ECN publication
Title:
Industrial cost effective N-PASHA solar cells with >20% efficiency
 
Author(s):
 
Published by: Publication date:
ECN Solar Energy 30-9-2013
 
ECN report number: Document type:
ECN-M--13-026 Conference Paper
 
Number of pages: Full text:
5 Download PDF  

Abstract:
The n-Pasha cell is a bifacial solar cell concept with average efficiencies between 19.8% and 20% and is optimized to enable high efficiencies with narrow distribution on wafers from the complete n-type ingots (2 to 10 ?-cm). This reduces the yield losses from a wafer point of view, which is important since the wafer costs make up the largest part (~40%) of the total module costs for n-Pasha modules. The module fabrication itself adds up to ~35% of the module costs/Wp costs, which leaves ~25% of the costs/Wp for the cell production. We found that the costs/Wp for the 20% n-Pasha cell and module process are very similar to those of a 19% p-type cell, assuming similar wafer and module manufacturing costs. In the paper the successful implementation of a reduction of >60% in BBr3 consumption, and a reduction of >50% in Ag consumption are described, while keeping the n-Pasha cell efficiency at the same level. According to our calculations, the achieved reduction of the Ag and BBr3 consumption will lower the costs/Wp for n-Pasha modules below that of p-type. The majority of the efficiency losses in the n-Pasha cell are due to recombination in the diffused layers and below the contact regions. By tuning both the emitter and BSF profile, an efficiency gain of 0.4% absolute has been obtained. Based on the simulations and experimental results, the path towards further optimization and efficiencies approaching 21% is shown.


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