The data of Cugnet et al.[2] are selected for simulation. The
electrode parameters are listed inTable 1. Theoretical capacities of
the electrodes are easily calculated from their dimensions and
porosity, and are found to be greater than the acid capacity. As
mentioned earlier,Qnom ¼rcQtheo, and not Qtheo, determine the
stoichiometric balance.rcis calculated for both the electrodes using
eq.(1), and even Qnomare found to be greater than the capacity of
the acid. However, their data at a very small discharge rate of C/20
show that the discharge halts when only 80% of the acid has been
consumed. Further, their calculations show that both concentration
and porosity are spatially uniform at this low current density.
Hence, some feature exists that makes electrodes the limiting reactants. Following Metzendorf's[1] hypothesis that battery stops
discharging oncercis reached, it may be surmised that some nonconducting inert material is present in electrodes that further reducesrc, or equivalently, the nominal capacity of the electrodes. The
volume fraction of inerts can be estimated as follows. The value of
critical conversion in the presence of inert materials is obtained
from eq.(2)and is given by