Internal short circuits in automotive lead batteries for safety applications, Part 1: robustness of batteries

Future vehicle applications will take advantage of the robustness of lead batteries. However, possible concerns are sudden failures like the detrimental effects of internal short circuits and their impact on battery performance and life-time. In laboratory experiments in cooperation with Bosch, Clarios was able to intentionally create short circuits in lead batteries, determine their ohmic resistance and to perform further laboratory tests with artificial short circuits, which can be switched on and off externally. With this setup, we were able to closely track battery performance during and after removal of a simulated short circuit in a battery cell. Finally, the battery voltage did not drop suddenly, but in a time frame of several days to weeks. This large window is based on the robustness of the lead battery system and allows defective parts to be replaced before the performance loss becomes critical for vehicle safety applications. Additionally, the battery was able to substantially recover after the artificial short-circuit was removed. In this first part of the presentation, experimental data will be provided, complemented by the battery power prediction approach presented by Bosch in the second part of the presentation.