Abstract: A retaining cap having an open top and a plurality of openings in the bottom wall thereof corresponding in size, shape and spacing to the poles of the battery cells which protrude to the upper ends of the cells is assembled between selected poles of adjacent cells. After the conventional connecting link is then assembled to the adjacent terminals, a sealing compound, preferably a room temperature curing, silicon rubber compound in the polysiloxane family with a curing agent or solution from the dimethyl polysiloxane family is poured into the open top of the cap to encapsulate the intercell connecting link and the protruding poles of the cells. The sealing mixture is characterized by its flowability in the uncured state, its propensity to reseal itself after being ruptured, its usefulness throughout a broad range of operating temperatures, its non-adherence to styrenes and lead, and its resistence to sulfuric acid.