NOVELTY - A lead storage battery (1) consists of a battery case (2) which accommodates cells, an inside cover (3) with which a concave portion (31) is formed in the surface while covering the opening of the upper end of the battery case, and an upper cover (4) which covers the concave portion of the inside cover. Exhaust-gas chambers (37) are connected and adjoined while forming an exhaustion chamber in the space surrounded by the upper cover of the concave portion. A detent plug (7) is installed in the position corresponding to the opening of inside cover.    USE - Lead storage battery is used for vehicles.    ADVANTAGE - The lead storage battery is provided with an exhaustion structure which discharges gas without escape of electrolyte solution. Even when variation arises with respect to liquid level between cells, the battery can be made to carry out water supplement by opening of the detent plug.    DETAILED DESCRIPTION - A lead storage battery (1) consists of a battery case (2) which accommodates cells, an inside cover (3) with which a concave portion (31) is formed in the surface while covering the opening of the upper end of the battery case, and an upper cover (4) which covers the concave portion of the inside cover. Exhaust-gas chambers (37) are connected and adjoined while forming an exhaustion chamber in the space surrounded by the upper cover of the concave portion. An opening (48), exhaust-gas port, and electrolyte-solution recirculation opening for injection are provided in the inside cover corresponding to each cell. The battery is provided with a mechanism which centralizes the gas emitted from the gas-exhaust port on an intensive exhaust-gas chamber (45) through the exhaustion chamber, and carries out package exhaustion out of the battery. A mechanism is provided for returning the moisture content discharged with gas to the cell from the electrolyte-solution recirculation opening. A detent plug (7) is installed in the position corresponding to the opening of inside cover.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of the upper cover removed from the lead storage battery.    Lead storage battery (1)    Battery case (2)    Inside cover (3)    Upper cover (4)    Detent plug (7)    Concave portion (31)    Exhaust-gas chamber (37)    Intensive exhaust-gas chamber (45)    Opening (48)