NOVELTY - A rechargeable battery pack comprises a core pack having an electrode assembly that has a positive electrode plate, a separator and a negative electrode plate, a sheath for sealing the electrode assembly with an electrolyte, and a protective circuit module; a case adapted to seat and fix the core pack; an adhesive coupling the core pack to a bottom surface of the case; and a cover covering the case and having at least one trench.    USE - The pack, i.e. a battery or an auxiliary battery, is used as a power source.    ADVANTAGE - The pack allows the core pack to be easily separated from the case.    DETAILED DESCRIPTION - A rechargeable battery pack comprises a core pack (110) having an electrode assembly, a sheath (115) for sealing the electrode assembly with an electrolyte, and a protective circuit module (117), where the electrode assembly includes a positive electrode plate, a separator and a negative electrode plate; a case (120) adapted to seat and fix the core pack; an adhesive (130) that couples the core pack to a bottom surface (121) of the case; and a cover (140) that covers the case. The case has at least one trench (122) formed on a surface on which the core pack is positioned.    An INDEPENDENT CLAIM is also included for a method of separating a core pack from a case, comprising preparing the core pack including the electrode assembly, the electrolyte, the sheath and the protective circuit module; gluing the core pack to a surface of the case using an adhesive; testing the adhesion strength between the core pack and the case and, if the test result is out of a reference range, dipping the core pack and the case into a solution to a predetermined depth; and separating the core pack from the case.    DESCRIPTION OF DRAWING(S) - The figure is an exploded perspective view of a rechargeable battery pack.    Core pack (110)    Sheath (115)    Protective circuit module (117)    Case (120)    Bottom surface (121)    Trench (122)    Adhesive (130)    Cover (140)