ELECTROLYTIC COPPER FOIL, LITHIUM-ION SECONDARY CELL NEGATIVE ELECTRODE USING ELECTROLYTIC COPPER FOIL, LITHIUM-ION SECONDARY CELL, COPPER-CLAD LAMINATE AND PRINTED WIRING BOARD

摘要

Tensile strengths respectively measured using cut copper foils, which are obtained by cutting an electrolytic copper foil from one widthwise end thereof to the other end at 100 mm intervals, satisfy the following requirements (I) through (III). Requirement (I): Under normal conditions, the average value of the tensile strengths of the cut copper foils is 400 MPa to 650 MPa. Requirement (II): Under normal conditions, dispersion σ² of the tensile strengths of the cut copper foils is 18 [MPa]² or less. Requirement (III): The average value of the tensile strengths of the cut copper foils after being thermally treated at 150˚C for one hour is 350 MPa or higher.