Enhancing the Power Output of Bifacial Solar Modules by Applying Effectively Transparent Contacts (ETCs) With Light Trapping

We have performed a computational study on the enhancement of the power output of bifacial solar modules with effectively transparent contacts (ETCs). ETCs are triangular cross-sectional silver grid fingers that redirect light to the active area of the solar cell, therefore mitigating grid finger shading losses. Furthermore, ETCs can be spaced densely leading to light trapping. We modeled bifacial silicon heterojunction solar modules with varying front and rear illumination and ETC coverages. We determined that shading losses can be almost fully mitigated and that light absorption can be increased by up to 4.7% compared with state-of-the-art screen-printed bifacial modules. Furthermore, we calculated that grid resistance and silver usage can be improved when using ETCs. ; © 2018 IEEE under the IEEE Open Access Publishing Agreement. Manuscript received April 5, 2018; revised May 31, 2018; accepted June 3, 2018. This work was supported in part by the Engineering Research Center Program of the National Science Foundation (NSF) and the Office of Energy Efficiency and Renewable Energy of the Department of Energy under NSF Cooperative Agreement EEC-1041895 and in part by the U.S. Department of Energy through the Bay Area Photovoltaic Consortium under Award DE-EE0004946. The work of R. Saive was supported by the Global Climate & Energy project. The authors would like to thank J. Lloyd for helpful advice on LightTools optical simulations and P. Jahelka for helpful discussion. ; Published - 08396847.pdf