Nickel-Metal Hydride Technology- A Solution for Niche Telecom Power Applications

Nickel-metal hydride (Ni-MH) technology is often overlooked by telecom users who are considering advanced battery technologies. The paper details the characteristics of Saft´s large-format Ni-MH technology and provides comparisons with nickel-cadmium, valve-regulated lead-acid and lithium-based batteries. It will be seen that Ni-MH offers a viable solution for certain niche applications in telecom power. One such niche is the emerging application for modular central office (CO) power. The paper describes this application and discusses the results of trials with a large operating company that is beginning to develop modular CO installations. While these large-format Ni-MH batteries are best applied in floating applications with controlled temperatures, this does not mean that Ni-MH electrochemistry is excluded from outside plant applications. Certain legacy digital loop carrier systems with distributed power have long been known to overcharge traditional batteries. Based on the space savings available with the use of high-temperature cylindrical Ni-MH cells, Saft has been able to integrate these cells with an innovative charging and control unit, all in the same space as existing VRLA batteries. This arrangement bypasses the damaging overcharging normally imposed by the installed charger, without affecting the attached loads, and allows the battery to reach its full life expectancy of over 8 years at a continuous operating temperature of 37 degC (100 degF). The last section of this paper describes the components of this battery system. The results of field trials and NEBS testing will also be discussed