NOVELTY - The battery (10) comprises: a flat winding electrode assembly formed by winding an elongated positive electrode and an elongated negative electrode with an elongated separator placed between the electrodes; and a prismatic outer body (25) storing the electrode assembly and a non-aqueous electrolyte. The positive and the negative electrodes include a positive electrode substrate exposed portion and a negative electrode substrate exposed portion respectively formed along a longitudinal direction. The electrolyte contains a lithium salt having an oxalate complex as an anion.    USE - The non-aqueous electrolyte secondary battery is useful as a power supply for: driving a portable electronic equipment such as smartphone, portable personal computer, personal digital assistant and portable music player; driving electric vehicles and hybrid electric vehicles; and in stationary storage battery systems for suppressing output fluctuation of solar power generation and wind power generation.    ADVANTAGE - The battery has excellent cycling characteristics, high safety, capacity, reliability and output characteristics.    DETAILED DESCRIPTION - The battery (10) comprises: a flat winding electrode assembly formed by winding an elongated positive electrode and an elongated negative electrode with an elongated separator placed between the electrodes; and a prismatic outer body (25) storing the electrode assembly and a non-aqueous electrolyte. The positive and the negative electrodes include a positive electrode substrate exposed portion and a negative electrode substrate exposed portion respectively formed along a longitudinal direction. The electrolyte contains a lithium salt having an oxalate complex as an anion at the time of making the battery. An area of the negative exposed portion is greater than 700 cm2, and the area of the positive exposed portion is greater than 500 cm2, where the area of the negative portion is larger than the area of the positive portion. The area of the negative portion is 5-30% of area of negative electrode active material mixture layers formed on both sides of the negative electrode, and the area of the positive portion is 5-20% of area of positive electrode active material mixture layers formed on both sides of the positive electrode. The exposed portions are wound on respective ends of the assembly. The outer faces of each exposed portion is welded and connected to positive and negative electrode collectors respectively. The negative exposed portion is formed on both ends of the negative electrode in a width direction along the longitudinal direction. One of the negative exposed portions is wider than the other, and the wider substrate portion is connected to the negative electrode collector. The positive exposed portion is formed only on one side of the positive electrode in a width direction along the longitudinal direction. The battery has capacity of greater than 4 Ah. The electrolyte contains lithium difluorophosphate at the time of making the battery.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic plan view of a prismatic non-aqueous electrolyte secondary battery.    Non-aqueous electrolyte secondary battery (10)    Positive electrode terminal (18)    Outer body (25)    Electrolyte pour hole (26)    Gas exhaust valve. (28)