Abstract: In a method for sealing a substantially straight intercell connector bar passing through an opening in the upper part of an intercell partition of an electric storage battery, a mould is used having a marginal portion fitting against the face of the partition and defining a cavity, the mould comprising a body open at the bottom, and a closure movable horizontally from a closed position in which it extends under the bar to close the bottom of the cavity, to an open position in which it permits removal of the mould. The closure is formed with a cutter portion arranged to gouge or broach a groove in the upper or lower surface of the bar to ensure leak-proof closure of the mould.