Title :
Long-life nickel-metal hydride batteries as a backup power supply for optical fiber networks
Author :
Hirai, Toshiro ; Shikano, Yukiyasu ; Asakura, Kaoru ; Shimomura, Makoto ; Hasui, Harumi ; Yamada, Ichiro
Author_Institution :
NTT Telecommon. Energy Labs., Japan
Abstract :
The authors have developed a nickel-metal hydride (Ni/MH) battery that has a lifetime of eight years at 30°C and operates at temperatures from -10°C to 55°C. This performance was achieved by improving the Ni/MH cells and optimizing their charging. Optimizing the metal-hydride and electrolyte contents of the Ni/MH cells extended cell lifetime from one to two years. Use of an intermittent current-pulse charging method that inhibits cell degradation due to overcharging extended cell lifetime to three times that of cells charged using trickle-charging. Use of an optimum intermittent charging condition allows four batteries to be charged sufficiently at the current needed to fully charge only one battery. This battery has been used as the backup power source in optical network units (ONUs) of Fiber-To-The-Home (FTTH) networks and in the HUB power supplies of Fiber-To-The-Pole (FTTP) networks
Keywords :
electrochemistry; electrolytes; nickel; optical fibre subscriber loops; secondary cells; telecommunication power supplies; -10 to 55 C; 30 C; 8 y; Fiber-To-The-Home networks; Fiber-To-The-Pole networks; HUB power supplies; Ni-MH secondary cells; backup power supply; battery lifetime; electrolyte contents; intermittent current-pulse charging method; optical fiber networks; Batteries; Electronic mail; Emergency power supplies; Laboratories; Optical fiber cables; Optical fiber networks; Optical fiber subscriber loops; Optical network units; Power supplies; Temperature distribution;
Conference_Titel :
Telecommunications Energy Conference, 2000. INTELEC. Twenty-second International
Conference_Location :
Phoenix, AZ
Print_ISBN :
0-7803-6407-4
DOI :
10.1109/INTLEC.2000.884242
