Negative electrode current collector copper foil for lithium ion secondary battery, negative electrode for lithium ion secondary battery, lithium ion secondary battery, and method for producing negative electrode current collector copper foil for lithium ion secondary battery

摘要

PROBLEM TO BE SOLVED: To enhance adhesiveness with a negative electrode active material layer.SOLUTION: A negative-electrode copper foil collector 10 for a lithium ion secondary battery is used for carrying a silicon-based negative electrode active material layer 15a (15b) and a tin-based negative electrode active material layer 15a (15b), and comprises a copper foil made of copper or copper alloy, and granular electrodeposits deposited on at least one face of the copper foil through a surface roughing process. An average particle diameter of the granular electrodeposit is 0.4 m or larger and smaller than 1.0 m, and the number of the granular electrodeposit having a particle diameter of 0.2 m or larger and smaller than 1.5 m is 150 pieces or more but less than 650 pieces per 100 mof a surface area of the copper foil.