PRE-CERTIFICATION OF
® HSUN
MODULE ACCORDING TO IEC 62108
Sebastião Coelho1, Bruna Cardoso1,2, Luís Pina1, Nuno Pereira3 and Stanimir Valtchev2 1 – WS Energia S.A., Taguspark, Edífcio Tecnologia II, 46 2740 - 257 Porto Salvo, Portugal (e-mail:
[email protected],
[email protected]) 2 – Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus da Caparica, Monte da Caparica, 2829-516 Caparica (e-mail:
[email protected],
[email protected]) 3 - Lógica - E.M., Parque Tecnológico de Moura, Apartado 87, 7860-999, Moura, Portugal (e-mail:
[email protected])
INTRODUCTION • This paper proposes a pre-certification method (Figure 1) to decrease the time from prototype to certification of a CPV module. • The proposed methodology is applied to the WS Energia’s CPV module HSUN®.
Mechanical Load and Hail Impact: • The parabolic trough presents deformations at 500 Pa (Figure 5)..
visible
Figure 5 – Parabolic trough of the HSUN®, after mechanical load test.
IMPROVEMENTS AFTER THE RE-DESIGN: Figure 1 – Proposed general methodology to certify of HSUN®. ® HSUN
TECHNOLOGY
• HSUN® [1] (Figure 2) is a 20x concentrating system using high efficiency Silicon solar cells. It consists of seven integrated parabolic troughs combined with coupled reflective secondary optics. • The photovoltaic (PV) receiver is attached to the backside of each parabolic mirror, increasing thermal dissipation.
Figure 3 – Three day crash test sequence.
RESULTS Damp Heat: • Loss of performance of 51.1%. • Bubbles between the encapsulant and the secondary optics. • Adhesive yellowing. Thermal Cycling: • Delamination between the solar cells and the encapsulant (Figure 4a). • Broken cells near the welding point due to material thermal expansion (Figure 4b). • Loss of performance of 45.8%.
(a)
Figure 2 – Photograph of HSUN® technology, in WS Energia S.A. laboratory, in Portugal.
CRASH TEST PROCEDURE
EXPERIMENTAL
• Figure 3 presents the crash test sequence applied to HSUN®. The methodology is specially focused in thermal and mechanical tests in order to identify the major defects (design, materials and manufacturing process).
• Reinforcement of the HSUN® sctructure. • Improvement of the soldering process to avoid thermal expansions. • Change of the adhesive materials. • Secondary optics re-design. • Improvement of the encapsulation process. HSUN® was submitted to a second crash test after the re-design. At this moment it is able to advance to pre-certification phase.
PRE-CERTIFICATION EXPERIMENTAL PROCEDURE • Figure 6 shows the pre-certification test sequence with a proposed 1 month duration.
(b)
Figure 4 – a) Delamination spot after 10 thermal cycles. b) Broken cells, detected using electroluminescence technique. Ultraviolet Conditioning test: • Adhesive yellowing. • The encapsulant and the other materials did not present any detectable defect. • Loss of performance of 1%.
CONCLUSIONS • The very aggressive testing procedures of both the three days crash test and the one month pre-certification test provide a very good insight on the outcome of the actual certification process. • The time to market of CPV products can be greatly reduced using a crash & pre-certification procedure before entering the costly and time consuming certification process.
Figure 6 – One month pre-certification sequence[2].
ACKNOWLEDGMENTS The authors gratefully acknowledge partial funding from QREN and Programa Operational da Região de Lisboa and also partial funding of Fundo Europeu de Desenvolvimento Regional (FEDR).
REFERENCES [1] J. Mendes Lopes, L. Pina, F. Reis, S. Coelho, J. Wemans, G. Sorasio, “On-field demonstration results of medium concentration system HSUN®”. Abstract accepted at the CPV-7 conference, April 2011, Las Vegas, USA. [2] J. Wohlgemuth and S. Kurtz, “Reliability Testing Beyond Qualification as a Key Component in Photovoltaic’s Progress Toward Grid Parity”, National Renewable Energy Laboratory,April 2011.
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