Electrolytic copper foil for secondary battery, having enhanced flexural resistance, and method for producing same
The present invention relates to an electrolytic copper foil for a secondary battery, having excellent flexural resistance, and a method for producing the electrolytic copper foil. The electrolytic copper foil for a secondary battery has excellent flexural resistance even without the use of many additives in a copper electrolyte when producing a copper foil. The electrolytic copper foil for a secondary battery according to the present invention is an electrolytic copper foil for a secondary battery, which is produced from a plating solution, containing total organic carbon (TOC), cobalt and arsenic, by using a drum and is coated with a negative electrode active material, wherein the ratio between the TOC, cobalt and arsenic contained in the electrolytic copper foil follows the following formula 1: TOC/(cobalt+arsenic)=1.30-1.55. [Formula 1]
1. A method for producing an electrolytic copper foil for a secondary battery, the method comprising:
(1) preparing a plating solution containing copper, total organic carbon (TOC), metal additives that contain cobalt and arsenic; and
(2) performing electrolytic-plating of the plating solution using a drum at a temperature of 30° C. to 70° C. by applying a current at a current density 30 ASD to 150 ASD to the drum, thereby to form an electrolytic copper foil,
wherein a ratio of the TOC to the cobalt and the arsenic contained in the electrolytic copper foil satisfies a following Equation 1:
TOC content/(cobalt content+arsenic content)=1.30 to 1.55. [Equation 1]
2. The method of claim 1 , wherein each of a tensile strength and an elongation at −30° C. of the electrolytic copper foil is maintained to be greater than or equal to 80% of each of a tensile strength and an elongation at a room temperature of the electrolytic copper foil.
3. The method of claim 1 , wherein a concentration of the TOC contained in the plating solution is 100 ppm or greater.
4. The method foil of claim 1 , wherein the electrolytic copper foil formed by the electrolytic-plating in (2) has one face in direct contact with the drum and the other face opposite to said one face, wherein a Rz roughness of each of said one and other faces is smaller than or equal to 2.0 μm.
5. The method of claim 1 , wherein a tensile strength of the electrolytic copper foil is in a range of 30 kgf/mm 2 to 51 kgf/mm 2 .
6. The method of claim 1 , wherein an elongation of the electrolytic copper foil is in a range of 2% to 15%.
7. The method of claim 1 , wherein a thickness of the electrolytic copper foil is in a range of 4 μm to 10 μm.
8. A method for producing a secondary battery comprising:
producing the electrolytic copper foil according to the method of claim 1 ; and
coating a negative electrode active material with the electrolytic copper foil.