Nonaqueous electrolyte secondary battery

The non-aqueous electrolyte secondary battery includes an electrode body including a positive electrode plate and a negative electrode plate, a square exterior body having an opening and housing the electrode body, a sealing plate closing the opening, and an electrode terminal provided on the sealing plate. The positive electrode plate comprises a positive electrode core body and positive electrode active materials coated on two surfaces of the positive electrode core body, and the perimeter of a coating part of the positive electrode active materials on the positive electrode core body is less than 0.28 m/Ah per unit capacity of the battery. 非水电解质二次电池包括：包括正极板和负极板的电极体、具有开口且收纳所述电极体的方形外装体、封闭所述开口的封口板、设置在所述封口板上的电极端子。所述正极板包括正极芯体和涂布在该正极芯体两面上的正极活性物质，电池的每单位容量的、所述正极芯体上的所述正极活性物质的涂布部的周长在0.28m/Ah以下。