NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

Provided is a non-aqueous electrolyte secondary battery including: a plurality of electrode groups each formed by winding a positive electrode, a negative electrode, and a separator into a flat shape; a non-aqueous electrolyte; and a prismatic case accommodating the electrode groups and the non-aqueous electrolyte. The case has a rectangular cross-sectional shape. The electrode groups are accommodated in the case such that lateral directions of the cross-sectional shapes of the electrode groups are each perpendicular to the lateral direction of the cross-sectional shape of the case, and the axis directions of the electrode groups are each parallel with the height direction of the case.