NOVELTY - The battery pack has a module assembly (120) arranged with multiple battery modules (110) that are provided with multiple unit cells. A pair of side plates (130) is combined with a specific structure that is circled around two sides of the module assembly. An outer cover is combined with a base plate (140) when the outer cover is surrounded with the module assembly of the structure. The base plate is provided with an outer installation part that is mounted on an external structure. A connecting part is combined with a side of the side plates.    USE - Battery pack for a power storage device, a wireless mobile device and a vehicle e.g. electric vehicle and hybrid electric vehicle/plug-in hybrid electric vehicle, in a home and an industry (all claimed). Uses include but are not limited to a power storage device e.g. household power apparatus, public facilities power supply unit, big shop power supply unit, emergency power package, computer center power supply unit, portable power supplier, armarium power supply unit, fire extinguishing system power supply unit, alarm equipment power supply unit and fire escape apparatus power supply unit.    ADVANTAGE - The battery pack ensures that a power storage system stores energy when power demand is less, so that an electricity supplying apparatus can easily supply power during overload/emergency condition, thus improving power quality and energy usage efficiency. The battery modules are provided with multiple battery cells that are electrically connected together in a serial/concurrent mode so as to improve expandability and structural stability of the battery pack and reduce manufacturing cost. The battery pack positionally separates a power wire harness part and a communication wire harness part so as to prevent malfunction, short circuit and explosion and noise from being generated in the communication wire harness part by grounding a power line of the power wire harness with the base plate, thus improving structural safety of the battery pack.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a power storage device.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a battery pack.    Battery modules (110)    Module assembly (120)    Side plates (130)    Base plate (140)    Transportation handle (160)