NOVELTY - The assembly (200) has module units arranged in a cartridge. Unit cells are electrically connected with a bus-bar. A base plate is provided with multiple sub-modules and a battery management system (BMS). A side part cover plate (240) is mounted on the sides of the sub modules. A front side cover plate (260) is arranged in upper sides of the sub-modules that are arranged on a front side of a top cover plate (250). The front side cover plate is formed with through grooves for extending communication ports from the front side cover plate.    USE - Secondary battery module assembly for a battery pack of a power source device that is utilized as a household power apparatus, an industrial power apparatus, a commercial power apparatus, a public facilities power supply unit, a power supply unit for big shop, an emergency power package, a computer center power supply unit, a portable power supplier, an armarium power supply unit, a fire extinguishing system power supply unit, an alarm equipment power supply unit, a fire escape apparatus power supply unit and a power source of a wireless mobile device, an electric vehicle, a hybrid electric vehicle or plug-in hybrid electric vehicle (all claimed).    ADVANTAGE - The communication ports of the BMS are exposed from the front side cover plate so as to facilitate expansion and connection of a communication unit with the assembly. The assembly supplies electricity according to need of a user by using the BMS so as to improve electricity usage efficiency. The assembly enlarges capacity of a battery module. The assembly maintains stable structure of the battery module so as to improve safety and operational efficiency of the battery module. The assembly protects the battery module from over-voltage, excess current and heat generation.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a power source device.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a secondary battery module assembly.    Secondary battery module assembly (200)    Side part cover plate (240)    Top cover plate (250)    Front side cover plate (260)