Three-Dimensional Performance and Lifetime Model for Lithium-Ion Batteries - Spatially-Resolved Models are Required for Accurate Simulation of Large-Sized Cells!

摘要

Performance, safety and lifetime of Li-ion batteries are closely connected topics, which are strongly influenced by electrical and thermal inhomogeneities occurring during operation inside the system. These inhomogeneities might impact large-sized automotive cells over complete life cycles significantly; however current lifetime models are not able to consider these effects. This work introduces a new spatially-resolved lifetime modeling concept for Li-ion batteries consisting of a spatially-resolved thermo-electrical model and a semi-empirical ageing model for more accurate performance and lifetime simulation of large-sized cells. Simulations carried out for cylindrical cell types show significant thermal and electrical gradients between inner and outer cell, which force a strongly inhomogeneous degradation of the cell's active mass. This yields a redistribution of currents and impedance with increasing lifetime. Lifetime prognosis carried out on the new modeling approach points out its advantages for large-sized cell simulation towards conventional one-node models.