Development of a new 550X concentrator module with 3J cells - Peformance and reliability

The status of the development of a new concentrator module in Japan is discussed based on three arguments, performance, reliability and cost. The peak uncorrected efficiency for a 7,056 cm² 400 X module with 36 solar cells connected in series was 26.6 % was measured in house. The peak uncorrected efficiencies of the same type of the module with 6 solar cells connected in series and 1,176 cm² area measured by Fraunhofer ISE and NREL were 27.4 % and 24.8 % respectively. The peak uncorrected efficiency for a 550X and 5,445 cm² module with 20 solar cells connected in series was 28.9 %. The temperature corrected efficiency under the best sunshine condition in Japan for the 550X module was 31.5 ±2 %. 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 of the concentrated sunlight are also discussed. For cost, the overall scenario for the reduction of material cost is discussed.