A lead/accumulator with at least one separator made from filled microporous polyolefins is described, in which the formation of colored, mostly dark and often adhesive deposits occurring in practice is reduced in quantity. This is achieved by the fact that in the accumulator, there are present one or more non-ionic surfactants of a specific structure, the HLB value of which amounts to at least 5. In addition a separator made from filled microporous polyolefins is described, which contains one or more of these surfactants.