This utility model discloses a secondary battery and an electrical device, belonging to the field of battery technology. The secondary battery includes a wound
cell, which includes a flat region and a corner region. The wound
cell includes a positive
electrode, a negative
electrode, and a separator between the positive and negative
electrode. The positive electrode includes a
positive current collector and a
flame-retardant layer and a positive active material layer sequentially disposed on at least one surface of the
positive current collector. This utility model controls the thickness relationship between the
flame-retardant layer and the positive active material layer in the flat region and the corner region, thereby significantly improving the
lithium plating phenomenon at the corner.