Electrolytic copper foil for secondary battery and method for producing the same
The present invention relates to an electrolytic copper foil for a secondary battery and a method of producing the same. The electrolytic copper foil for a secondary battery, in which a burr and curl of a negative electrode plate are inhibited from being formed after an electrolytic copper foil is coated with a negative electrode active material, thereby increasing the loading volume of a negative electrode and increasing a capacity. The electrolytic copper foil for a secondary battery is produced from a plating solution containing Total Organic Carbon (TOC) by using a drum, in which the electrolytic copper foil is formed of one surface that is in direct contact with the drum and the other surface that is an opposite surface of the one surface, and an average cross-sectional grain size of the one surface is 80% or less of an average cross-sectional grain size of the other surface.
1. An electrolytic copper foil for a secondary battery produced from a plating solution containing Total Organic Carbon (TOC) by using a drum,
wherein the electrolytic copper foil is formed of one surface that is in direct contact with the drum and an other surface that is an opposite surface of the one surface,
wherein the electrolytic copper foil is pressed at a pressure of 4 MPa or higher after being coated with a negative electrode active material, and an average cross-sectional grain size of the electrolytic copper foil before the electrolytic copper foil is pressed is 0.5 μm to 1 μm or less, and the average cross-sectional grain size of the electrolytic copper foil after the electrolytic copper foil is pressed is 90% or more of the average cross-sectional grain size of the electrolytic copper foil before the electrolytic copper foil is pressed, and
wherein a concentration of the TOC contained in the plating solution is equal to or larger than 100 ppm.
2. The electrolytic copper foil of claim 1 , wherein an average cross-sectional grain size of the electrolytic copper foil after the electrolytic copper foil is pressed at the pressure of 4 MPa or higher is 0.45 μm to 0.9 μm.
3. The electrolytic copper foil of claim 1 , wherein tensile strength of the electrolytic copper foil is 30 kgf/mm 2 to 50 kgf/mm 2 .
4. The electrolytic copper foil of claim 1 , wherein an elongation percentage of the electrolytic copper foil is 2% to 12%.
5. The electrolytic copper foil of claim 1 , wherein a thickness of the electrolytic copper foil is 2 μm to 10 μm.