Using a pulse-current technique and measured resistance to evaluate the capacity of trickle-charged nickel/cadmium cells

The use of a pulse-current technique to evaluate the capacity of trickle-charged nickel/cadmium (Ni/Cd) cells is investigated. A current pulse is applied to the cells in the charging mode and the resistance is estimated from the change in voltage. A linear relationship between the capacity and the logarithm of the resistance is observed. The combination of a pulse current of 0.1–1.0 C and a pulse width of 10 ms or less displays a high correlation coefficient for deteriorated cells. The error between the evaluated and the measured capacity is less than 10%, on average, under these conditions in the capacity range of greater than 50% nominal capacity.