Modeling Battery Performance Due to Intercalation Driven Volume Change in Porous Electrodes

Abstract

A mathematical battery model is presented that incorporates the dimensional and porosity changes in porous electrodes caused by volume changes in the active material during intercalation. Porosity and dimensional changes in an electrode can significantly affect the resistance of the battery during cycling. In addition, volume changes generate stresses in the electrode, which can lead to premature failure of the battery. Here, material conservation equations are coupled with the mechanical properties of porous electrodes to link dimensional and porosity changes to stresses and the resulting resistances that occur during the intercalation processes. The stress-strain relationships used in this model are from previous works, which are used to predict porosity and dimensional changes, and were established by comparing thermal rock expansion and electrode expansion due to intercalation. Several different battery casings are examined and operating curves are predicted based off of standard equilibrium potentials combined with simple kinetics.