5 ppm of an inorganic metal, 0.01 to 0.5 ppm of an anionic additive, 0.1 to 0.5 ppm of a leveler and 0.1 to 0.5 ppm of a brightener are added to an aqueous solution of copper sulfate having a copper concentration of 60 g / L to 90 g / L and a sulfuric acid concentration of 70 g / L to 120 g / in an electrolytic copper foil produced by electrodepositing copper (Cu) on the surface of a drum of a non-magnetic forming machine at a temperature of 40 占 폚 to 70 占 폚 and a current density of 10 ASD to 80 ASD,
And a high temperature hardness value which is a hardness value of the electrolytic copper foil measured after the heat treatment at 190 캜 for 1 hour shows a reduction ratio in the range of 10% to 30% as compared with a room temperature hardness value which is a hardness value of the electrolytic copper foil measured at room temperature without heat treatment An electric boat. 9. The method of claim 8,
Wherein the normal temperature hardness value is 1.35 GPa or more. 10. The method of claim 9,
Wherein the high temperature hardness value is 1.0 to 1.3 GPa or less. The electrolytic copper foil having a reduction ratio in the range of 10% to 30% as compared with the room temperature hardness value, which is the hardness value of the electrolytic copper foil measured at room temperature without heat treatment, after the heat treatment at 190 占 폚 for 1 hour. As a method,
(a) 0.1 to 5 ppm of an inorganic metal additive, 0.01 to 0.5 ppm of an anionic additive, 0.1 to 0.5 ppm of an anionic additive, and 0.1 to 5 ppm of an inorganic additive as additives, in an aqueous copper sulfate solution having a copper concentration of 60 to 90 g / L and a sulfuric acid concentration of 70 to 120 g / Adding 0.1 to 0.5 ppm of brightener to prepare an electrolytic solution; And
(b) electrodepositing copper (Cu) on the surface of the drum of the pre-charging machine at an electrolytic temperature of the electrolytic solution of 40 ° C to 70 ° C and a current density of 10 ASD to 80 ASD. Way. 12. The method of claim 11,
Wherein the inorganic metal additive comprises at least one of Fe, W, Zn, Mo, and Co. 12. The method of claim 11,
Wherein the anionic additive comprises at least one of Cl, F, Br, I, and PO4. 12. The method of claim 11,
Wherein the leveler comprises at least one of gelatin, collagen, and polyethylene glycol (PEG). 12. The method of claim 11,
Wherein the brightener comprises at least one of bis (3-sulfopropyl) disulfide (SPS), mercapto-propane sulphonic acid (MPS) and 3-N, N-dimethylaminodithiocarbamoyl-1-propanesulphonic acid A method of manufacturing a copper foil.

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