Laser Material Processing in Crystalline Silicon Photovoltaics Alphonse Niyibizi, Bernard W. Ikua, Paul N. Kioni and P.K. Kihato Abstract --Lasers play a major part in the processing of the numerous materials used in engineering and manufacturing. The range of processes in which lasers are involved is ever increasing. One of the areas in which laser has recently found application is in energy systems. With the dwindling non-renewable sources of energy such as fossil fuels and increasing demand of electricity, there is increasing interest in addressing the energy problem through development of systems for renewable energy alternatives such as solar energy. Though solar energy is readily available and has no adverse effects on environment such as pollution and greenhouse effects, it has not been fully exploited due to a number of challenges. Some of these challenges include high capital cost and the low conversion efficiency. Therefore photovoltaic industry has taken advantage of the benefits inherent in laser technology, namely accuracy, cost-efficiency, and flexibility that are critical in manufacturing today. This paper presents a review of the various production and assembly methods employed in the manufacture of solar panels where laser technology plays a predominant and the types of lasers are preferred along the photovoltaic production chain from the silicon raw material to the finished laminated solar modules. Keywords-- In-laminate laser soldering, Laser, Metal-to-plastic joining, Monocrystalline solar cell, Photovoltaic, Solar panel assembly. I. INTRODUCTION: LASER MATERIAL PROCESSING VER the last two decades laser processing has become an indispensable part of competitive manufacturing throughout the world. Whether the project involves metal, glass, plastic, silicon, rubber, or even wood, laser materials processing has proven its superiority in terms of accuracy and process efficiency. laser materials processing refers to a number of different types of processes all utilizing the unique benefits offered by laser light. These processes include welding, cutting, cladding, heat treating, machining and drilling which are easily accomplished with lasers instead of traditional manufacturing techniques, tools and machinery. Laser processing has a number of important benefits over other available methods. One of the benefits of laser processing is its ability to work with many different types and shapes of materials. Traditional drilling methods, for example, are difficult to use on rounded materials. With laser drilling, a non contact process, geometric limitations are easily overcome with conventional or shaped holes easily processed. Additionally, cutting certain materials has always been nearly impossible for standard machinery, but with lasers, it is easy to burn, vaporize, or melt away the edges to leave a clean consistent cut. Another benefit is efficiency; for example, the use of laser in processing is faster than traditional industrial methods in say, welding, cutting, and drilling. As a result higher production rates are achievable with laser. Moreover, since laser processing does not require direct contact between the materials and the equipment, there is no wear nor tear on the tools and there is little down-time. Of course, one of the most important benefits of laser processing is precision. Due to the fact that the positioning of laser beam is computer controlled and that there is no direct contact of the workpiece with the laser equipment much higher accuracy is achieved than for any of the conventional equipment. In conventional processes, as tools become worn they also become less precise. That never happens with laser processing the first cut is as precise as the thousandth cut. The bottom line is that accuracy, cost-efficiency, and flexibility are critical in manufacturing today when saving money and preserving quality are the keys to staying ahead of the game. Laser processing can be the solution that provides all three of those factors [1, 2]. Laser technology can be used in processing of almost all types of materials including the hardest and most difficult to materials. Some of the meaterials that are easily cut with lasers include super alloys such as Inconel, Waspaloy, titanium and many aluminum alloys. II. LASER TECHNOLOGY IN PHOTOVOLTAICS When it comes to laser technology, photovoltaic industry has not been left behind and most of the numerous processes in cell manufacturing and modules assembly use in one way or another laser technology. The involvement of laser systems depends on the type of the initial material, crystalline or polycrystalline silicon or thin film solar cells, et cetera. Alphonse Niyizibi, School of Engineering, Department of Mathematics and Physical Sciences, Kimathi University College of Technology (corresponding author, phone: +2540724970311; e-mail: nieysal@gmail.com). B.W. Ikua, Department of Mechatronic Engineering, JKUAT (e- mail: ikua_bw@eng.jkuat.ac.ke). P.N. Kioni, Kimathi University College of Technology (e-mail: (ndirangukioni@yahoo.com). P. K. Kihato, Department of Electrical and Electronic Engineering, JKUAT (e-mail: kamitakhat1@gmail.com) ISSN 2079-6226: Proceedings of the 2012 Mechanical Engineering Conference on Sustainable Research and Innovation, Volume 4, 3rd-4th May 2012 69