Patent attributes
A non-aqueous electrolyte secondary battery including: a positive electrode; a negative electrode, and a non-aqueous electrolyte. The negative electrode includes a negative electrode active material that includes at least Si. The non-aqueous electrolyte includes lithium hexafluorophosphate as a main supporting electrolyte and has an acid content of not less than 50 ppm and not more than 200 ppm. The negative electrode has a potential of not less than 0.6 V and not more than 1.5 V relative to a Li electrode at an end-of-discharge voltage of the battery. The battery is prevented from suffering degradation of storage characteristics caused by the dissolution reaction of Si from the negative electrode during charging and the precipitation reaction of the dissolved Si.