The cell barrier for a rechargeable battery module of the present invention includes a metal body and an insulating layer disposed on the surface of the metal body. The cell barrier is interposed between unit cells to electrically insulate between the unit cells. The insulating layer is selected from the group consisting of a resin layer, an inorganic oxide layer, an anodized layer, and a composite layer thereof. The cell barrier also has channels to provide for additional cooling by a heat transfer medium. A single unit cell can also be used with a cell barrier disposed along the unit cell for insulation and cooling.