Disclosed herein is a battery pack, which comprises a connecting member including an insulation frame mounted to the upper end of a battery cell and a pair of connection protrusions formed at the upper end surface of the frame, the connection protrusions being in contact with electrode terminals of the battery cell, a protection circuit module (PCM) mounted to the connecting member, the PCM including connection grooves, into which the connection protrusions are inserted such that the PCM can be coupled to the connecting member, and which are connected to a protection circuit, and a cap housing coupled to the connecting member or the battery cell while the PCM is surrounded by the cap housing.