| 摘要 |
PROBLEM TO BE SOLVED: To enhance the cycle reliability and storage stability of a lithium secondary battery by using a nonaqueous electrolyte of a solvent containing the specified amount of a specific non-conjugated unsaturated cyclic hydrocarbon compound in the secondary battery having a carbon material negative electrode and a lithium-containing oxide positive electrode. SOLUTION: A belt-shaped negative electrode 2 made of a carbon material such as flake high crystallized graphite capable of absorbing/releasing lithium and a belt-shaped positive electrode 1 made of a lithium-containing oxide such as LiCoO2 are stacked and wound through a porous separator 5. The spirally wound electrode body obtained is housed in a battery container 6 together with a nonaqueous electrolyte, and lead terminals 3, 4 are fixed to obtain a nonaqueous electrolyte lithium secondary battery. As a solvent occupying 80-90% of the nonaqueous electrolyte, ethylene carbonate or the like is used, and 10-20vol.% non-conjugated unsaturated cyclic hydrocarbon compound having a plurality of double bonds and 6-12 carbon atoms is added to the ethylene carbonate or the like. As the solute of the nonaqueous electrolyte, a lithium salt such as lithium hexafluorophosphate is used. |
