An accumulator (6) comprises a battery housing subdivided into cell vessels, a plurality of positive and negative electrode plates which are separated by separators and stacked in parallel to give electrode plate stacks, and a lower cover (8) tightly obturating the cell vessels. The accumulator is provided with openings (9) on the lower cover (8) for the cell vessels, said openings running into a degassing channel system (1) placed on the lower cover (8). Annular elevations (18) are formed onto the lower cover (8) next to each opening (9). The degassing channel system (1) is provided with fastening means (12, 21, 22) for bracing the degassing channel system (1) on the lower cover (8) in such a manner that the elevations (18) seal the openings (9) leading towards the degassing channel system (1) by surface pressure.