2 2 2 COPPER ALLOY FOIL NEGATIVE ELECTRODE FOR LITHIUM ION SECONDARY BATTERY LITHIUM ION SECONDARY BATTERY METHOD FOR MANUFACTURING COPPER ALLOY FOIL AND METHOD FOR MANUFACTURING NEGATIVE ELECTRODE FOR LITHIUM ION SECONDARY BATTERY

摘要

(Problem) Sufficient mechanical strength is maintained stably even after the heat treatment in the manufacturing process of the negative electrode for a lithium ion secondary battery. (Measures) 0.20 mass% or more and 0.40 mass% or less Cr, 0.01 mass% or more and 0.10 mass% or less Ag, and 0.10 mass% or more and 0.20 mass% or less Sn are contained, and remainder consists of Cu, and Cr employment index Z of (1) becomes 0.4 or less. Z = (R _M -R _S ) / (R _P -R _S ) ... (1) However, R _M is actual value (% IACS) of the conductivity R of the copper alloy foil 10, and R _S is the Cr the calculated value (% IACS) of the conductivity of copper alloy foil R 10 in the case is employed, _{R P} is the calculated value of the conductivity of copper alloy foil R 10 (% IACS) of when all of the Cr deposition.