Square secondary battery, battery module, storage device, vehicle, and flying object

A rectangular secondary battery, comprising:

• an outer can formed in a shape of a bottomed cylinder having a cross-sectional shape of a substantially quadrangular shape, the outer can having an opening;
• a power generation element contained in the outer can;
• and
• a lid having a positive electrode terminal and a negative electrode terminal, the lid covering the opening of the outer can, wherein
• four convex portions exist on each of one or more sides of a side surface of an outer surface of the outer can, a bottom surface of the outer surface of the outer can, and a surface having the positive electrode terminal, and the negative electrode terminal being the outer surface of the lid,
• each of the convex portions on the side surface of the outer can exist within a range of 10 mm or less from each of corners of respective of the side surface of the outer surface of the outer can,
• each of the convex portions on the bottom surface of the outer can exist within a range of 10 mm or less from each of corners of respective of the bottom surface of the outer surface of the outer can, and
• each of the convex portions on the lid of the outer can exist within a range of 10 mm or less from each of corners of respective of the surface having the positive electrode terminal and the negative electrode terminal of the outer surface of the lid.