Lithium ion secondary battery, current collector constituting the negative electrode of the secondary battery, and electrolytic copper foil constituting the negative electrode current collector

摘要

Provided are: an electrolytic copper foil, which has similar surface configurations on both surfaces, good wettability with an active material slurry and high battery capacity, while being suppressed in deterioration of the battery capacity even if charge and discharge cycles are repeated, and wherein the active material coating film layer is not easily separated from the copper foil that serves as the negative electrode collector; and a lithium secondary battery which uses the electrolytic copper foil as a collector. An electrolytic copper foil for negative electrode collectors of lithium ion secondary batteries, wherein the both surfaces of the electrolytic copper foil are electrolytically deposited surfaces and the electrolytically deposited surfaces are composed of a columnar crystal structure. A negative electrode for lithium secondary batteries, which uses the electrolytic copper foil as a collector. A lithium secondary battery in which the negative electrode is incorporated. A first surface of the electrolytic copper foil is a surface that is formed on a drum surface by electrolytic deposition of copper of a columnar crystal structure, and a second surface that is on the reverse side of the first surface is a surface that is formed on the back side of the first surface by electrolytic deposition of copper of a columnar crystal structure after the foil formation of the first surface.