A secondary battery includes a first electrode plate including a first active material coated area in which a first substrate is coated with a first active material and a first non-coated area not coated with the first active material; a second electrode plate including a second active material coated area in which a second substrate is coated with a second active material and a second non-coated area not coated with the second active material; and a separator interposed between the first and second electrode plates, wherein at least one of the first and second electrode plates includes an electrode assembly having a waveform boundary section between one active material coated area and one non-coated area. A manufacturing method of such secondary battery is also disclosed.