Optimized production of photovoltaic cells via laser technology

Laser technology can contribute to increasing the efficiency of production of photovoltaic cells and thereby to reducing the price of power harvested from sunlight. The EU project SOLASYS, led by the Fraunhofer Institute for Laser Technology (ILT) in Germany, has shown how this is possible. Both established and novel concepts for solar cells will profit from this research. “The primary goal of this demonstration project is to increase throughput and thus the efficiency of solar cells,” explains the author of the study, Alexander Olowinsky.

Cheaper production and increased efficiency

The high costs of materials and production of solar cells are the primary reasons for the high price of photovoltaic power. Raising the present maximum 16% efficiency of solar cells could reduce the price of generated power. Here laser technology offers numerous advantages in material processing due to its non-contact processing, its controlled energy release, and its high speed and precision. “To date laser technology is used in photovoltaic cell production only for edge insulation and drilling,” according to Olowinsky. However, a multitude of applications is possible. “Initial studies have already demonstrated basic options for applications. Now it is a matter of demonstrating feasibility.”

Laser drilling, which occurs with up to 100 hair-thin drillings per second, enables leading metal contacts from the front to the back of the cell. Thereby both electrical poles are on the back, which prevents shadows and increases the efficiency of the cell. Likewise soldering of two cells to a module can be optimized with laser technology. Because soldering temperature can be controlled exactly and modulated using a laser, the laser power is simply adjusted on temperature deviations at the solar cell. This increases the quality of soldering points and reduces the heat load. Similar improvements are expected from using lasers for removing thin coatings without damaging the substrate, in insulating the front and back, and in selective doping.

In a few years, the price of solar power will match conventional power
Prognoses of the European Photovoltaic Industry Association assume that the installed capacity of photovoltaic systems will grow by a factor of ten in the next eight years, although solar current will not match the price of conventional power until 2015. Olowinsky also considers these estimates realistic. “However, that does not depend alone on the production of cells, but also on the development of module production and the overall handling,” the researcher advises.

Source: Pressetext.at