Abstract: An integrated cell separator adapted for use with one or more battery cells. The separator includes a thermal isolation/flame-resistant layer and a compliant layer. The compliant layer is adjacent to the thermal/isolation/flame resistant layer. The thermal isolation/flame-resistant layer and the compliant layer are adhered to each other, the compliant layer is adapted to contact the one or more battery cells, and the separator is adapted to provide thermal runaway isolation of the one or more battery cells. A method for separating one or more battery cells.