a chargeable battery module installed in an electric car for driving the electric car includes a compartment for containing a plurality of chargeable batteries , and circuits of each chargeable battery are connected in series or in parallel and installed between each chargeable battery and an upper casing or a lower casing of the compartment , and each chargeable battery is combined for use , and the chargeable batteries including a single chargeable battery or a module of parallelly connected chargeable batteries can be charged easily without requiring a charging protection plate , and all single batteries can be fully charged with a constant voltage to provide the best cycle life of the chargeable batteries and maintain the best battery life for the electric car .