Determination and evaluation of a backsheet’s intrinsic reflectance

McIntosh, Keith R.; Jung, J.J.; Abbott, Malcolm; Sudbury, Benjamin A.

doi:10.1063/1.5049257

Cited by 7 publications

(4 citation statements)

References 13 publications

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“…In this way, the module operated similarly to a monofacial module with a white back sheet. In fact, the white cardboard here used has a low transmittance in the infrared range while, in some cases, the infrared white back sheets transmittance can be quite large [15], which would likely imply a better thermal behaviour of the module.…”

Section: Methodsmentioning

confidence: 99%

The Effects of Module Temperature on the Energy Yield of Bifacial Photovoltaics: Data and Model

Leonardi,

Corso,

Milazzo

et al. 2021

Energies

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Bifacial photovoltaics (BPVs) are emerging with large momentum as promising solutions to improve energy yield and cost of PV systems. To reach its full potential, an accurate understanding of the physical characteristics of BPV technology is required. For this reason, we collected experimental data to refine a physical model of BPV. In particular, we simultaneously measured the module temperature, short circuit current (Isc), open-circuit voltage (Voc), power at the maximum power point (Pmpp), and the energy yield of a bifacial and a monofacial minimodule. Such minimodules, realised with the same geometry, cell technology, and module lamination, were tested under the same clear sky outdoor conditions, from morning to afternoon, for three days. The bifacial system experimentally shows higher module temperatures under operation, about 10 °C on a daily average of about 40 °C. Nevertheless, its energy yield is about 15% larger than the monofacial one. We propose a physical quantitative model that fits the experimental data of module temperature, Isc, Voc, Pmpp, and energy yield. The model was then applied to predict the annual energy yield of PV module strings. The effect of different PV module temperature coefficients on the energy yield is also discussed.

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Section: Methodsmentioning

confidence: 99%

The Effects of Module Temperature on the Energy Yield of Bifacial Photovoltaics: Data and Model

Leonardi,

Corso,

Milazzo

et al. 2021

Energies

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“…Web application-based Sunsolve TM simulation tool evaluates the optical response in loss (gain) in the various solar cell regions under standard illumination sources. Photo-generated current generated inside the solar cell and collected by the p–n junction ( J L ) is calculated following (Equation (2)) employing a combination of a complex algorithm of Monte-Carlo’s ray-traced algorithm method and thin-film optics [ 42 ]:

where J ph (λ) is the incident photon current as determined from photonic flux incident light density, A(λ) is the fraction of the incident light that becomes absorbed by the active region of the solar cell as determined by raytracing, and η(λ) is the collection efficiency within that active region. The detail of all parameters is followed as per the literature [ 39 ].…”

Section: Methodsmentioning

confidence: 99%

“…Web application-based Sunsolve TM simulation tool evaluates the optical response in loss (gain) in the various solar cell regions under standard illumination sources. Photo-generated current generated inside the solar cell and collected by the p-n junction (J L ) is calculated following (Equation ( 2)) employing a combination of a complex algorithm of Monte-Carlo's ray-traced algorithm method and thin-film optics [42]:…”

Section: Methodsmentioning

confidence: 99%

Raytracing Modelling of Infrared Light Management Using Molybdenum Disulfide (MoS2) as a Back-Reflector Layer in a Silicon Heterojunction Solar Cell (SHJ)

et al. 2022

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The silicon heterojunction solar cell (SHJ) is considered the dominant state-of-the-art silicon solar cell technology due to its excellent passivation quality and high efficiency. However, SHJ’s light management performance is limited by its narrow optical absorption in long-wave near-infrared (NIR) due to the front, and back tin-doped indium oxide (ITO) layer’s free carrier absorption and reflection losses. Despite the light-trapping efficiency (LTE) schemes adopted by SHJ in terms of back surface texturing, the previous investigations highlighted the ITO layer as a reason for an essential long-wavelength light loss mechanism in SHJ solar cells. In this study, we propose the use of Molybdenum disulfide (MoS2) as a way of improving back-reflection in SHJ. The text presents simulations of the optical response in the backside of the SHJ applying the Monte-Carlo raytracing method with a web-based Sunsolve high-precision raytracing tool. The solar cells’ electrical parameters were also resolved using the standard electrical equivalent circuit model provided by Sunsolve. The proposed structure geometry slightly improved the SHJ cell optical current density by ~0.37% (rel.), and hence efficiency (η) by about 0.4% (rel.). The SHJ cell efficiency improved by 21.68% after applying thinner back ITO of about 30 nm overlayed on ~1 nm MoS2. The efficiency improvement following the application of MoS2 is tentatively attributed to the increased NIR absorption in the silicon bulk due to the light constructive interface with the backside components, namely silver (Ag) and ITO. Study outcomes showed that improved SHJ efficiency could be further optimized by addressing front cell components, mainly front ITO and MoS2 contact engineering.

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“…The spectral reflectance of the backsheet weighted by the photon flux density of the AM1.5 spectrum is 84%. Note that the interface reflectance measured in air is different from the encapsulant-backsheet interface [9]. In order to quantify experimentally the extra light recollected by cells placed at the edges and corners of modules, test modules with individually connected cells are fabricated.…”

Section: Methodsmentioning

confidence: 99%

Reassessment of cell to module gains and losses: Accounting for the current boost specific to cells located on the edges

Dupré¹,

Levrat²,

Champliaud³

et al. 2018

AIP Conference Proceedings

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The power produced by a photovoltaic module is not simply the sum of the powers of its constituents cells. The difference stems from a number of so-called "cell-to-module" (CTM) gain or loss mechanisms. These are getting more and more attention as improvements in cell efficiency are becoming harder to achieve. This work focuses on two CTM mechanisms: the gain due to the recapture of light hitting the apparent backsheet in the "empty" spaces around the cells and the loss from the serial connection of "mismatched" cells i.e. with different maximum power points. In general, for insulation purposes, the spaces on the edges of modules are larger than the spacing between cells. This study reveals that, when reflective backsheets are used, these "edge spaces" provide an additional current boost to the cells placed at the edges that can lead to a 0.5% gain in the output power of modules (with 60 or 72 cells). This location-dependent current boost adds to the usual variations in cell characteristics dictated by the binning size and results in larger "cell-to-cell mismatch losses". However, the simulations reveal that for short-circuit current bin size smaller than 5%, this additional mismatch loss is lower than 0.05%. All considered, this study demonstrates that the spaces at the edges of PV modules have a significant impact on the cell to module ratios (≈+0.5%abs or ≈16% of the CTM gains) when reflective backsheets are used.

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Determination and evaluation of a backsheet’s intrinsic reflectance

Cited by 7 publications

References 13 publications

The Effects of Module Temperature on the Energy Yield of Bifacial Photovoltaics: Data and Model

The Effects of Module Temperature on the Energy Yield of Bifacial Photovoltaics: Data and Model

Raytracing Modelling of Infrared Light Management Using Molybdenum Disulfide (MoS2) as a Back-Reflector Layer in a Silicon Heterojunction Solar Cell (SHJ)

Reassessment of cell to module gains and losses: Accounting for the current boost specific to cells located on the edges

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