collecting regions 13 and 14 and the electrode terminals 41 and 42 may be placed on at least one of the pair of first sides 101 the first sides 101 may be the short sides of the electrode assembly 10 and the second sides 102 may be the long sides thereof fig3 is a partial amplified sectional view of the electrode assembly shown in fig2 referring to fig1 to fig3 the separators 20 can each include a center 21 facing at least one of the positive and negative electrode plates 11 and 12 and overlapped therewith and a pair of extensions including bent portions 22 and adhered portions 23 extended from the center 21 to the outside of the positive and negative electrode plates 11 and 12 the pair of extensions including portions 22 and 23 may be placed at the second sides 102 where the current collecting regions 13 and 14 and the electrode terminals 41 and 42 are absent the extensions may be overlapped with each other at the second sides 102 and may be tightly adhered to each other at the edges thereof in a body so as to form adhered portions 23 the adhered portions 23 may be formed by melting and pressing the surfaces of the separators 20 together for example through thermal welding or ultrasonic welding such that the positive and negative electrode plates 11 and 12 are stably fixed between the centers 21 of the separators 20 the adhered portions 23 are connected to the bent portions 22 of all the separators 20 provided in the electrode assembly 10 so.