Secondary battery comprising a detachable current collector

A secondary battery (100) is disclosed which comprises an electrode assembly (110), a case (120) containing the electrode assembly (110), a cap plate (150) sealing an opening of the case (120), an electrode terminal (135) protruding outside the case (120) and a collector for electrically connecting the electrode assembly (110) and the electrode terminal (130). The collector comprises a first collecting part (132) coupled to the electrode terminal (130) and including a first coupling portion and a second collecting part (133) coupled to the electrode assembly (110) and including a second coupling portion. The first coupling portion is coupled to the second coupling portion. One of the first and second coupling portions comprises a protrusion part (132b), and the other of the first and second coupling portions comprises an accommodation part (133a), the protrusion part (132b) being received in the accommodation part (133a).