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Photovoltaic cells are produced as thin flat layers. They behave as a brittle and elastic material that fails at a given level of stress. Conforming cells into curved geometries will a priori induce both flexure and membrane stres...
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Photovoltaic cells are produced as thin flat layers. They behave as a brittle and elastic material that fails at a given level of stress. Conforming cells into curved geometries will a priori induce both flexure and membrane stresses. In the present work, an analytical model is derived to predict both stress distributions and intensities in a mono‐crystalline pseudo‐square cell. Furthermore, a second model is derived to find the main stresses within fractions of cells. For conventional cell dimensions, solutions predict a transition from flexure to membrane dominated stresses for most conformations as curvature increases. As a consequence, near failure stresses are mainly determined by cells size and aspect ratio. In contrast, flexion is the main contribution in a small subset of the curvature space or for small curvatures. In the corresponding cases, stresses scale in proportion to cells thickness. As a consequence, cell size and/or shape is the main parameter to reduce internal stresses in most cases. In particular, the use of fractions of cells can substantially decrease membrane stresses and thus increase the maximum curvature. For instance, in a case study with M0 cells and curvature radii of a few meters, the highest predicted tensile stress is 45 MPa. In such a case, the larger M12 format gives a prediction of 65MPa. In contrast, thirds of cells give predictions of 25 and 30MPa, respectively.
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Building-integrated photovoltaics (BIPVs) and vehicle-integrated photovoltaics (VIPVs) receive solar irradiance through non-uniform shading objects. Standard scalar calculations cannot accurately determine the solar irradiance of ...
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Building-integrated photovoltaics (BIPVs) and vehicle-integrated photovoltaics (VIPVs) receive solar irradiance through non-uniform shading objects. Standard scalar calculations cannot accurately determine the solar irradiance of BIPV and VIPV systems. This study proposes a matrix model using an aperture matrix to accurately calculate the horizontal and vertical planes affected by non-uniform shading objects. This can be extended to the solar irradiance on a VIPV by applying a local coordinate system. The 3D model is validated by a simultaneous measurement of five orientations (roof and four sides, front, left, tail, and right) of solar irradiance on a car body. An accumulated logistic function can approximate the shading probability. Furthermore, the combined use of the 3D solar irradiance model is effective in assessing the energy performance of solar electric vehicles in various zones, including buildings, residential areas, and open spaces. Unlike standard solar energy systems, the energy yield of a VIPV is affected by the shading environment. This, in turn, is affected mainly by the location of vehicle travel or parking in the city rather than by the climate zones of the city.
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Solar-powered vehicles have the potential to reduce CO2 emissions, operational costs and charging frequency needs of electric vehicles. This potential will depend on the local solar irradiation but also shadowing conditions, a rel...
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Solar-powered vehicles have the potential to reduce CO2 emissions, operational costs and charging frequency needs of electric vehicles. This potential will depend on the local solar irradiation but also shadowing conditions, a relevant issue for urban contexts. The potential of solar-powered vehicles in the urban context is modelled for 100 cities across the world showing that the median solar extended driving range is 18 and 8 km/day/kWp for driving and parked vehicles, respectively. The most favourable geographies include Africa, the Middle East and Southeast Asia; nonetheless, solar-powered mobility has relevant potential across the full sample, including China, Europe, North America and Australia.HighlightsUrban VIPV potential is assessed for 100 cities across the world.Solar extended driving range varies between 11 and 29 km/day/kWp.Charging frequency ratio ranges from 0% to 80%, with a median of 57%.Urban shadowing reduces driving range by about 25% for driving vehicles.Solar-powered vehicles have the potential to reduce CO2 emissions, operational costs and charging frequency needs of electric vehicles. This potential will depend on the local solar irradiation but also shadowing conditions, a relevant issue for urban contexts. The potential of solar-powered vehicles in the urban context is modelled for 100 cities across the world.image
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Electric vehicles (EVs) have the advantage of being resilient to natural disasters. However, users hesitate to donate electricity when they lose the chance to recharge at the utility. Solar electric vehicles (SEVs) save energy thr...
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Electric vehicles (EVs) have the advantage of being resilient to natural disasters. However, users hesitate to donate electricity when they lose the chance to recharge at the utility. Solar electric vehicles (SEVs) save energy through vehicle-integrated photovoltaics (VIPV) and make it possible to voluntarily donate excess energy, thus maintaining facility resilience. Given that the supply of solar energy to VIPV systems is not continuous and is difficult to forecast, the contribution of VIPV to the resilience of the larger energy system has been called into question. This is the first study in which the potential of VIPV to maintain utility resilience is investigated in the context of physical factors, such as irradiance, and social factors. The actual energy yield of a VIPV car was determined using an advanced 3D solar irradiation model under a nonuniform shading distribution, with validation from actual measures of solar irradiance on five orthogonal sides of the car body. The Monte Carlo method was used to model the complex factors in VIPV energy storage and energy donations under different scenarios. Depending on the climate, population density, and shading environment, the voluntary contribution of stored electricity in SEV is sufficient to provide disaster relief support.
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The EU crystalline silicon (c‐Si) PV manufacturing industry has faced strong foreign competition in the last decade. To strive in this competitive environment and differentiate itself from the competition, the EU c‐Si PV manufac...
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The EU crystalline silicon (c‐Si) PV manufacturing industry has faced strong foreign competition in the last decade. To strive in this competitive environment and differentiate itself from the competition, the EU c‐Si PV manufacturing industry needs to (1) focus on highly performing c‐Si PV technologies, (2) include sustainability by design, and (3) develop differentiated PV module designs for a broad range of PV applications to tap into rapidly growing existing and new markets. This is precisely the aim of the 3.5?years long H2020 funded HighLite project, which started in October 2019 under the work program LC‐SC3‐RES‐15‐2019: Increase the competitiveness of the EU PV manufacturing industry. To achieve this goal, the HighLite project focuses on bringing two advanced PV module designs and the related manufacturing solutions to higher technology readiness levels (TRL). The first module design aims to combine the benefits of n‐type silicon heterojunction (SHJ) cells (high efficiency and bifaciality potential, improved sustainability, rapidly growing supply chain in the EU) with the ones of shingle assembly (higher packing density, improved modularity, and excellent aesthetics). The second module design is based on the assembly of low‐cost industrial interdigitated back‐contact (IBC) cells cut in half or smaller, which is interesting to improve module efficiencies and increase modularity (key for application in buildings, vehicles, etc.). This contribution provides an overview of the key results achieved so far by the HighLite project partners and discusses their relevance to help raise the EU PV industries' competitiveness. We report on promising high‐efficiency industrial cell results (24.1% SHJ cell with a shingle layout and 23.9% IBC cell with passivated contacts), novel approaches for high‐throughput laser cutting and edge re‐passivation, module designs for BAPV, BIPV, and VIPV applications passing extended testing, and first 1‐year outdoor monitoring results compared with benchmark products.
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? 2023 The AuthorsThe vehicle integrated photovoltaic (VIPV) technology, which consists in integrating PV solar panels in the surfaces of electric vehicles, is a promising technology to increase car autonomy. Free-form curved PV s...
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? 2023 The AuthorsThe vehicle integrated photovoltaic (VIPV) technology, which consists in integrating PV solar panels in the surfaces of electric vehicles, is a promising technology to increase car autonomy. Free-form curved PV surfaces are demanded to meet the specific design constraints of the automotive. The proper characterization of three dimensional PV surfaces requires specific methods and equipment that must be developed. This paper describes the design principles and requirements of a solar simulator for characterization of curved PV modules. Its effectiveness is demonstrated by means of ray-tracing simulations, the results show the advantages provided by the use of a collimated light source in comparison to the conventional solar simulators used for flat modules. The light beam divergence of a non-collimated light source produces a non-uniformity boost between 2% and 20% depending on the module size and curvature. The module performance will be affected by this non-uniform irradiance, but the performance loss will also depend on specific characteristics of the module such as curvature, number and size of cells, series/parallel electrical connection and number of by-pass diodes. On the contrary, the proposed collimated solar simulator reproduces the solar illumination profile over the curved surface. The Helios 3198, a solar simulator with collimated light developed for concentrator modules, has been adapted accordingly to the design proposed. A module of 1 m of curvature has been tested, the short-circuit current of the cells follows the ideal cosine response of the curvature, differences are lower than 0.5% which proves the quality of the collimated beam.
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Abstract Vehicle integrated photovoltaic (VIPV) systems have much different requirements on maximum power tracking compared to stationary setups. The occurrence of fast changes between full irradiance and shading are demanding. To...
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Abstract Vehicle integrated photovoltaic (VIPV) systems have much different requirements on maximum power tracking compared to stationary setups. The occurrence of fast changes between full irradiance and shading are demanding. To evaluate the specific impact of these conditions on the specifications of VIPV systems, we conduct high resolution measurements of the incident irradiance onto a car body while driving. We investigate the influence of environmental conditions like weather, season and building density in an urban environment on measured irradiance on the roof and the sides of a vehicle. We find that weather conditions have the highest impact on the measured irradiance on the roof, while the relative irradiance on the side depends more heavily on the season. We also find that changes in irradiance occur predominantly at frequencies below 1?Hz, but changes with 100?Hz or more can occur in certain situations, with a tendency toward higher frequencies for sunny weather. This must be considered in maximum power point tracker design.
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An a-Si:H (p) window layer is used in silicon heterojunction (SHJ) solar cells; however, it is limited by short-circuit current density (J(SC)). In general, an emitter with a high doping concentration is appropriate for contact wi...
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An a-Si:H (p) window layer is used in silicon heterojunction (SHJ) solar cells; however, it is limited by short-circuit current density (J(SC)). In general, an emitter with a high doping concentration is appropriate for contact with a transparent conducting oxide (TCO); however, it is influenced by side effects such as a reduction of J(SC) through optical absorption. The conductivity of the emitter is lowered as its doping concentration is reduced, resulting in a decrease in V-OC and FF. We investigated p-type emitters such as those made of a-Si:H, a-SiC:H, and mu c-SiO:H through film analysis and AFORS-HET simulation to improve the conversion efficiency of the device. Prior to conducting a simulation, a fabricated SHJ solar cell was used to theoretically calculate the precise parameter values. The obtained efficiency was 22.03 % when V-OC=730 mV, J(SC)=39.63 mA/cm(2), and FF = 76.13 %. Based on the fitted structure, we conducted experiments to test the emitter materials within a wide band gap and performed a simulation. In the case of mu c-SiO:H (p), the achieved efficiency was 24.23 % when V-OC=736.6 mV, J(SC)=40.15 mA/cm(2), and FF = 81.93 %.
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Vehicle integrated photovoltaics (VIPV) are among the identified solutions to reduce the environmental impacts of the transport sector. The model developed here simulates the VIPV system. It considers various usage patterns and ve...
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Vehicle integrated photovoltaics (VIPV) are among the identified solutions to reduce the environmental impacts of the transport sector. The model developed here simulates the VIPV system. It considers various usage patterns and vehicle types, several characteristics of the photovoltaic system and all the losses that may decrease energy yield. Focusing on a passenger car, simulations indicate the order of influence of the parameters on the outputs of the model: geographic locality, shading, thresholds due to extra-consumption needed to charge the vehicle's battery from the photovoltaic (PV) system and occurrence of recharge with the grid. With technology projections for 2030, with 30% shading, VIPV will cover a distance of up to 1444 km per year. This represents up to 12% of the driven mileage. For the best month, it can reach up to 14 km/day. For average Europe and realistic conditions, VIPV cover 648 km per year. Life cycle assessment (LCA) of a solarized passenger car shows a negative balance for a low-carbon electricity mix and average solar irradiance. In favorable conditions, the carbon footprint is up to 489 kg of CO2-equivalent avoided emissions on a 13-year lifespan. Beyond the focus on km and LCA, VIPV may provide useful functions in non-interconnected zones and for resilience in disaster areas.
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For a viable and commercial attractive integration of vehicle integrated photovoltaic applications (ViPVs) energy forecasting is required as a foundation for business case calculation. The developed algorithm facilitates the forec...
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For a viable and commercial attractive integration of vehicle integrated photovoltaic applications (ViPVs) energy forecasting is required as a foundation for business case calculation. The developed algorithm facilitates the forecast of annual power distribution and solar energy yield along any given track tested on a German use case. A high temporal and spatial resolution of the meteorological database providing ambient temperature, wind speed, and global horizontal irradiance was determined as a necessity to preserve the irradiance distribution and consequently the power distribution available throughout the year. For ViPV module temperature, respectively, module efficiency benefits strongly from head wind. As a consequence, the performance of ViPV under motion was identified as superior to non-mobile PV installations. The potential annual energy yield of the three showcasing commercial semi-trailer lorries operating in Germany is identified to be 3-7 MWh depending on the used cell technology. The potential energy gain due to head wind cooling is estimated to be 20-75 kWh per trailer and year. Copyright (C) 2017 John Wiley & Sons, Ltd.
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