Abstract: The invention relates to a separator film for a device used for storing electrical energy, the film being porous and oriented, and being obtained by stretching in a longitudinal direction and in a direction transverse to the longitudinal direction, the film containing a mixture comprising a polypropylene homopolymer, at least 10% of a copolymer obtained from monomers comprising at least propylene and ethylene, and at least one beta-nucleating agent. According to the invention, the ethylene content of the copolymer is ?1% but <10% and a propylene content of the copolymer is ?90% for a film thickness of ?8 microns and ?30 microns, corresponding to a specified space factor according to the IEC-60674-3-1 standard greater than or equal to 145% and a density of the biaxially stretched film greater than or equal to 0.18 g/cm3 but less than or equal to 0.41 g/cm3.

Abstract: A metallized polypropylene film that has a modulus of elasticity in bending higher than 1500 MPa, a sag point under load higher than 110.degree. C., and a Vicat point higher than 150.degree. C. The metallized film is a film for making a capacitor.