Electrolytic copper foil, electrode comprising the same, secondary battery comprising the same, and method for manufacturing the same
Disclosed are an electrolytic copper foil the fold and/or wrinkle of which can be avoided or minimized during a roll-to-roll process, a method for manufacturing the same, and an electrode and a secondary battery which are produced with such electrolytic copper foil so that high productivity can be guaranteed. An electrolytic copper foil of the disclosure has a longitudinal rising of 30 mm or less and a transverse rising of 25 mm or less, and the transverse rising is 8.5 times the longitudinal rising or less.
1. A method for manufacturing an electrolytic copper foil, the method comprising:
allowing a current to flow between an anode plate and a rotational cathode drum to form a copper film on the rotational cathode drum, the anode plate and the rotational cathode drum spaced apart from each other in an electrolytic solution contained in an electrolytic bath;
dipping the copper film in an anticorrosion solution; and
taking the copper film out of the anticorrosion solution,
wherein the copper film is guided by a guide roll disposed in the anticorrosion solution when the copper film is dipped in and taken out of the anticorrosion solution, and
wherein the method further comprises, after taking the copper film out of the anticorrosion solution, spraying an anticorrosion solution onto a surface of the copper film which was in contact with the guide roll during the dipping process.
2. The method according to claim 1 , wherein the anode plate comprises first and second plates electrically insulated from each other,
wherein the forming the copper film comprises forming a seed layer by allowing a current to flow between the first plate and the rotational cathode drum, and then growing the seed layer by allowing a current to flow between the second plate and the rotational cathode drum, and
wherein a current density provided by the first plate is 1.5 times or higher than a current density provided by the second plate.
3. The method according to claim 2 , wherein the anode plate further comprises a third plate between the first and second plates, and
a current density provided by the third plate is lower than the current density provided by the first plate and higher than the current density provided by the second plate.
4. The method according to claim 1 , wherein the current density provided by the anode plate is 40 to 70 A/dm 2 .
5. The method according to claim 1 , wherein the electrolytic solution comprises 50 to 100 g/L of a copper ion, 50 to 150 g/L of sulfuric acid, 50 ppm or less of a chlorine ion and an organic additive.
6. The method according to claim 5 , wherein the organic additive is gelatin, hydroxyethyl cellulose (HEC), organic sulfide, organic nitride, a thiourea compound, or a mixture of two or more thereof.
7. The method according to claim 1 , wherein the electrolytic solution is supplied into the electrolytic bath at a flow rate of 40 to 46 m 3 /hour when the copper film is formed.