The Recycle Process for Crystalline Silicon Solar Module

• DOI: 10.4229/27theupvsec2012-6cv.4.3
• Publication Date: 2012-10-26
• Authors: S.-W. Chen; C.-H. Du; J.-C. Hsiao; T.-Y. Wang
• Keywords: Sustainability Aspects; PV - a Major Electricity Source; 7. Clean energy; 12. Responsible consumption

27th European Photovoltaic Solar Energy Conference and Exhibition; 4642-4644<br/>Although the solar energy is a green energy without pollution, the waste of solar module is still a problem. Herein we propose a recycle process to recover the materials from crystalline silicon module. A thermal annealing step with well controlled temperature can separate the glass from module without breaking. The EVA and Tedlar were separated and burned out at different temperature. The recycled glass was clean, completely, and could be reused again for solar module encapsulation. The recovered solar cell chips, which were breaking during high temperature annealing, were etching with hydrochloric acid solution to remove the aluminum back side contact. And then be etching with hydrofluoric acid solution to remove the silver front contact and SiNx anti-refraction coating layer. The emitter layer and the back side field layer (Al-BSF) were removed by following alkali solution etching. Finally a pure silicon material was obtained. The recycle yield of silicon was 62% (base on the textured silicon weight inside the module) and the purity was ~8N. The copper could be recovered by removing the out skin of tinlead alloy in further acid etching step. The recycle yield of copper was 85%.<br/>