Product Code: ICAL07_306

Laser Technology for Solar Cells and Solar Receivers
Authors:
Aart Schoonderbeek, Laser Zentrum Hannover e.V.; Hannover Germany
Lars Richter, Laser Zentrum Hannover e.V.; Hannover Germany
Rainer Kling, Laser Zentrum Hannover e.V.; Hannover Germany
Andreas Ostendorf, Laser Zentrum Hannover e.V.; Hannover Germany
Berend Denkena, Laser Zentrum Hannover e.V.; Hannover Germany
Rainer Grischke, ISFH; Emmerthal Germany
S. Mau, ISFH; Emmerthal Germany
N.P. Harder, ISFH; Emmerthal Germany
R. Brendel, ISFH; Emmerthal Germany
Presented at ICALEO 2007

During the last years, solar energy conversion by photovoltaic and solar receivers has grown enormously. For the future efficient and durable products at low cost are necessary Laser technology offers many opportunities to realize this. Two technologies are discussed in this paper.
First, a technology is discussed for producing solar receivers. A requirement of a solar receiver is a vacuum sealing between the absorber and the cover glass tube for at least 25 years. To realize this glass and metal are directly fused. To obtain a stable process and to avoid chemical interaction between a gas flame and the fusing zone a CO2-laser is used in combination with a process temperature controller. This paper shows results of the developed laser process compared with a flame fusing process.
The second technology discussed is used for producing silicon wafer based solar cells. A method to reduce costs is reducing the thickness of the wafers. Consequently, contact and pressure-free laser processing has large advantages. Experimental investigations are discussed for producing grooves and holes for new solar cell concepts. Damaging of silicon around the processing area should be avoided. Results obtained with different laser types are compared regarding the quality, speed and costs.