摘要 |
A four-stage charging technique for nickel-zinc cells and batteries, is provided, whereby a high cycle life is assured, without dendrite formation or harmful overchange, with minimal shape change of the zinc electrode, and with minimal oxygen, recombination. In the first stage, the nickel-zinc cell or battery is charged with an average current less than C/5 for a period for less than five minutes, or until the terminal voltage of a cell reaches 1.75 volts to 1.79 volts. In the second stage, a fast charge is imposed, until the terminal voltage of a cells reaches between 1.88 volts and 1.92 volts. In the third stage, a moderate charge is imposed, until the terminal voltage of a cell reaches 1.90 volts to 1.94 volts. The forth stage gives a trickle charge when the terminal voltage is greater then 1.94 volts. Typically, each of the transitions between the Stages 1 and 2 and Stages 2 and 3 is determined by a temperature dependent voltage; the transition between Stages 3 and 4 is determined by a time dependent inflection point of the terminal voltage of the cell; and Stage 4 termination is determined when dV/dt=0. |