Capacity Estimation and Lifetime Expectancy of Large-Scale Nickel Metal Hydride Backup Batteries

Conference: Intelec '05 - Telecommunications Conference - 27th International Telecommunication Energy Conference
09/18/2005 - 09/22/2005 at Berlin, Germany

Proceedings: Intelec '05 - Telecommunications Conference

Pages: 5Language: englishTyp: PDF

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Yamashita, Akira; Wakaki, Hiroshi; Saito, Keiichi; Shodai, Takahisa (NTT Corporation, Atsugi, Japan)

We estimated the capacity and life expectancy of 100-Ah-scale large nickel metal hydride backup batteries. The proposed method is based on the correlation between the voltage drop after charge cessation and the capacity of degraded batteries. The magnitude of the voltage drop varies with the environmental temperature, but a method of offsetting this temperature dependence is described. Capacity estimation is now possible under the environmental temperature between 0deg C and 50deg C.