a battery separator for use in flooded cell type lead acid batteries comprising a backweb of a porous , acid resistant , embossable material with a plurality of ribs extending from at least one planar surface of the backweb . the ribs are located across the width of the backweb and extend in a direction substantially parallel to the longitudinal dimension of the backweb . each rib is an embossed corrugated structure comprised of alternating ridges and furrows . the ridges and furrows are in non - parallel alignment to the longitudinal dimension of the separator , and preferably perpendicular thereto . the ribs are formed on a substantially flat battery separator backweb by passing the backweb through the nip formed by a pair of opposed embossing rollers .