NOVELTY - A battery separator (10) comprises a porous polymeric film (20) with a melting point of greater than or equal to 130degreesC coated with a thermally sensitive coating (30) disposed on a surface of the porous polymeric film and a binder comprising a cross-linked adhesive and an adhesion promoter. The coating comprises heat-fusible polymeric particles (40) having a melting point of less than the melting point of the polymeric film.    USE - For an electrochemical cell (claimed), e.g. primary and/or secondary battery, used in large hybrid electric vehicles.    ADVANTAGE - The inventive battery separator can control uncontrolled or undesirable reactions in the electrochemical cell.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (A) a thermally sensitive coating solution for a battery separator, comprising heat-fusible particles, an adhesive comprising a cross-linkable polymer, an adhesion promoter comprising a polar modified polyolefin, and a solvent;    (B) a method of preparing a separator coating solution by dissolving a cross-linkable adhesive in a solvent solution comprising a polar component, a non-polar component and a high boiling point component from diethylene glycol dibutylether and a mixture of aromatics, ketones, and esters and dispersing the heat-fusible material in the solvent solution;    (C) a method of preparing a thermally sensitive separator by:    (1) providing the coating solution comprising a heat-fusible material, an adhesive and an adhesion promoter in a solvent solution comprising a polar component, a non-polar component and a high boiling point component from diethyleneglycol dibutylether and a mixture of aromatics, ketones and esters;    (2) applying the coating solution on a surface of a porous material;    (3) vaporizing a portion of the solvent from the coating solution to coat the surface of the porous material with a thermally sensitive layer comprising the heat-fusible material;    and    (D) a method of coating a separator by preparing a coating solution of heat-fusible materials, an adhesive, an adhesion promoter and a solvent mixture, applying the solution on a surface of the separator and vaporising a portion of the solvent from the coating solution to coat the surface of the separator with a thermally sensitive layer comprising a heat-fusible material; and    (E) an electrochemical cell comprising a separator disposed to electrically separate an anode and a cathode, where the separator comprises a porous polymeric material and a thermally sensitive coating disposed on a surface of the separator, the thermally sensitive coating comprising heat-fusible polymeric particles, an adhesion promoter comprising a polyolefin having at least one pendant hydroxyl, carboxylic and chlorinated functional group, and a cross-linked adhesive.    DESCRIPTION OF DRAWING(S) - The figure is a schematic diagram showing a cross-section of a portion of the inventive separator.    Battery separator (10)    Porous polymeric film (20)    Thermally sensitive coating (30)    Heat-fusible polymeric particles (40)    Cover pores (45)