Abuse Simulation of Battery Packs based on the Testing of Single Battery Cells

Summary:

According to several standards and regulations, battery packs must pass certain tests with respect to their abuse behavior. Especially, the thermal propagation, induced by one cell and resulting in a catastrophic failure of the whole pack, is hereby addressed and must be impeded by constructional measures. Within the relating design process, simulations of the applied battery cells and their interactions can massively contribute to an efficient optimization of the batteries system’s overall safety behavior. With this motivation, the abuse simulation of a multi-cell mockup based on the simulation and testing of a single battery cell is presented in this lecture. At first, a multi-physical simulation model of a cylindrical cell is created. To this end, a self-developed automated generation methodology for the commercial finite element code LS DYNA is utilized. The according thermal and electrical parameters are identified from experimental results of an electrical characterization as well as of an overheat test. Due to the evaluation of an overheat test, the arise of an internal short circuit as well as the thermal runaway can also be characterized and simulated. Afterwards, the validated model of the single battery cell is applied in a simulation of an overheat test of a multi-cell mockup. The investigated multi-cell mockup consists of seven battery cells in a hexagonal arrangement. Within the test, the center cell is overheated and a thermal runaway, which leads to a thermal propagation, is initiated. The simulative data are compared to data, resulting from an experimental execution of this test. The good accordance of the data proof the applicability of the resulting models as well as of the model generation methodology.