Saft is working on a collaborative project with its partners in Russia to develop and flight test the world’s first hybrid lithium battery system for a new generation of light-class launch vehicles. This development is fully supported both by CNES (French space agency) and Roscosmos (the Russian Federal Space Agency), and continues Saft’s long term cooperation with Russian partners in the space industry.
The prototype hybrid battery will combine primary lithium cells and rechargeable lithium-ion (Li-ion) cells in an integrated, fully autonomous power supply unit from Saft and completed with control systems from FSUE RISDE. This novel approach will offer a number of operational advantages for both the launcher and upper stage, including longer mission-life, increased capacity in a smaller footprint and greater current capability.
Hybrid advantages
The prototype hybrid battery is based on a modular concept that combines two of Saft’s space-proven cell technologies – primary lithium cells and rechargeable Li-ion cells – to deliver high electrical and thermal performance at temperatures from -20°C to +70°C. This approach effectively offers the best of both worlds: the instant power capability of the Li-ion cells ensures voltage stability by eliminating the delay effect sometimes experienced with primary lithium cells; the Li-ion cells can deliver high peak pulse currents of up to 50 A for several minutes.
A further advantage of the hybrid battery is that the primary cells provide a fully autonomous charging current for the Li-ion cells. So for example if the battery is discharged during launch vehicle integration tests it can be recharged for the actual launch, with no need to connect an external charging supply. The primary cells will make it possible to maintain the battery capacity for longer mission times, as well as providing extended storage times of three months on the launcher and a minimum of one year on the ground.
The prototype Saft hybrid battery is expected to make its first space flight by the end of 2011. It will be integrated in the Photon spacecraft manufactured by Samara Space Center as experimental equipment.