Materials Science and Engineering B 178 (2013) 574–579 Contents lists available at SciVerse ScienceDirect Materials Science and Engineering B j o ur nal homep age: www.elsevier.com/locate/mseb An optimized metal grid design to improve the solar cell performance under solar concentration using multiobjective computation F. Djeffal a,b,∗ , T. Bendib a , D. Arar a , Z. Dibi a a LEA, Department of Electronics, University of Batna, 05000 Batna, Algeria b LEPCM, University of Batna, 05000 Batna, Algeria a r t i c l e i n f o Article history: Received 23 June 2012 Received in revised form 1 November 2012 Accepted 8 November 2012 Available online 20 November 2012 Keywords: Solar cell Multiobjective Optimization Metal grid Efficiency Power losses a b s t r a c t In this paper, a new multiobjective genetic algorithm (MOGA)-based approach is proposed to optimize the metal grid design in order to improve the electrical performance and the conversion efficiency behavior of the solar cells under high intensities of illumination. The proposed approach is applied to investigate the effect of two different metal grid patterns (one with 2 busbars outside the active area (linear grid) and another one with a circular busbar surrounding the active area (circular grid)) on the electrical performance of high efficiency c-Si solar cells under concentrated light (up to 150 suns). The dimensional and electrical parameters of the solar cell have been ascertained, and analytical expressions of the power losses and conversion efficiency, including high illumination effects, have been presented. The presented analytical models are used to formulate different objective functions, which are the prerequisite of the multiobjective optimization. The optimized design can also be incorporated into photovoltaic circuit simulator to study the impact of our approach on the photovoltaic circuit design. © 2012 Elsevier B.V. All rights reserved. 1. Introduction The strong demand for alternatives to fossil fuel based energy sources and growing environmental concerns have increased inter- est in solar cells as a long-term, exhaustless, environmental friendly and reliable energy technology [1–4]. Continuous efforts to develop new materials and modeling techniques for solar cells are being made in order to produce new photovoltaic devices with improved electrical performance. In addition to the new semi conducting materials, solar cells consist of a top metallic grid or other electri- cal contact to collect electrons from the semiconductor and transfer them to the external load. In a solar cell operating under the normal conditions, even a small deviation from the optimum power con- dition can cause a loss of conversion efficiency [1]. Moreover, the enhancement of a solar cell’s conversion efficiency does not only depend on materials and device structure; but it is also very impor- tant to optimize the front metal grid design [1]. Several authors have studied the impact of the metal grid design on the conversion efficiency and the loss mechanism, using different metal grid con- figurations (circular, linear, square, etc.) [1,5–7]. It has been found, in these studies, that the front metal grid design has a great impact on the solar cell electrical performance. The losses associated with the grid influence directly the conversion efficiency of solar cells ∗ Corresponding author. Fax: +213 33805494. E-mail addresses: faycal.djeffal@univ-batna.dz, faycaldzdz@hotmail.com (F. Djeffal). [1,5–7]. This effect is even more pronounced at high intensities of illumination [1,5–7]. Maximum power can be extracted from a solar cell only when it is operating with optimum design parameters. In order to minimize the solar cell power losses and maximize the con- version efficiency, new design approaches are required to enhance the reliability and the electrical performance of the solar cell for photovoltaic applications. Numerous authors have modeled and studied the impact of power loss effect on the solar cell electrical behavior, where analytical and empirical methods have been used to minimize the loss effect. In these techniques, the global optimiza- tion of the power loss effect cannot be achieved [1,5–8]. In addition, until now, there are no studies to investigate the global electri- cal performance optimization of the metal grid design by using a global evolutionary-based optimization technique. One preferable approach is the multiobjective-based optimization, which could provide practical solutions for the photovoltaic circuit design. The first step of our approach consists of an accurate analytical pre- sentation of different loss mechanisms including solar illumination effect. The different analytical models will be used in our study as objective functions. In this paper, we present the applicability of the multiobjective genetic algorithm (MOGA) computation approach to optimize the front metal grid design for photovoltaic applications. The key idea of this approach is to find out the best dimensions and electrical parameters of the metal grid to facilitate and improve the device design strategy. The MOGA-based approach, adopted in this work, is the process of finding the minimum/maximum of the power losses and conversion efficiency. These latter called the objective 0921-5107/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.mseb.2012.11.006