Light Weight Nickel-Alkaline Cells Using Fiber Electrodes 2004-01-3167

Using a new fiber electrode technology, currently developed and produced by Bekaert Corporation (Bekaert), Electro Energy, Inc., (EEI) Mobile Energy Products Group (formerly, Eagle-Picher Technologies, LLC, Power Systems Department) in Colorado Springs, CO has demonstrated that it is feasible to manufacture flight weight nickel hydrogen cells having about twice the specific energy (80 vs. 40 watt-hr./kg) as state-of-the-art nickel hydrogen cells that are currently flown on geosynchronous communications satellites. Although lithium-ion battery technology has made large in-roads to replace the nickel alkaline technology (nickel-cadmium, nickel-metal hydride), the technology offered here competes with lithium-ion weight and offers alternatives not present in the lithium-ion chemistry such as: ability to undergo a continuous overcharge, reversal on discharge, and sustain rate capability sufficient to start automotive and aircraft engines at subzero temperatures.

In development to date seven 50 ampere-hour nickel-hydrogen cells have been constructed, acceptance tested and briefly analyzed in a low earth orbit (LEO) cycle regime. The effort was jointly funded by Electro Energy, Inc. and NASA Glenn Research Center, Cleveland, OH. Five of the seven cells have been shipped to NASA GRC for further cycle testing. Two of the cells experienced failure due to internal short circuits during initial cycle testing at EEI. Destructive Physical Analysis (DPA) of both cells has shown the failure mode to be due to inadequate hydrogen catalyst electrodes that were not capacity balanced with the higher energy density nickel oxide electrodes. In the investigators' opinion, rebuild of the cells using proper electrode balance would result in cells that could sustain over 30,000 cycles at moderate depths of discharge in a LEO regime, or endure over 20 years of geosynchronous orbit (GEO) cycling while realizing a two fold increase in specific energy for the battery or a 1.1 kg weight savings per 50 ampere-hour cell.

It is concluded that continued development of light weight, fiber electrode nickel alkaline batteries, including: nickel-hydrogen, nickel-metal hydride, nickel-cadmium and nickel zinc couples, for USAF and NASA spacecraft, USAF and USN aircraft applications, USN underwater utility vehicles, USA 21^st Century Warrior support and other DOD efforts will result in improved battery systems for NASA, DOD and the Warfighter.