Abstract: A method for heat treatment of a cold rolled strip with a surface coating of Ni and/or Co and incorporated non-metallic elements C and/or S, if need be with the addition of Fe, In, Pd, Au and/or Bi, whereby the cold rolled strip has a low carbon content. Since the compounds of C, S, N and P deposited on the grain boundaries bring about the most micro-cracks with the surface coating metal if no recrystallization takes place, the temperature of the heat treatment should be selected lower than the recrystallization temperature and higher than the precipitation temperature. With a recrystallization, the grain sizes would easily attain the thickness of the coating so that the embrittled compounds would migrate with the grain boundaries out of the coating. Due to the choice of temperature of the heat treatment of the surface coating of the invention, in contrast, an optimal embrittlement of the grain boundaries is guaranteed, which is especially advantageous in the manufacture of battery cans.

Abstract: A battery sheath made of formed and cold-rolled sheet metal as well as a process for manufacturing the battery sheath are proposed. In the process, cold-rolled strip stock is provided on at least one side with a coating of Ni, Co, Fe, Sn, In, Pd, Bi or their alloys in an electroplating bath, e.g., a Watts-type bath. As an additional component, the electroplating bath contains electrically conductive particles such as carbon, carbon black, graphite, TiS2, TaS2, MoSi2. These particles are deposited on the base material during electroplating together with Ni, Co, Fe, Sn, In, Pd, Bi or their alloys. The sheet metal side with, for example, the carbon-containing electroplated coating faces preferably inwardly when the sheet is formed into a battery sheath. Batteries with battery sheaths produced in this manner exhibit reduced increase in internal resistance, even with prolonged storage, as compared to known batteries.

Abstract: A method for heat treatment of a cold rolled strip with a surface coating of Ni and/or Co and incorporated non-metallic elements C and/or S, if need be with the addition of Fe, In, Pd, Au and/or Bi, whereby the cold rolled strip has a low carbon content. Since the compounds of C, S, N and P deposited on the grain boundaries bring about the most micro-cracks with the surface coating metal if no recrystallization takes place, the temperature of the heat treatment should be selected lower than the recrystallization temperature and higher than the precipitation temperature. With a recrystallization, the grain sizes would easily attain the thickness of the coating so that the embrittled compounds would migrate with the grain boundaries out of the coating. Due to the choice of temperature of the heat treatment of the surface coating of the invention, in contrast, an optimal embrittlement of the grain boundaries is guaranteed, which is especially advantageous in the manufacture of battery cans.