Abstract: A lid for an accumulator battery includes a substantially flat main closure element for closing a container of the battery, in which closure element holes are formed, a secondary closure element which is mounted on the main element and in which there are plugs that are fitted in the holes, and a duct which is formed in the secondary element, is in flow communication with the holes, and is provided for the discharge of the gases that are generated inside the battery container. The main and secondary elements of the lid together form a box-like structure defining a chamber which is in flow communication with the holes and inside which the main and secondary elements are connected to one another by partitions that extend perpendicularly relative to the plane in which the main element extends and are arranged in a manner such as to define a labyrinth which connects the holes of the main element with the gas-discharge duct.