The present invention is characterized in that a nonaqueous electrolyte contains
a sultone compound having unsaturated bonds, and the present invention thereby
aims at suppressing the swelling of a nonaqueous electrolyte secondary battery,
as represented by a lithium secondary battery, after being allowed to stand at
a high temperature and at obtaining an excellent high temperature standing performance.
Furthermore, by making the nonaqueous electrolyte contain, in addition to the sultone
compound containing unsaturated bonds, a vinylene carbonate derivative in 1.0 wt
% or below, and/or a cyclic sulfate in 2.0 wt % or below, there can be obtain a
nonaqueous electrolyte secondary battery which prevents the initial discharge capacity
degradation, occurring when the addition amount of the sultone compound having
unsaturated bonds is increased, and has an excellent high temperature standing
performance and a large initial discharge capacity.