| 摘要 |
PROBLEM TO BE SOLVED: To obtain a negative electrode collector copper foil for a lithium ion secondary battery, improving injection properties of an electrolyte without lowering capacity, and a lithium ion secondary battery.SOLUTION: A collector copper foil 7 in which a plurality of grooves 10 serving as a passage of an electrolyte are disposed is used on at least one of main surfaces of a negative electrode active material layer. The grooves are linear and in parallel with each other. The width w of each groove is 5-20 μm, the depth d of each groove is 1-5 μm, and the pitch P between the grooves is 3,000-5,000 μm. The grooves are formed by using a reduction roll including a protrusion. |
