Method of manufacturing nonaqueous electrolyte secondary battery

A method of manufacturing a nonaqueous electrolyte secondary battery, comprising the steps of:

• providing a positive electrode that contains a positive electrode active material and a negative electrode that contains a negative electrode active material, at least one of the provided positive electrode and negative electrode including a sodium (Na) ingredient as an incidental impurity;
• producing an electrode assembly from the provided positive electrode and negative electrode;
• producing a battery assembly in which the electrode assembly is housed in a battery case;
• injecting a nonaqueous electrolyte solution into the battery case, the nonaqueous electrolyte solution including at least, as additives, lithium bis(oxalato)borate and a fluorophosphate compound in which fluorine and phosphorus serve as structural elements and, as nonaqueous solvents, a carbonate solvent and an ether solvent, a ratio (A/B) between the molar concentration A of the fluorophosphate compound and the molar concentration B of the lithium bis(oxalato)borate being from 2.5 to 5, and the amount of ether solvent included in the nonaqueous electrolyte solution being less than 10 vol % when the amount of nonaqueous solvent included in the nonaqueous electrolyte solution is set to 100 vol %;
• and
• charging the battery assembly to a predetermined charge voltage, then discharging the battery assembly to a predetermined discharge voltage.