NOVELTY - Secondary battery comprises electrode plate (61) having a mixture layer (612) containing an active material in a part of a surface(s) of metal current collector foil (611). The current collector foil has coated region (P1) where the mixture layer exists and uncoated region (P2) where mixture layer does not exist. The thickness TA of the coated region is greater than the thickness TB of the uncoated region of the current collector foil.    USE - Secondary battery i.e. lithium ion secondary battery (claimed) used as power supply. Uses include but are not limited to portable personal computer, mobile telephone, hybrid vehicle, or electric vehicle.    ADVANTAGE - The uncoated region is easily extended compared with the coated region. Thus, during electrode plate rolling, smaller pressure is received in the uncoated region compared with the coated region. The difference of stretch amount between the coated region and uncoated region is small, so that reduction of electrode plate curving is achieved.    DETAILED DESCRIPTION - Secondary battery comprises electrode plate (61) having a mixture layer (612) containing an active material in a part of a surface(s) of metal current collector foil (611); separator; electric power generation component formed by stacking alternately on both sides of the electrode plate and separator; current collection terminal electrically connected with the current collector foil. The current collector foil has coated region (P1) where the mixture layer exists, where coated region is located in thickness direction of the foil; and uncoated region (P2) where mixture layer does not exist, where the uncoated region is located in one edge part of the width direction of the current collector foil. The thickness TA of the coated region is greater than the thickness TB of the uncoated region of the current collector foil.    DESCRIPTION OF DRAWING(S) - The drawing is a cross-sectional view showing an edge part structure of electrode plate.    Electrode plate (61)    Metal current collector foil (611)    Mixture layer (612)    Coated region (P1)    Uncoated region (P2)