Accurate detection algorithm of battery full-capacity under fast-charge

The expanding number of battery portable products has widely increase the use of sealed NiCd/NiMH batteries. Battery fast-charge (in less than one hour) is very useful but, in fast-charge, cell pressure and temperature increase quickly during overcharging (after the battery reaches full-charge). Usual fast-charge end methods do not avoid the overcharge or they require complex calculation processes. In this paper, a new fast-charge end method is proposed. This method is based on a simple and easily implemented algorithm and it allows us to know accurately and reliably the moment when the battery reaches full-capacity. In this way, a safe fast-charge without negative effects on the effective capacity of the battery and on battery cycle-life is guaranteed.