Physical Modelling of the Slow Voltage Relaxation Phenomenon in Lithium-Ion Batteries

In the lithium-ion battery literature, discharges followed by a relaxation to equilibrium are frequently used validate models and their parametrizations. Good agreement with experiment during discharge is possible using pseudo-two-dimensional model such as Doyle-Fuller-Newman (DFN) model. The portion, however, typically not well-reproduced, in experiments occurring much more slowly than models. this study, that includes size distribution of active material particles, we give physical explanation for slow phenomenon. This model, Many-Particle-DFN (MP-DFN), compared against data from optimal fits parameters (mean variance), well solid-state diffusivities, found numerical optimization. voltage after captured careful choice current cutoff time, allowing single set be all C-rates, contrast previous studies. We find MP-DFN can accurately reproduce relaxation, across range whereas DFN cannot. Size distributions allow greater internal heterogeneities, giving natural origin slower timescales may relevant other, yet explained, behavior.