NOVELTY - The battery unit (1) has a terminal element comprising a current collector electrically coupled to an electrode assembly (10). A terminal portion extends parallel to an upper surface of a cap plate (310) to an outside of the cap plate. A connection portion is electrically coupled to the current collector and the terminal portion. A fixing element is arranged in a terminal insertion portion, and fixes the terminal element to the cap plate. The fixing element comprises injection-molded plastic resin in the terminal insertion portion and surrounds the terminal element.    USE - Battery unit i.e. secondary battery e.g. lithium ion battery, for use as energy sources in a battery module (claimed) for various applications. Uses include but are not limited to mobile devices i.e. mobile phones, electric vehicles, hybrid cars, electric bikes and uninterruptable power supplies.    ADVANTAGE - The battery unit provides a large contact area between a positive current collector and a positive material uncoated portion so as to reduce contact resistance. The battery unit forms the positive terminal element and the negative terminal element without performing coupling process by welding, thus reducing manufacturing cost while maintaining electrical characteristics of a current path from the positive current collector and the negative current collector to the positive terminal portion and the negative terminal portion, respectively. The battery unit prevents intrusion of moisture into a case through gaps between the positive and negative terminal fixing elements and the positive and negative terminal insertion portions, thus reducing possibility of corrosion of the cap plate, the electrode assembly, the positive and negative current collectors and the case.    DETAILED DESCRIPTION - The terminal insertion portion comprises a positive terminal insertion portion (35) and a negative terminal insertion portion (36). The fixing element comprises a positive terminal fixing element (340) and a negative terminal fixing element (350). The terminal portion comprises a positive terminal portion (321) and a negative terminal portion (331). The current collector comprises a positive current collector (324) and a negative current collector (334). The terminal element comprises a positive terminal element (320) and a negative terminal element (330), where the positive terminal element comprises aluminum (Al) and the negative terminal element comprises copper (Cu). An INDEPENDENT CLAIM is also included for a battery module.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded perspective view of a battery unit.    Battery unit (1)    Electrode assembly (10)    Positive terminal insertion portion (35)    Negative terminal insertion portion (36)    Cap plate (310)    Positive terminal element (320)    Positive terminal portion (321)    Positive current collector (324)    Negative terminal element (330)    Negative terminal portion (331)    Negative current collector (334)    Positive terminal fixing element (340)    Negative terminal fixing element (350)