Sustainable Solar Module Through the Substitution of Materials by Renewable Encapsulation, Recycled Backsheet, and Lead-Free Interconnection

Sustainability and resource-efficiency are the major topics for the 21st century. Most of the PV modules are manufactured of glass, polymers, metals, and silicon-based solar cells. All these materials have the potential to be substituted by sustainable products. The substitution of materials for PV modules is challenging because of issues in significant unknown risks for short- and long-term reliability of the PV module. Investigations for material and process routes of a 100% renewable solar module are necessary. This study investigates the suitability and reliability of different materials. For example, the reliability of an electrically conductive adhesive (ECA) to a leaded-solder reference is under investigation as well as various polymers (recycled, bio-based, or biodegradable). In the first step, the interconnections are tested with a standard module encapsulation bill of materials (known good reference). In the second step, the module encapsulation and backsheet materials are substituted by their sustainable counterparts. The goal is to identify the most promising material combinations for further integration of lead-free interconnected solar cells. Reliability is assessed using accelerated ageing tests in accordance with IEC 61215/IEC 61730 with standard test duration and extended test duration for each material and interconnection batches. The condition of the samples is assessed by regular visual inspection, power measurements, and electroluminescence images. The study aims to demonstrate and assess the suitability and reliability of the selected material combinations to enable the steps toward a renewable material solar module.