PARIS – Nanoelectronics research center IMEC (Leuven, Belgium) and photovoltaics manufacturer SolarWorld AG said they have demonstrated ultra-thin (100 µm), large-area (156x156mm˛) PERC-type (passivated emitter, rear cell) mono-silicon solar cells integrated in a 255Wp class A module.
IMEC and SolarWorld said they co-developed PERC-based modules had been manufactured on SolarWorld's fully automated production line without significant wafer breakage.
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The research partners said modules contain 60 randomly selected i-PERC cells, co-fabricated by Imec’s PV research group and SolarWorld Innovations (SWIN), starting from 120-µm thin Cz-silicon wafer material. After surface decoupling and junction formation at SWIN, IMEC said it performed rear-side passivation and rear laser ablation. The rear aluminum metalization was deposited at SWIN, while IMECconducted the silver screen-printing, co-firing and characterization.
They also claimed they have measured an averaged cell efficiency of 18.5 percent (+/- 0.5 percent), with a best cell performing at 19 percent efficiency. Eventually, enough cells for module production with 18.5 percent (+/-0.2 percent) were implemented in 60cell class A standard modules using SolarWorld’s module manufacturing line.
The modules demonstrated a power higher than 255 Wp measured at SolarWorld’s Module Testing Lab.
"The low breakage rate in the i-PERC production and in the fully automated module fabrication, together with the narrow processing distribution of the cell results demonstrate that a serious reduction of silicon material is feasible in highly efficient PERC solar cell production,” said Joachim John, IMEC's R&D PV project manager.
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With solar panel prices plunging, it's unclear whether incremental steps like this will help. Several startups have been trying other approaches like reducing the cost of materials such as polysilicon or squeezing as much efficiency as possible from the installed based through approaches like using robots to align solar arrays to track the sun (the approach eliminates costly motors).
Then there's the difficulty of competing with relatively cheap and plentiful energy sources like natural gas. Still, any improvements in solar efficiency help.
Imec and SolarWorld specified that this collaborative work had been achieved as part of the EU-funded ultra-thin solar cells for module assembly -tough and efficient (ULTIMATE) project.
See here: http://cordis.europa.eu/search/index.cfm?fuseaction=proj.document&PJ_RCN=10502366