Peter John Cousins

Generation 3: Improved performance at lower cost

This paper reports recent progress by SunPower Corporation to commercialize the Generation 3 product. The Generation 3 product has been designed to deliver both increased performance and lower manufacturing cost. Improved performance was achieved through optimization of the diffusion recombination losses. A conversion efficiency of 24.2% was achieved on a champion cell made on production equipment using a production wafer, 155.1cm2 n-type CZ. This result was verified by the National Renewable Energy testing Laboratory. Modules made with Generation 3 cells were measured by NREL to have > 20.4% total area efficiency (>332W with 1.63m2 modules). This paper presents the design changes before detailing the resulting performance.

Toward the Practical Limits of Silicon Solar Cells

This paper reports recent efficiency results achieved by SunPower (SPWR) using industrially relevant manufacturing processes and then reexamines the following age-old question: “What efficiency can a single-junction Silicon solar cell suited to large-scale manufacturing achieve?” Through examination of a gap analysis of the SPWR cell and use of other relevant proof-points, insights are provided into the remaining challenges to achieving the practical limits.

Generation III high efficiency lower cost technology: Transition to full scale manufacturing

This paper reports on the first large scale manufacturing of Gen III solar cells. The Gen III product has been designed to deliver increased performance and lower cost throughout the value chain. Reduced emitter recombination is the key feature to deliver the efficiency improvement. Gen III is now ramping on a production line in SunPowers Philippines manufacturing plant. Production run median efficiency is 23.6%. Total area module efficiency is 21.2 %. The Gen III solar cell architecture has a low breakdown voltage in reverse, which minimizes power loss and wear on module materials under shaded conditions.

SunPower's Maxeon Gen III solar cell: High efficiency and energy yield

SunPower is currently shipping the highest efficiency commercial solar panel in the 20% efficiency E-series with high reliability, and proven high energy yield per rated watt [1,2]. This paper discusses the next generation SunPower solar cell, the Maxeon Gen III used in the recently launched X-series modules. Higher efficiency, improved field performance from lower temperature coefficient, improved reliability due to low reverse breakdown voltage and a uniform dark appearance are the characteristics of this technology. The SunPower Maxeon Gen III solar cell is a high efficiency design intended to reduce cost throughout the value chain by improved performance. The improved efficiency is due to a passivated contact structure lowering the cell emitter recombination to approximately 15 fA/cm2 [3]. The process is currently in full scale manufacturing at approximately 100 MW per year in the SunPowers Fab2 production facility in the Philippines.

Simulation and characterization of high efficiency back contact cells for low-concentration photovoltaics

Herein, the performance of low-cost crystalline silicon solar cells under low to medium levels of concentration is explored. Simulations and experimental results are shown for concentrations up to 20 suns. An efficiency of 23% at 9 suns is achieved on a 34.5 mm x 125 mm solar cell using SunPowers standard production process. Low sensitivity of cell performance to illumination profile and position is also demonstrated.

Grid-Competitive Residential and Commercial Fully Automated PV Systems Technology: Final technical Report, August 2011

SunPower Corporation is performing work under the U.S. Department of Energys Solar America Initiative. We have assembled a diverse team of leading companies, including several small businesses, to form our Technology Pathway Partnership (TPP) and believe that, through our combined efforts, the programs Levelized Cost of Energy (LCOE) goals for 2010 and 2015 can be met. This is a Systems Class TPP program in which our team addresses technology from silicon crystal growth to systems installed in the field. The Technology Pathway Partners include SunPower, as the prime recipient, and Solaicx, SiGen, Dow Corning, STR, Xantrex, and NREL, as sub-recipient partners.