Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Avoiding efficiency losses in silicon solar cells already in the production process

28.10.2015

From basic idea to implementation: University of Konstanz, Germany, invested 10 years of research and development work: Under operating conditions, however, Cz-silicon solar cells suffer from so-called light-induced degradation (LID), due to which the efficiency of a Cz-silicon solar cell is considerably reduced after only a few hours of exposure to solar radiation. Depending on the material and production process, the loss in efficiency can be more than one percent absolute.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Konstanz in patenting and marketing its innovation.

One of the biggest challenges in the context of ‘renewable energies` is the even more efficient use of the raw materials available to us. Particularly when it comes to generating electricity from sunlight, a lot of research is carried out on how to further increase conversion efficiency of solar cells.


Researchers at the Photovoltaics Division of the University of Konstanz: Professor Giso Hahn, Svenja Wilking und Axel Herguth (from left).

TLB GmbH

In the past decade, the efficiency of solar cells in industrial mass production has been continuously improved. About 15 years ago, solar cells were able to convert only approx. 15 percent of solar radiation into electricity. In the meantime, efficiency could be increased to approx. 20 percent.

This excellent efficiency is only reached on industrial scale with monocrystalline solar cells using silicon wafers grown by the Czochralski (Cz) technique. Under operating conditions, however, Cz-silicon solar cells suffer from so-called light-induced degradation (LID), due to which the efficiency of a Cz-silicon solar cell is considerably reduced after only a few hours of exposure to solar radiation. Depending on the material and production process, the loss in efficiency can be more than one percent absolute.

Researchers at the Photovoltaics Division of the University of Konstanz introduced a method to neutralize this type of degradation as early as in 2006. The process developed and optimized over the years by Axel Herguth, Svenja Wilking and Professor Giso Hahn can easily be integrated into the production process. The scientists made use of the fact that the degraded solar cells can be regenerated by exposing them to light energy at temperatures above 100 degrees Celsius. Alternatively, regeneration can also be achieved using voltage instead of light.

The regeneration process can be integrated at different stages into the production sequence, for solar cells, e.g., directly after the co-firing process or separately at the end of production. Another option is to apply the regeneration process to finished modules.

The economic potential of the regeneration effect is enormous: If the degradation-caused loss in efficiency of one percent absolute is nearly completely offset, this results in an additional power output of approx. five percent. With a 100 MWp line, this corresponds to more than one million euros per year.

"This means the return on invest is secured after only a few months, which significantly increases economic attractiveness and the opportunities for use of this groundbreaking technology," explains Professor Hahn, Head of Photovoltaic Division at the University of Konstanz.

Patents for the process and the regeneration furnace have already been granted in the most important industrial nations and regions such as in the United States, in Europe and China. In the meantime, first installations based on the patented method have been integrated into production processes. However, it is also likely that a number of imitation products have appeared on the market. "Our key challenge for the coming years will be to enforce the patents held by the University of Konstanz," says Dr.-Ing. Hubert Siller, Innovation Manager at TLB, Karlsruhe.

In recent years, this well-known method has been further developed and modified by Axel Herguth and Svenja Wilking, who are engaged in research at the University of Konstanz. The enhanced process control allows the regeneration process to be carried out much faster during the co-firing step. According to the researchers, this is due to a larger amount of hydrogen released from the silicon nitride anti-reflective coating into the silicon during co-firing. The process can thus be sped up considerably, improving its efficiency and making it attractive for inline processes in industrial mass production, for example. Ideally, this process may follow or even be integrated into the co-firing step. Professor Hahn is optimistic about the future: "We are confident that the regeneration method discovered and developed by our team of researchers will become an integral part of a lot of new solar cell production lines because it helps to achieve the high level of stable efficiency that is required by the market. Moreover, current production lines can be retrofitted with minimal effort by using this unique regeneration technology.”

Technologie-Lizenz-Büro (TLB) GmbH supports the University of Konstanz in patenting and marketing its innovation. Acting on behalf of the University, TLB is in charge of the commercial implementation of this future-orientated technology at a global level. For more detailed information, please contact Dr.-Ing. Hubert Siller, email: siller@tlb.de

Weitere Informationen:

http://www.tlb.en
http://cms.uni-konstanz.de/en/physik/hahn/

Annette Siller | idw - Informationsdienst Wissenschaft

More articles from Power and Electrical Engineering:

nachricht Producing electricity during flight
20.09.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Solar-to-fuel system recycles CO2 to make ethanol and ethylene
19.09.2017 | DOE/Lawrence Berkeley National Laboratory

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>