Mosaic Module Concept for Cost-Efficient and Aesthetic BIPV Modules

We present a module concept based on metal-wrap-through solar cells and conductive copper backsheets that offers a high degree of aesthetic freedom and allows individual designs. Our metal-wrap-through cell design features sub-cells that allow splitting and individual cell sizes enabling a flexible module design. We show results from sample manufacturing and façade mock-up implementation. The manufacturing is performed using automated equipment and low-temperature solder pastes. The process step of “tabbing/stringing” can be omitted compared to conventional PV module manufacturing. We perform IV measurements and a cell-to-module loss analysis. Results show that, considering the aperture area of the cells, competitive cell-to-module power ratios (~95%) are achieved. We estimate the mosaic module costs to be between 57 and 68 €/m² (depending on specific design) compared to 45 €/m² for common industrial, utility scale solar modules

Modelling of silicon solar cells by using an extended two-diode-model approach

The present work is related to effects originating from the spatial character and therefore referring to the distributed resistance of a silicon solar cell. Two effects are regarded: Firstly, the bending of the illuminated IVcurve particular at open-circuit-conditions towards a lower voltage due to an increased metal/emitter resistance. Secondly, enhanced fill factor losses due to lateral current paths in case of back contact solar cells. A simple approach is presented by taking into account a second one-diode-model in addition to a conventional standalone one-diodemodel. The key idea is simple: By separating these models by a resistor, diodes are forward biased differently as it is the case in real operation conditions and internal current flow leads to a distortion of the measurable global IV-curve. We show that results achieved by the so called "distributed-two-diode-model" give already comparable results to far more complex two-dimensional finite element simulations utilizing Sentaurus TCAD