Charge-discharge cycle performance is improved in a lithium secondary
battery that adopts a thin film made of silicon or a silicon alloy as its
negative electrode active material and has a wound electrode structure.
The lithium secondary battery includes: a negative electrode having a
current collector and a thin film made of silicon or a silicon alloy as a
negative electrode active material, the thin film provided on the current
collector; a positive electrode; a separator; the positive and negative
electrodes being overlapped with the separator interposed therebetween,
and the positive and negative electrodes and the separator being wound
around to form an electrode assembly; a non-aqueous electrolyte; and a
battery case accommodating the electrode assembly. The ratio of
theoretical capacity per unit area of the negative electrode to charge
capacity per unit area of the positive electrode is within the range of
from 1.9 to 4.4.