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.