Saft space-qualified MP Li-ion batteries will power the AGILE LEO satellite

Citation

(2007), "Saft space-qualified MP Li-ion batteries will power the AGILE LEO satellite", Aircraft Engineering and Aerospace Technology, Vol. 79 No. 5. https://doi.org/10.1108/aeat.2007.12779ead.021

Saft space-qualified MP Li-ion batteries will power the AGILE LEO satellite

Saft space-qualified MP Li-ion batteries will power the AGILE LEO satellite

AGILE, the Italian Space Agency's high-energy astrophysics mission, launched recently by a PSLV rocket from the Sriharikota base in India, is the first LEO (Low Earth Orbit) satellite to be powered by Saft's commercially available space-qualified MP 176065 rechargeable lithium-ion (Li-ion) batteries. AGILE's near equatorial orbit, at a distance of 550km from the Earth is a particularly demanding application for the on-board battery system, as it will be charged and discharged over a constantly repeating 100min cycle, with no rest periods, throughout a two-year mission.

AGILE is based on a MITA class enhanced platform provided by CGS (Carlo Gavazzi Space S.p.A.) as the leading contractor working in partnership with Oerlikon-Contraves Space, Alcatel-Alenia Space, and Telespazio.

“The successful launch of AGILE with our space-qualified MP Li-ion cells is an important breakthrough for Saft within the LEO market as it confirms our capability to use these standard, commercially available modules to deliver very cost-effective on-board battery solutions that ensure the performance and reliability of the satellite's secondary power supply.” Philippe Jehanno, General Manager of Saft's Space and Defense Division.

AGILE is the only European mission entirely devoted to high-energy astrophysics studies. It will operate as a gamma ray and hard X-ray observatory to survey the celestial sphere and to identify gamma ray bursts and unidentified galactic sources, diffuse galactic and extragalactic gamma-ray emissions.

The Saft battery system will work in conjunction with AGILE's solar array to provide the electrical power for the satellite's on-board electronics, ranging from 200W up to a peak load of 460W. When the solar array is fully exposed to the sun it will provide the satellite's power as well as charging the batteries. When the solar array is “eclipsed” by the earth, with no direct sunlight, the batteries will power the satellite. This charge and discharge cycle will be repeated approximately every 90min – the time AGILE takes to complete one Earth orbit.

The battery system comprises 24 Saft MP 176065 space-qualified Li-ion cells in an eight series and three parallel configuration with a nominal capacity of 16.8Ah and an energy storage capability of 480Wh. An integral autonomous cell balancing system will ensure the maximum possible battery life. Two battery packs with a total number of 48 cells are integrated on board.

The MP 1706065 space-qualified cell is based on Saft's MP series of prismatic rechargeable lithium-ion batteries It claims an extremely high capacity made possible by the stainless steel prismatic container that makes use of the volume lost when conventional cylindrical cells are packed together – a single prismatic cell reportedly has some 20 percent higher volumetric energy density than an equivalent pack of cylindrical cells. Saft's lithium-ion electrochemistry uses cobalt-base and graphite active materials, combined with an innovative organic solvent mix for the electrolyte.

Details available from: Saft, Tel: +33 1 49 93 19 18, E-mail: antoine.brenier@saftbatteries.com