NOVELTY - The secondary battery (100) has an electrode assembly (10) and electrolyte accommodated in a case (40). An electrode terminal (20) electrically connected to the electrode assembly, has a terminal housing (21). A cap plate seals the case and the terminal housing penetrates through the cap plate. A seal gasket surrounds a lower portion of the terminal housing. The electrode terminal has a laterally protruding section on a portion of the terminal housing protruding outside the case, and the seal gasket is in close contact with a lower end of the protruding section.    USE - Secondary battery for use in hybrid electric vehicle and portable electronic device such as cellular phone and camcorder.    ADVANTAGE - The seal gasket can surround a lower portion of the terminal housing of the electrode terminal, thus preventing electrolyte from infiltrating into a gap between the electrode terminal and the cap plate and preventing unnecessary and undesirable electrical short-circuits due to a reduction in the breakdown voltage between the electrode terminal and the cap plate. The seal gasket can prevent external moisture from infiltrating into the case through the cap plate, thus preventing unnecessary electrical short-circuits. The seal gasket can have the shape of a hollow tube to surround the lower portion of the terminal housing and the seal gasket can surround a lower perimeter of the terminal housing in a tubular shape, thus preventing the electrolyte from leaking out of the case through a gap between the terminal housing and the cap plate. The side surface of the lower portion of the seal gasket can be brought into close contact with the portion of the lower insulation portion, thus further enhancing sealing efficiency of the battery. The terminal housing can be riveted and finally assembled with the case after assembling components of the secondary battery, excluding the case, thus facilitating manufacture of the secondary battery. A sill can be on the lower insulation portion and a seating portion securely placed on the sill can be on the flange, thus enhancing the sealing efficiency between the flange of the seal gasket and the cap plate. The formation of a gap between each of the electrode terminals and the cap plate may be prevented, hence the electrolyte cannot come into contact with the cap plate, thus battery deterioration can be prevented and battery capacity can be maintained. The electrolyte cannot leak outside the battery case through the gap between each of the electrode terminals and the cap plate, thus preventing corrosion to various components outside the battery case. The external moisture cannot infiltrate into the battery case through the gap.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the secondary battery.    Electrode assembly (10)    Electrode terminal (20)    Terminal housing (21)    Case (40)    Secondary battery (100)