Towards a comprehensive model for the positive electrode system of a lead-acid traction cell : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Production Technology at Massey University
This thesis develops a detailed model for the positive
electrode system of an industrial lead-acid traction cell.
This is referred to as the VIAM model since it relates the
positive electrode voltage (V) and cell current (I) to
internal distributions of current, potential, acid
concentration and active mass (AM). The model can simulate
both discharge and charge for a wide range of practical
currents. The model takes account of microstructure,
macrostructure and non-reactive structure in the positive
active mas (AM). It also takes account of other cell
components that affect the supply of acid to the positive
electrode. The model has direct application to fundamental
cell design (for example AM development) and cell systems
design (for example cell charger design).
The model is based on established experimental
studies, theories of electro chemical interface reactions
and theories of ionic transport in electrolyte solution.
From this base, three elemental models and an aggregate
model are developed. The elemental models represent details
of the microstructure of the positive electrode AM. The
aggregate model represents the electrolyte mass (acid) and
charge transport system within the positive electrode and
other cell components. The combination of the elemental and
aggregate models make up the VIAM model. The performance of
the VIAM model (and underlying models) is assessed by
comparing model results with findings from experimental
studies in the literature. In addition, experiments
undertaken as part of this work are used to test the model.
The model and experimental results are in close agreement.