NOVELTY - Producing a battery case involves providing a strip of first metal having first and second surfaces; providing the strip on the first surface with a second metal layer; providing the strip on the second surface with an electrically insulating polymer layer; and forming a battery case from the strip. The strip first surface is turned to the inside of the battery case and the strip second surface is turned to the outside of the battery case.    USE - The method is used for producing a case for batteries used in portable devices.    ADVANTAGE - The method does not require an additional process step to apply the electrically insulating layer. It minimizes the possibility of counterfeiting the identification of the brand or producer of the battery after it has been produced. It reduces increase in thickness as a result of the electrically insulating layer. The produced battery case shows excellent adhesion of the polymer layer to the metal strip before and after forming the battery case.    DETAILED DESCRIPTION - Producing a battery case involves providing a strip of a first metal having a first surface and a second surface; providing the strip on the first surface with a layer of a second metal; providing the strip on the second surface with an electrically insulating polymer layer; and forming a battery case from the strip in one or more forming steps. The battery case has an inner surface and an outer surface. The first surface of the strip is turned to the inside of the battery case and the second surface of the strip is turned to the outside of the battery case. An INDEPENDENT CLAIM is also included for producing a strip comprising:    (A) producing a first metal strip having a first surface and a second surface;    (B) providing the strip with a layer of a second metal on the first surface, preferably where the second metal consists of nickel;    (C) performing recrystallization annealing of the strip;    (D) coating the strip on the second surface with an electrically insulating polymer layer, preferably comprising PET and/or PP, preferably by coextrusion or laminating rolling so as to be able to produce battery cases.