NOVELTY - The module has an electrode assembly placed in a case. A current collector is placed in the case, and is electrically connected to the electrode assembly. A cap plate (310) covers the case, and includes a terminal inserter penetrating the cap plate. A terminal part includes a terminal plate outside the case and a connector connecting the current collector to the terminal plate through the terminal inserter. A fixing unit fixes the terminal part into the cap plate. A groove pattern is placed in an area of the cap plate adjacent to a safety vent (32).    USE - Lithium-ion battery module for use in a mobile device i.e. cellular phone, electric car, hybrid car, electric bicycle and uninterruptible power supply. Can also be used for a cylindrical battery module, rectangular battery module and a polymer battery module.    ADVANTAGE - The module forms the groove pattern in any suitable position and shape to be adjacent to a safety vent in consideration of the position, shape and number of notches formed in the safety vent, so that the groove pattern can be formed in an upper surface of the cap plate or in upper and lower surfaces of the cap plate, thus improving combination strength between positive and negative terminals and the cap plate. The module performs friction stir welding (FSW) between dissimilar metals instead of laser welding, so that combination process into the single body by welding is not necessary, thus reducing manufacturing cost. The module changes position, a shape and a number of the notch in the safety vent to ease gas discharge caused by increase in internal pressure of the battery module, thus minimizing damage to the safety vent when performing ultrasonic welding with respect to the electrode assembly and the current collectors.    DETAILED DESCRIPTION - The current collector is one of a positive current collector and a negative current collector. The terminal plate is one of a positive terminal plate and a negative terminal plate.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of a shape of a groove pattern in a lower surface of a cap plate.    Groove (G)    Safety vent (32)    Cap plate (310)