ANODE COLLECTOR COPPER FOIL FOR LITHIUM ION SECONDARY BATTERY, MANUFACTURING METHOD OF ANODE FOR LITHIUM ION SECONDARY BATTERY AND EVALUATION METHOD OF ANODE COLLECTOR COPPER FOIL FOR LITHIUM ION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide an anode collector copper foil for a lithium ion secondary battery of which the workability is improved by making cracking unlikely to occur when manufacturing an anode, in particular, during a roll press step, a manufacturing method of an anode for the lithium ion secondary battery and an evaluation method of the anode collector copper foil for the lithium ion secondary battery.SOLUTION: An anode collector copper foil is characterized in that, when the anode collector copper foil which is segmented for a fixed length in a length direction and of which the thickness is shorter than 26 m is cut in a short strip shape to form a plurality of copper foil pieces, an extension percentage which is a ratio of "a difference between a length of a longest copper foil piece and a length of a shortest copper foil piece" with respect to "the length of the shortest copper foil piece" is less than 220 ppm and when at least three copper foils which are positioned in a central portion and both end portions in a width direction of the anode collector copper foil are heated to a predetermined temperature of 120°C or higher and then cooled to a room temperature again, a difference between a maximum value and a minimum value of length variations before and after heating each of the copper foil pieces is equal to or less than 593 ppm.