integrated li-ion cells/super-capacitors modular battery system

Paper number

IAC-08.C3.2.9

Author

Ms. Gaia Fusco, Carlo Gavazzi Space S.p.A., Italy

Coauthor

Dr. Massimiliano Pastena, Carlo Gavazzi Space S.p.A., Italy

Coauthor

Prof. Marco D'Errico, Seconda Universita' di Napoli, Italy

Year

2008

Abstract

Answering to a growing demand of lower cost, re-usable and flexible space architectures, Carlo Gavazzi Space S.p.A. (CGS) has developed modular components for space applications including a Li-ion battery.
The first battery system configuration developed by CGS integrates n cell modules (each including eight Li-ion cells) and a single balancing/bypass electronics module. Such modular battery can satisfy a large number of power requirements for different satellite configurations by simply adding or removing modules, i.e. it does not need to be re-designed and re-qualified for each mission, minimizing development times and costs.
In recent times, answering to the future spacecrafts need of lower cost long-lived battery systems able to provide bursts of high power, such initial CGS modular battery design has been improved integrating high power density super-capacitors able to support Li-ion cells during peak power requests and protect cells from high DODs.  This design modification optimizes power supply of satellite equipments requiring very high power for short times (such as SAR, reaction wheel and S-band transmitter) and increases battery lifetime.     

In order to analyze, prevent, and manage critical aspects such as unbalancing of series-connected cells and parallel-connected modules, cells aging and temperature effects, battery design claimed for an accurate prediction of cells behaviour during charge and discharge. To this end, an accurate Li-ion cell mathematical model was developed and validated by CGS to assist battery design with appropriate simulation tools.
CGS battery system design modifications due to the integration of super-capacitors, have requested the development of an equally accurate super-capacitor mathematical model and a battery system simulation tool improvement.     

This paper is focused on the description of super-capacitor electrical model and CGS battery simulation tool upgrading. Three main modular battery system simulations have been performed. The first one is carried out on the CGS initial modular battery configuration (without super-capacitors). The second one describes super-capacitors behaviour in case of peak power requests (excluding battery cells). The third simulation is carried out on the complete battery system composed of battery cells and super-capacitors. Simulations purpose consists in highlighting advantages, identifying and managing design critical aspects of the integrated modular battery, such as compatibility and simultaneous use of cells and super-capacitors. Simulation results highlight integrated battery system design potentialities and peculiarities, verifying that super-capacitors are able supply the required energy in case of peak power requests without increasing battery cells DOD and assessing battery lifetime increase due to the integration of super-capacitors. 

Abstract document

IAC-08.C3.2.9.pdf

Manuscript document

IAC-08.C3.2.9.pdf (🔒 authorized access only).

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