Influence of the Cell Topology, Thermal Conditions and initial Cell to Cell Variances on Aging Gradients among Lithium-Ion Cells of a Battery

Due to the power and energy demand of large-scale applications, like electric vehicles, batteries consists of a high number of single cells connected in serial and parallel. Caused by cell manufacturing induced Cell to Cell Variances (CtCV) as well as system design tolerances in terms of contact resistances and cooling, heterogeneous electrical and thermal loads arise among the cells of a battery. This can lead to aging gradients, which can further increase the initial CtCV, resulting in an accelerated battery degradation. To evaluate the influence of initial CtCV, different thermal conditions of the cells, battery assembly tolerances as well as the cell topology on aging gradients an Equivalent Circuit Model (ECM) is coupled with a thermal and an aging model in this work. The models are implemented in Matlab® and Monte Carlo simulations are conducted to investigate the influences of the mentioned parameters.