EP3309881

[0001] Provided are an easily handleable electrolytic copper foil which secures a highly durable secondary battery, an electrode including the same, a secondary battery including the same, and a method of manufacturing the same. The electrolytic copper foil, which includes a first surface and a second surface opposite the first surface, includes a copper layer including a matte surface facing the first surface and a shiny surface facing the second surface, a first protective layer formed on the matte surface of the copper layer, and a second protective layer formed on the shiny surface of the copper layer, wherein a coefficient of thermal expansion of the electrolyte copper foil, which is measured using a thermomechanical analyzer (TMA) while heating the electrolytic copper foil from 30 °C to 190 °C at a speed of 5 °C/min, ranges from 16 to 22 µm/(m·°C), a tensile strength of the electrolytic copper foil, which is measured after a heat treatment at a temperature of 190 °C for 1 hour, ranges from 21 to 36 kgf/mm<2>, and a weight deviation of the electrolytic copper foil is 5% or less.