| 摘要 |
PROBLEM TO BE SOLVED: To provide a large-capacity lithium secondary battery in which the unsticking and loosening of an electrode are suppressed by relaxing a stress applied to the electrode, and which is less prone to suffer the deterioration owing to charge and discharge cycles.SOLUTION: The lithium ion secondary battery comprises: a wound group including positive and negative electrodes capable of absorbing and releasing lithium ions reversibly and wound with a separator interposed therebetween; and an organic electrolytic solution in which an electrolyte containing the lithium ions is dissolved. The negative electrode is formed by applying a mixture layer including an active material and a binder to a current collector. The current collector includes: a copper foil; and a stress relaxation layer provided on at least one of front and rear faces of the copper foil and having an internal stress. |
