Space Borne Solar Generators Towards Flexible Solar Cell Assemblies: Actual Status and Future Development Strategies

Paper number

IAC-08.C3.2.3

Author

Mr. Emanuele Ferrando, Galileo Avionica S.p.A., Italy

Coauthor

Mrs. Roberta Campesato, CESI, Italy

Coauthor

Mrs. Maria Cristina Casale, CESI, Italy

Coauthor

Mrs. Raffaella Contini, Galileo Avionica S.p.A., Italy

Coauthor

Mr. Romano Romani, Galileo Avionica S.p.A., Italy

Year

2008

Abstract

The likeliest evolution of the space borne solar cell assemblies is towards thinner and lighter structures, capable to be used in combination with solar generator systems having a reduced volume at launch, combined with outstanding electrical performances.
State of the art GaAs based triple junction solar cells are the baseline building block for the majority of the nowadays applications and so they are the reference for any alternative solar generating system giving also a sort of access barrier and reference for any further technology developments.
Starting from that, Galileo Avionica and CESI initiated, under an Italian Space Agency (ASI) contract, a development program finalized to “flexible” photovoltaic assemblies. In the frame of this activity two cell technologies were considered: CIGS growth on thin metal substrate and GaAs triple junction growth on thin (80 ?m) Ge wafers. This trade off was focused on a set of performance indicators like the end of life electrical performance, the maximum allowable bend radius and the compatibility with the existing integration processes like joining, glassing (or any other protection means) and structural bonding.
Preliminary results from the “ground” characterization campaign have been collected and the correspondent technological readiness level assessed. The main achievements were the demonstration of the extremely good bending properties of the thin crystalline triple junction cells in combination with conversion efficiencies perfectly aligned with the state of the art “thick” ones.
Based on the above results and having in mind the future perspectives, we also continued the exploration of the mid and long term scenarios.
The future perspectives on  the triple junction development trend towards an ultra thin design based on the epitaxial lift off technology in combination with further gain in conversion efficiencies,  allow the conclusion that the trade off for missions not exceeding a long lasting GEO equivalent environment is again in favour of the III-V compounds based solar cells

Abstract document

IAC-08.C3.2.3.pdf

Manuscript document

IAC-08.C3.2.3.pdf (🔒 authorized access only).

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