COPPER FOIL OF NEGATIVE ELECTRODE COLLECTOR FOR LITHIUM ION SECONDARY BATTERY, NEGATIVE ELECTRODE FOR LITHIUM ION SECONDARY BATTERY, LITHIUM ION SECONDARY BATTERY, AND METHOD FOR MANUFACTURING COPPER FOIL OF NEGATIVE ELECTRODE COLLECTOR FOR LITHIUM ION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To suppress falling of roughed particles while maintaining high adhesion to a negative electrode active material layer and also improve weld strength with a tab lead, in a copper foil of a negative electrode collector for a lithium ion secondary battery.

SOLUTION: A copper foil of a negative electrode collector for a lithium ion secondary battery includes: a rolled copper foil made of copper or a copper alloy; and a first Cu plating layer, a roughed particle, and a second Cu plating layer which are at least provided in order on the rolled copper foil, and further includes one of a nickel-cobalt alloy plating layer, a nickel plating layer, and a cobalt plating layer. When Cb denotes a binder content Cb (wt.%) in a negative electrode active material layer, the surface roughness Ra of the copper foil satisfies a relation of Cb≥38×Ra×Ra-1.2×Ra (where, 0.10≤Ra≤0.72 and 2≤Cb≤20 are satisfied).

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