AN417 Datasheet, PDF (7/21 Pages) STMicroelectronics – From nickel-cadmium to nickel-hydride fast battery charger

AN417
Charge termination methods
2.2
The inflexion point method
A second charge termination method much more adapted to NiMH batteries consists of
detecting the inflexion point of the voltage curve, thus avoiding any excessive overheating of
the battery. This method therefore significantly increases the battery life-time.
Figure 3. Fast charge terminates at point B in the inflexion point method
V
cell voltage
1.6
1.5
temperature
A
deg C
60
B
50
1.4
battery voltage
40
1.3
battery temperature
1.2
charging time
30
20
-36
Doc ID 2074 Rev 2
7/21