BIOMIMETIC OPTIMIZATION OF THE GRID DESIGN ON SILICON SOLAR CELLS

摘要

One of the current research challenges in photovoltaics is the optimization of the solar cell grid finger metallization and the enhancement of the efficiency itself. At the moment, standard silicon solar cells use a linear, uniform grid for the power dissipation. Within this work, an alternative, nature inspired metallization structure was developed, utilizing an evolutionary algorithm for the design optimization. Here, the main research goals are the reduction of the shading caused by the front metallization, as well as an enhancement of the power output of the solar cell. For the creation of an alternative metallization structure, possible nature inspired designs are investigated and evaluated, in terms of usefulness for solar cell metallization application. Here, leaf venation systems and river deltas with its branching tributaries served as major inspiration sources. Resulting from these inspirations, a randomly branching structure was developed, utilizing a so called minimal spanning tree for a randomly generated set of nodes. To optimize this nature inspired branching structure, furthermore an evolutionary algorithm was applied for improving the spatial distribution of the pattern. For the validation of the design, electrical solar cell simulations were carried out. In addition, solar cell prototypes were manufactured, utilizing two alternative metallization approaches, inkjet printing and electroplating. Because of minimizing the line width, realized with the help of the alternative metallization approaches, as well as applying the developed bionic design, a reduction of the metal amount of the front metallization and therefore a minimization of the front shading is feasible.