NOVELTY - A safety device of a battery comprises pressure releasing unit (410) configured to release an internal pressure within the cell (400) when the internal pressure of the cell exceeds a predetermined set pressure; and space forming member covering the pressure releasing unit and configured to form an empty space around the pressure releasing unit.    USE - The safety device is used for a battery for mobile communication terminal (claimed).    ADVANTAGE - The device improves the safety of the battery by smoothly releasing the internal pressure of the battery when the internal pressure reaches or exceeds a predetermined set pressure.    DETAILED DESCRIPTION - A safety device of a battery comprises:    (A) pressure releasing unit provided at a cell of the battery, the pressure releasing unit configured to release an internal pressure within the cell when the internal pressure of the cell exceeds a predetermined set pressure; and    (B) space forming member covering the pressure releasing unit and configured to form an empty space around the pressure releasing unit such that when the internal pressure of the cell exceeds the predetermined set pressure, the released internal pressure is released into the empty space formed by the space member.    An INDEPENDENT CLAIM is also included for battery for a mobile communication terminal, comprising:    (A) battery cell configured to provide a power source for the mobile terminal;    (B) protection circuit assembly attached to a surface of the battery cell and configured to stabilize the power source within the battery cell when the battery is charged or discharged;    (C) cover member (600) configured to cover the protection circuit assembly and to couple the protection circuit assembly to the battery cell;    (D) pressure releasing unit configured to release an internal pressure within the cell when the internal pressure of the cell exceeds a predetermined set pressure; and    (E) space forming member covering the pressure releasing unit and configured to form an empty space around the pressure releasing unit such that when the internal pressure of the cell exceeds the predetermined set pressure, the released internal pressure is released into the empty space formed by the space member.    DESCRIPTION OF DRAWING(S) - The figure is a sectional view showing a battery safety device.    Cell (400)    Pressure releasing unit (410)    Groove (411)    Thin film portion (412)    Cover member (600)    Space forming cap (700)    Auxiliary pin (800)