Pareto-Optimal Design of Automotive Battery Systems with Tabless Cylindrical Lithium-Ion Cells: Resolving the Trade-Off Between Energy, Performance, Weight, and Cost for Variable Vehicle Requirements

Abstract

Large-format tabless cylindrical cells have been a top research subject within recent years. However, research so far has exclusively focused on isolated understanding of individual aspects such as the performance, safety, or cost. This study introduces a global optimization framework for battery systems with tabless cylindrical cells based on the groundwork laid within recent years. The framework is applied to gain comprehensive understanding of cross interactions between different design variables and the key performance indicators of the battery system. It was found that a well-defined diameter exists which optimizes the battery energy for given boundary conditions. The multiobjective trade-off between energy, performance, weight, and cost however might lead to different solutions with respect to the desired properties of the system. Small cylindrical cells with diameter less than 25 mm provide enhanced performance but lower energy and higher cost. Very large cylindrical cells with diameter more than 50 mm have less options for interconnection but provide the best cost-saving potential. With realistic constraints, only diameters larger than 40 mm achieve Pareto-optimal solutions. Aluminum housings are found to outmatch steel housings in nearly all properties, especially for larger diameters. Considering the widespread introduction of aluminum housings is recommended for automotive manufacturers.