Application range of fast-charging in NiCd batteries

In last years, power electronics improvements are allowing designers the use of fast-charging on medium/high capacity batteries. This possibility is very interesting in different applications (communications systems, electric vehicles, low-Earth-orbit spacecraft) in order to minimize charging time. However, a safe fast-charge (without negative effects on battery life) requires to apply the right current rate depending on battery state, operating conditions and so on. Limited information about fast-charge effects on battery performance makes difficult to select the right charging rate in each specific application. This is the reason why a full study of NiCd batteries under fast-charge was developed. In this study, several NiCd batteries (100Ah) were tested intensively at charging rates from 0.1C to 2C, and 23°C of environment temperature. Evolution of main parameters (battery voltage, current and temperature, and hydrogen production) were recorded. Then, data obtained were processed and analysed to determine the effects of fast-charging on NiCd batteries. In this paper, statistic data are used to show main characteristics of charging process as a function of charging rate used. In this way, conclusions about the application range of fast-charging in medium/high capacity NiCd batteries can be reached.