Nickel-hydrogen and lithium-ion aerospace battery technology life test update

Abstract

Eagle-Picher Tkchnologies (EPT) nickel-hydrogen batteries and battery cells have been subjected to many and varied life cycle tests. Both real time and accelerated tests in Low Earth Orbit as well as Geosynchronous Orbit test regimes have been performed. In most cases, these tests attempt to represent the on-orbit charge/discharge profile of the application as closely as possible, as well as test for extreme conditions. This test database was originated in support of early nickel-hydrogen flight programs and has been consistently expanded over the past fifteen years. Several different nickel-hydrogen cell and battery designs are on test including Independent Pressure Vessel , Common Pressure Vessel , Single Pressure Vessel , and Dependent Pressure Vessel. EPT’s lithium-ion technology development began in 1995. Initial life cycling was performed at a high discharge rate and depth-ofdischarge to stress the system and reduce test time. Later testing incorporated lower depth of discharge and GE0 test regimes in order to provide a data base for comparison to the more mature nickel-hydrogen technology.