Vehicles with a combustion engine as well as electric driven
vehicles, electric or hybrid cars) use batteries with serial
connected cells. For a reliable function a monitoring device
observe the state of the batteries. For lead acid batteries this
is done by measuring voltage and current on the outer battery
clamps [19]. By this measurement only an averaged state
of the cells can be predicted. By manufacturing tolerances
and slightly different environment influences cells can develop
small charge differences. These differences grow by cyclic use
of the battery over time. The weaker cells will be more stressed
and degraded in capacity and health. So the battery durability
is limited by the weakest cell. Hence it is useful to monitor
each battery cell individual.