Method for producing non-aqueous electrolyte solution, non-aqueous electrolyte solution, and non-aqueous electrolyte secondary battery

Abstract

A non-aqueous electrolyte secondary battery which uses a non-aqueous electrolyte solution in which a main component of a non-aqueous solvent is a fluorinated solvent, and by which it is possible to suitably prevent a decrease in battery capacity. A method for producing the non-aqueous electrolyte solution disclosed here includes a fluorinated solvent provision step for preparing the fluorinated solvent, a highly polar solvent provision step for preparing a highly polar solvent having a relative dielectric constant of 40 or more, a LiBOB dissolution step for preparing a highly concentrated LiBOB solution by dissolving LiBOB in the highly polar solvent at a concentration that exceeds the saturation concentration in the fluorinated solvent, and a mixing step for mixing the fluorinated solvent with the highly concentrated LiBOB solution.

What is claimed is: 
     
         1 . A non-aqueous electrolyte solution in which a lithium salt and LiBOB are dissolved in a non-aqueous solvent that contains a fluorinated solvent as a main component, wherein
 the non-aqueous solvent contains a highly polar solvent having a relative dielectric constant of 40 or more,   the volume of the fluorinated solvent is 80 to 95 vol % when the total volume of the non-aqueous solvent is taken as 100 vol %, and the concentration of LiBOB is 0.1 M or more.