In a lithium polymer battery of the present invention, a positive electrode,
an
negative electrode and a separator respectively contain a vinylidene fluoride-hexafluoropropylene
copolymer, an electrolyte contains a solvent comprising diethyl carbonate and a
solute dissolved in the solvent, and the electrolyte further contains diphenyl
ether as an additive.
With the use of the above electrolyte, it is possible to improve the thermal
stability of the battery containing P(VDF-HFP) in the positive electrode, the negative
electrode and the separator and to operate the shutdown function surely, thereby
ensuring the excellent safety of the battery.
