Development of concentrator modules with dome-shaped fresnel lenses and triple-junction concentrator cells

Abstract

The status of the development of a new concentrator module in Japan is discussed based on three arguments, performance, reliability and cost. We have achieved a 26·6% peak uncorrected efficiency from a 7056 cm2 400× module with 36 solar cells connected in series, measured in house. The peak uncorrected efficiencies of the same type of the module with 6 solar cells connected in series and 1176 cm2 area measured by Fraunhofer ISE and NREL are reported as 27·4% and 24·8% respectively. The peak uncorrected efficiency for a 550× and 5445 cm2 module with 20 solar cells connected in series was 28·9% in house. The temperature-corrected efficiency of the 550× module under optimal solar irradiation condition was 31·5 ± 1·7%. In terms of performance, the annual power generation is discussed based on a side-by-side evaluation against a 14% commercial multicrystalline silicon module. For reliability, some new degradation modes inherent to high concentration III-V solar cell system are discussed and a 20-year lifetime under concentrated flux exposure proven. The fail-safe issues concerning the concentrated sunlight are also discussed. Moreover, the overall scenario for the reduction of material cost is discussed. Copyright © 2005 John Wiley & Sons, Ltd.