Separators for vrla batteries and methods relating thereto

A battery separator comprising:

• at least one microporous polyolefin separator layer, said microporous polyolefin separator layer having a first surface and a second surface;
• at least said first surface comprising at least one of the list consisting of ribs, embossments, acid filling channels, and a combination thereof;
• at least said second surface comprising at least one of the list consisting of ribs, embossments, acid filling channels, mini cross ribs, and a combination thereof;
• said microporous polyolefin separator layer comprises first areas comprising a first set of pores and a compressed pore structure;
• and further comprises second areas comprising a second set of pores and a pore structure less compressed than the pore structure of the first areas;
• and,
• wherein said embossments are textured embossments, straight pattern embossments, wavy pattern embossments, embossments in a picture pattern, zigzag pattern embossments, or a combination thereof.

A composite battery separator comprising:

• at least one microporous polyolefin separator layer, said microporous polyolefin separator layer having a first surface and a second surface;
• at least said first surface comprising at least one feature selected from the group consisting of ribs, embossments, acid filling channels, and a combination thereof;
• at least said second surface comprising at least one feature selected from the group consisting of ribs, embossments, acid filling channels, mini cross ribs, and a combination thereof;
• said microporous polyolefin separator layer comprises first areas comprising a first set of pores and a compressed pore structure;
• and further comprises second areas comprising a second set of pores and a pore structure less compressed than the pore structure of the first areas;
• and
• at least one first mat or nonwoven layer adjacent to one of said first surface or said second surface, and wherein said feature is adjacent said first mat or nonwoven layer.