NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

A prismatic nonaqueous electrolyte secondary battery includes a flat winding electrode assembly formed by winding an elongated positive and negative electrodes with an elongated separator interposed therebetween, and an outer body storing the flat winding electrode assembly and a nonaqueous electrolyte. The positive electrode includes a positive electrode substrate exposed portion formed along a longitudinal direction. The negative electrode includes a negative electrode substrate exposed portion formed along a longitudinal direction. The nonaqueous electrolyte contains at least one of a lithium salt having an oxalate complex as an anion and lithium difluorophosphate (LiPF2O2) at the time of making the nonaqueous electrolyte secondary battery. The flat winding electrode assembly has eight or more layers of a winding portion formed only of the separator in its central portion. This battery can allow a nonaqueous electrolyte having a high viscosity to easily penetrate the inside of a flat winding electrode assembly.

主权项

1. A nonaqueous electrolyte secondary battery comprising:
a flat winding electrode assembly formed by winding an elongated positive electrode and an elongated negative electrode with an elongated separator interposed therebetween; and an outer body storing the flat winding electrode assembly and a nonaqueous electrolyte, the nonaqueous electrolyte containing at least one of a lithium salt having an oxalate complex as an anion and lithium difluorophosphate (LiPF2O2) at the time of making the nonaqueous electrolyte secondary battery, and the flat winding electrode assembly having eight or more layers of a winding portion formed only of the separator in the central portion thereof.