| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative electrode collector for lithium ion secondary battery having a high strength and a large discharge capacity.SOLUTION: The negative electrode collector uses a copper coated steel foil 10 for carrying the negative electrode active material of a lithium ion secondary battery having a steel sheet 6 composed of a ferritic stainless steel as a core, a copper coating layer 7 having an average thickness tof 0.02-5.0 μm per one side on both sides thereof, an average thickness t of 3-100 μm including the copper coating layer 7 and the t/t of 0.3 or less. Common steel, austenitic stainless steel, or ferritic stainless steel is applicable as the steel sheet 6. The copper coating layer 7 is an electrolytic copper plating layer (including that rolled after plating), for example. A carbon-based active material layer the density of which is increased by a strong roll press, for example, is formed on the surface of the copper coating layer 7, and the negative electrode collector is composed of the copper coated steel foil 10 and the carbon-based active material layer. |
