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The paper addresses the need to simplify the comparison between different climatic conditions. Therefore, the concept of Mission Profiles is introduced to PV. Mission Profiles are a set of climatic stresses compiled to allow direct comparisons such as temperature, humidity, and UV exposure. The use-case in this paper is a comparison of a temperate with a hot climate. The results show that temperature driven processes are highly accelerated for the hot climate, whereas processes that involve humidity may lead to a similar annual degradation. The impact of light, particularly UV, is even more complex. UV triggered reaction processes can be photon absorption triggered and accelerated by temperature. However, for most observed interactions and material changes UV light goes in conjunction with moisture (H2O) for the chemical reaction and is accelerated by temperature. Calculating the impact of temperature and UV is possible. However, the impact of moisture is almost impossible as it requires the knowledge of the local microclimate. Only a “worst-case” scenario can be assumed while using ambient relative humidity for most events of the day, that, however, do typically not include condensation. With the introduction of Mission Profiles, it should be possible to assess stress more easily for particular sites in general. Differences in mounting such as open rack compared to e.g., BiPV can also better addressed, however, with some assumption to define the microclimate (e.g., exclude rear side cooling).

It was previously shown that the Laser Enhanced Contact Optimization (LECO) Process is a promising boost for PERC and TOPCon cell manufacturing enhancement. In this contribution, a method is developed to assess the long-term stability of industrial LECO treated PERC cells in a module compound. Therefore, extended accelerated aging tests as well as outdoor measurements were performed on modules comprising LECO treated cells as well as untreated references. It is described, how data can be evaluated to separate typical, known aging and degradation effects from presumable LECO specific effects. The results of this work show that test modules comprising LECO treated cells did not show a different behavior in the accelerated aging or degradation compared to the reference. The same conclusion was found for thermal cycling and damp heat tests, both far in excess of IEC requirements, as well as in a sequential test sequence. In addition, their outdoor performance with local and integral measurements has been evaluated. We can conclude that for the tested PERC cells, aging and degradation effects appeared, but none of them could be attributed to the LECO process. Hence, improvements in the efficiency and/or yield on cell level due to LECO can be translated to the module or even system level considering typical aging and degradation behavior, independently of a prior LECO process.

According to the International Technology Roadmap for Photovoltaics, passivated emitter and rear solar cells dominate the market in 2021 of up to 80% and are forecast to remain state of the art at least for the next 5 years. Within the production process of solar cells, it is typical to have cells with lower efficiency grades due to variations in manufacturing processes or material defects. Reprocessing such solar cells could save cost due to increased production yield and simultaneously reduced cost for recycling of unusable/unsellable low‐efficiency cells. Herein, the impact of the laser‐enhanced contact optimization (LECO) process on the power output and reliability of solar modules using commercial off‐spec cells of different manufacturers is analyzed. LECO is a downstream process for optimizing metal−semiconductor contacts on finished solar cells. The treatment leads to a significant economic gain due to enhanced cell efficiency (Wp ↑, therefore manufacturing cost per Wp ↓) even of already good solar cells. Herein, the first evaluation of the impact of the LECO process on the cell output power on an industrial scale (>1000 cells) and on module reliability is presented. The results for common short‐term effects like light‐induced degradation and light‐ and elevated temperature‐induced degradation are within expected limits and the durability against, for example, potential‐induced degradation is not changed due to the LECO process. The results further show that cell sorting is crucial for a reliable module and to avoid outliers in terms of unexpected degradation and recovery phenomena of individual cells. [ABSTRACT FROM AUTHOR]