LAUSR

Abstract This study was inspired by the experimental observation that the battery resistance under dynamic loading is larger than that in the quasi-static loading. To clarify the underlying mechanism, control tests comparing the compressive responses of dry and wet battery samples were carried out under five loading speeds. Test results showed a clear strengthening of the resistance of the wet samples while the behavior of dry samples was almost identical under increasing loading speeds. This means that the strain rate effect of the wet cells largely comes from the electrolyte. To quantify this effect and model the overall mechanical behavior, a poromechanical model utilizing Darcy's law to characterize the pressure gradient and velocity of electrolyte was established, and the Kozeny–Carman equation was used to determine the permeability of the porous media of the cell. The prediction of the model with the assumption of planar flow agreed well with the experimental results of uniaxial compression. Furthermore, a detailed finite element model of the multi-layered structure of battery cell was established in Abaqus in which separator, current collector, and coatings of electrodes were all modeled as individual components. Simulation results clearly showed the influence of electrolyte on the dynamic response of battery cells.