An optical comparison of silicone and EVA encapsulants under various spectra

Abstract

Under the AM1-5g spectrum, the efficiency of a c-Si module can be increased by 0.5-1.5% (relative) by using a silicone encapsulant rather than EVA. This increase is primarily due to photons of wavelengths less than -400 nm being transmitted by silicone but blocked by EVA. The highest increase in efficiency arises for cells with a good 'blue response' and for silicones of a higher refractive index. In this work we show that when calculated for the AM1-5g spectrum, the optical advantage of silicone over EVA tends to be an underestimate of what can be expected in the field. This is because incident spectra are frequently 'bluer' than the AM1-5g spectrum, particularly in summer and on cloudy days. In such cases, a larger fraction of photons have a wavelength less than 400 nm. With ray tracing, we find that the relative advantage of silicone over EVA is increased by an additional 0.3% on a sunny summer day in Phoenix AZ., and by 0.7% on a cloudy summer day in Brownsville TX. Still greater increases are expected for maritime climates and for installations with high albedo.

Finding 10% hidden electricity in crystalline Si solar cells using PDMS coating and three‐dimensional cell arrays

“…Although the encapsulation film shows some optical gain due to internal reflection of scattered light from the surface of the textured solar cells, it causes a large amount of optical loss by cutting off short wavelength light. Furthermore, by absorption of high energy short wavelength light, it suffers from a browning effect during long operation periods . In addition, the flat panel structures are only designed for standard characterization conditions, which do not fully reflect actual operation conditions, especially when they are used in urban applications.…”

“…Over the past few decades, the crystalline silicon (Si) solar cell industry has matured and photovoltaics is now considered a key aspect of renewable energy production. 1,2 This development has led to the continuous improvement of crystalline Si solar cells from back surface field structures (BSF) to passivated emitter and rear contact (PERC), [3][4][5] tunneling oxide passivated contact (TOPCon), [6][7][8][9] interdigitated back contact (IBC), [10][11][12][13] and heterojunction intrinsic thin layer (HIT) solar cells [14][15][16] as well as enhanced light trapping structures such as surface texturing 1,2,17,18 and cello structured grids. 19 With this development, the efficiency of crystalline Si solar cells has been increased to 26.7% at the lab-scale by HIT-IBC cells.…”

“…Furthermore, by absorption of high energy short wavelength light, it suffers from a browning effect during long operation periods. 17,18,[25][26][27][28][29][30][31] In addition, the flat panel structures are only designed for standard characterization conditions, which do not fully reflect actual operation conditions, especially when they are used in urban applications. We suggest a new concept to overcome these limitations.…”

Vertical bifacial solar farms: Physics, design, and global optimization

“…We assume η = 18.9% and η diff = 15.67% under normal and diffuse illumination on a single face of the panel (estimated using the simulator 'Tracey' [39,40,41]: see Supplementary Information (SI)). Oblique angles in the diffuse light have higher reflection loss than normal incidence-that is why η diff < η.…”

Assessment of the Performance and Defect Investigation of PV Modules after Accelerated Ageing Tests

“…The study of degradation and failure mechanisms in PV modules is often based on accelerated ageing tests (AAT), where failure effects are reproduced and quantified [11][12][13][14][15][16][17]. If it is assumed that characterization and monitoring methods, such as I-V measurements and infrared thermography (IRT), are already established means of defect detection and diagnosis, the strong need for prognosis and long-term reliability gives the impetus of further research.…”