Lead-Free PV Modules: Industrial Realization and Evaluation of Environmental Impact

With the large amount of photovoltaic (PV) modules required for a more renewable energy sector, strategies to avoid the toxic material lead, which is still present in most conventional modules today, becomes more and more relevant. This work presents the result of the government-funded research project “BermUDa”, in which the industrial realization and environmental impact of lead-free modules was investigated. The herein chosen approach was to directly replace lead-containing module materials (namely metallization paste and solder cell connectors) with lead-free alternatives, while leaving the industrial production process as unchanged as possible. For this, a large number of preprocessed silicon wafers underwent cell (PERC) and module production, where the processability was tested and compared with conventional lead-containing materials. Subsequently, the performance of the products (cells and PV modules) was tested and compared in terms of electrical performance and reliability in power measurements and accelerated aging tests, respectively. The project thereby demonstrated the feasibility to work with lead-free technologies and adapt currently established industrial processes to produce completely lead-free PV modules that can compete with their lead-containing counterparts in terms of sustainability and costs (LCOE). The work also suggests focus on cell metallization pastes, driven by future market demand, to develop lead-free pastes that can achieve better fine line printing capabilities to allow greater flexibility when converting an existing production line to produce lead-free PV modules.