Life cycle testing of spaceflight qualified nickel-hydrogen battery cells

The nickel-hydrogen (Ni-H₂) aerospace battery has become the advanced power storage system of choice for military and commercial satellite programs requiring high reliability, long-life and rugged, abuse-tolerant operation. This system is providing dependable eclipse and peak power to hundreds of Earth orbiting satellites as well as planetary spacecraft. These batteries have provided in excess of two hundred million successful operational cell-hours on-orbit. Due to the nature of the application, battery failure is not an option, therefore quality performance is of the utmost importance. In addition to the system´s extensive flight proven heritage, Ni-H₂ batteries and battery cells have been subjected to many and varied life cycle tests. Both real-time (RT) and accelerated (ACC) tests in Low Earth Orbit (LEO) as well as Geosynchronous Orbit (GEO) test regimes have been performed and are represented. In some cases, these tests attempt to duplicate the on-orbit charge/discharge profile of the application as closely as possible, as well as testing extreme situations. This test database was originated in support of early Ni-H₂ flight programs and has been consistently expanded over 15 years. In addition to the testing performed in-house, many life cycle tests are performed by our customer base as well as independent test laboratories. Several different Ni-H₂ cell and battery designs are on test including Individual Pressure Vessel, Common Pressure Vessel, Single Pressure Vessel and Dependent Pressure Vessel