A nonwoven composite web suitable for use, after post-treatment with a wetting agent, as a battery separator is formed by a wet process on a papermaking machine. One nonwoven composite material is made from a furnish of polyolefin binder fibers and polyolefin staple fibers. The web coming off the papermaking machine is dried using infra-red dryers followed by heated dryer cans. After drying, the web is thermally bonded using heated calendar rolls. The polyolefin binder fibers melt as the web passes through the calendar rolls and thermally bond the polyolefin staple fibers of the web when the melted binder fiber material fuses upon cooling.