Secondary battery

A secondary battery comprises a bare cell including an electrode terminal, a protection circuit module PCM mounted to the bare cell, the PCM comprising a protection circuit board PCB and a first planar connector between the bare cell and the PCB at a first end of the PCB for electrically connecting the PCM to the bare cell. A second planar connector may be provided between the bare cell and the PCB at a second end of the PCB opposite the first end, wherein the second planar connector is arranged to electrically connect the PCM to the bare cell or comprises a dummy connector having substantially the same thickness as the first planar connector.