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 58 and 70 €/m2 (depending on specific design) compared to 45 €/m2 for common industrial, utility scale solar modules.

The interconnection of solar cells by shingling increases the active cell area in photovoltaic modules. Cell-to-module (CTM) gains and losses change significantly. We present models to calculate these gains and losses for shingled cells. Module efficiency and power can be increased with the shingle interconnection technology by +33 Wp and +1.86% abs in the analyzed design, when compared to common ribbon-based interconnection. The CTM-ratio for efficiency improves due to shingling and also the CTM-ratio for power increases compared to conventional modules with ribbon or wire cell interconnection.

Printed module front covers can be designed to mask the geometry of solar cells for BuildingIntegrated Photovoltaics (BiPV). Such prints reduce the transmittance of the module front layer, which decreases module power. We performed transmittance measurements with large-area and small-area measurement equipment (220 mm / 620 mm integrating sphere) on different samples and find measurements applying small-area illumination to result in lower transmittance (Δ = 3.1abs% at 40% coverage) due to lateral losses in the samples. By measuring the power of modules with different design prints we find that the results do not correspond to transmittance measurements of the glass covers alone, even if a large-area transmittance measurement setup is used (Δ = 16%abs at 40% coverage). We attribute the differences between optical and electrical measurements to module internal reflection, optical coupling of the solar cell, partial transmittance by coatings and diffuse scattering of decorative prints. Differences increase with the share of coated glass area. We perform electrical and LBIC measurements on modules with printed and unprinted reference glass covers and calculate the effective transmittance. Short circuit currents calculated by spatial integration of LBIC results are in good agreement with results from ISC measurements. We predict the effective transmittance for arbitrary prints based on selected ISC measurements and find them to be in good agreement to measurements. In conclusion, we find transmittance measurements on printed glass alone to be insufficient to predict the optical power losses as they overestimate the optical loss.

Different approaches like round wire interconnectors, shingled or back-contact cells have been presented in the past to improve the cell-to-module efficiency ratio by reducing the shading losses of interconnector ribbons. We present a new cell interconnector design based on a triangular cross section to further improve modules based on interconnector ribbons. We analyze the optical behavior of the concept and compare it with rectangular ribbons and round wire interconnectors. An evaluation of the new concept using optical ray tracing is performed. Results show an advantage in optical performance of 2.35% of the new concept compared to standard interconnector ribbons under perpendicular irradiation as well as 1.94% compared to round wires. An analysis using irradiation data (DNI) shows a superior optical performance of the TriCon-Concept. We find that in an elevation tracked module using TriCon 2.32% more light reaches the cell surface over the year compared to rectangular interconnectors (5BB) and 2.02% compared to round wires.

The mounting system of photovoltaic (PV) modules has a significant impact on the thermo-mechanical stress in PV modules. In this work the clamping of framed PV modules is compared to the clamping of unframed PV laminates by a simulation study using the finite element method (FEM). The FEM modelling allows to calculate the local stress distribution in the solar cells directly. We present results from a model of a standard glass-backsheet PV module with 3 mm glass under homogenous mechanical pressure load of up to 5400 Pa. The thermal stress from the lamination process is considered as a pre-study, similar to [1]. The frameless clamped PV laminate shows a significantly larger displacement of 147 mm than the framed PV module with 54 mm for 2400 Pa. In line with the findings of Kajari-Schroeder [2] we simulate an elliptic deflection distribution for the framed PV module, whereas the clamped PV laminate shows a wave-like shape. Consequently, the area of high tensile stresses in the silicon solar cells, with a maximum value of 142 MPa at 2400 Pa load, is narrowly located around the highest curvature at the center of the framed PV module. In case of the frameless clamped PV laminate we identify four areas of high tensile stresses with a higher maximum value of 218 MPa. The results show that the frame reduces the tensile stresses in the solar cells significantly compared to unframed laminates.

A multi-use and low cost silicon concentrator solar cell and receiver concept is presented. It is based on a industrially feasible Metall Wrap Through concentrator solar cell available in various dimensions up to 156x156m. Solar cell performance evolution and current results are reported, with a top efficiency of 20.2% at 1W/cm(2) irradiance. The interconnection and receiver integration of the cells is demonstrated with several prototypes. A maximum cell-to-receiver efficiency of 99.3 % is shown, and a top receiver efficiency of 19.2 % at 1W/cm(2) irradiance is measured. Preliminary reliability testing sequences (humidity freeze, thermal cycling) and outdoor exposure results are passed without significant damages or IV power degradation (<1%).

The authors combine a silicon-based metal-wrap-through architecture with a unit cell designed for the purpose of operating under concentrated irradiance, called AP-MWT solar cell. On the illuminated side, the negative polarity is electrically separated by using an emitter window surrounding the perimeter of each unit cell. The final solar cell device consists of an arbitrary number of unit cells with sizes ranging from 1 × 2.25 cm 2 up to 14 × 13.5 cm 2 . The Czochralski based bulk material as well as the manufacturing approach use state-of-the-art industrially feasible technologies alone. Results show a plateau between concentration factors from 5 to 12 reaching efficiencies above 20.0%. An average efficiency of 19.8±0.15%, for over 150 AP-MWT solar cells measured at a concentration factor of 10, is reported. Details on the interconnection and module design will be discussed in another contribution to this conference.

A versatile interconnection and receiver concept for back contact low concentrating crystalline solar cells is presented. The key feature is the AP-C-MWT cell which allows for any cell formats as a multiple of 22.5 × 10 mm2. We demon-strate the feasibility of an adequate receiver concept and show the electrical optimization steps for a given concentration. The steps include the electrical finite-element-method (FEM) simula-tion of the interconnector conductivity and an analytical model to derive the optimal geometric design. Finally measured efficiency data for a built prototype are reported, showing a receiver effi-ciency based on string area of 19.2% (C=9.9) and a cell to receiv-er efficiency of 99.3%.

A hybrid concentrator PV-Thermal (CPV-T) system for delivery of electricity and 150 C hot fluid in a structure suitable for roof-top installation on domestic, commercial, and industrial buildings is being developed by ANU in collaboration with the University of New South Wales, CSIRO, and industry partners. A first design based on beam-splitting utilising liquid-absorption filters is being analysed, with a study of the most suitable candidate fluids. An initial selection of four liquids was conducted; with the liquids subjected to accelerated tests to analyse their long-term performance and possible optical and chemical degradation. Some of the fluids showed optical changes after high temperature test and UV exposure, leading to slight yellowing.

A first prototype of the hybrid CPV-T ANU-Chromasun micro-concentrator (MCT) has been installed at The Australian National University (ANU), Canberra, Australia. The results of electrical and thermal performance of the MCT system, including instantaneous and full-day monitoring, show that the combined efficiency of the system can exceed 70%. Over the span of a day, the average electrical efficiency was 8% and the average thermal efficiency was 60%.