Ingo Koch

Model simulation and analysis of proton incorporation into the positive active mass of a lead/acid battery: influence of transient and steady-state behavior

In this theoretical work, a mathematical model of the positive active mass of a lead/acid battery considering the effect of proton incorporation into the solid material of the lead dioxide electrode is presented. It can be regarded as an extension of a classic isothermal description, well known from literature. The influence of the proton incorporation reaction on the transient behavior as well as on the steady-state profiles has been analyzed and compared to the classical model. A significant influence of the process of proton incorporation on the transients of the model quantities was found, which reflects a pseudocapacitive behavior of the positive active material. This effect stabilizes the positive electrode potential, especially at a short-time high rate current flow. It could be shown that the transport of protons through the active mass is also present in steady-state conditions. This allows the protons two alternative ways of transportation, liquid and solid phases, in both transient and steady-state situations. Proton transport in the solid phase has not been considered before and may explain the high pseudocapacity of lead dioxide positive active material.