Encapsulation of Solar Cells for Damp Heat Test

Moisture-barrier backsheet stack for photovoltaic modules that provides reliable protection against moisture ingress over the long term to increase module lifetime. The stack includes an outer UV protective layer, an inner adhesion layer, barrier layers, and reinforcing layers. The barrier layers form a sealing layer between the UV and adhesion layers to block moisture diffusion. The reinforcing layers provide mechanical stability. The barrier layers prevent moisture gradients from forming, equalizing moisture levels across the stack over time.

Source

Photoelectric conversion element with improved sealing layers for high-temperature and high-humidity environments. The element comprises a photoelectric conversion layer, conductive layer, first sealing layer of inorganic metal oxide, nitride, oxynitride, or fluoride, and second sealing layer of polymer or nitride coating. The inorganic first sealing layer prevents oxygen and atomic oxygen penetration, while the second sealing layer provides additional protection against environmental degradation.

Source

A method for preparing solar cell modules with improved packaging performance, comprising: providing a substrate with a solar cell group and a sealant layer surrounding the group; creating an exhaust groove in the sealant layer; incorporating an air vent on the solar cell group; laminating the structure; heating the laminate while exhausting the sealant layer through the groove; and immediately laminating the structure after heating.

Source

A photovoltaic module with improved long-term reliability, comprising a transmissive front protective layer, a back protective layer, a plurality of solar cells, and a filler material that generates a free acid. The filler material is positioned between the front protective layer and the solar cells, and the front protective layer has microthrough-holes that allow moisture to reach the filler material while preventing water ingress into the module.

Source

The development of perovskite solar cells (PSCs) has ushered in a new era of solar technology, characterized by its exceptional efficiency and cost-effective production. However, the soft and fragile nature of perovskites makes module encapsulation challenging. Polyolefin elastomers (POEs) have been reported to be promising encapsulants for perovskite modules. However, little research exists on identifying criteria among different types of POEs as encapsulants. Here, two POEs with different morphologies were compared as encapsulants. The first POE crystallizes during encapsulation (crystal content 40%), and the resulting shrinkage or warpage leads to delamination, causing minimodule failure. In contrast, perovskite minimodules encapsulated with a mostly amorphous POE exhibited better reliability and reproducibility. The best perovskite minimodules passed the thermal cycling test for 240 cycles between 40 and 85 C and the damp heat test for 1419 h, according to the IEC 61215 standard. This study highlights the importance of the morphology of encapsulants in achieving high-quality e... Read More

Source

Abstract Perovskite solar cells promise to be part of the future portfolio of photovoltaic technologies, but their instability is slow down their commercialization. Major stability assessments have been recently achieved but reliable accelerated ageing tests on beyond small-area cells are still poor. Here, we report an industrial encapsulation process based on the lamination of highly viscoelastic semi-solid/highly viscous liquid adhesive atop the perovskite solar cells and modules. Our encapsulant reduces the thermomechanical stresses at the encapsulant/rear electrode interface. The addition of thermally conductive two-dimensional hexagonal boron nitride into the polymeric matrix improves the barrier and thermal management properties of the encapsulant. Without any edge sealant, encapsulated devices withstood multifaceted accelerated ageing tests, retaining >80% of their initial efficiency. Our encapsulation is applicable to the most established cell configurations (direct/inverted, mesoscopic/planar), even with temperature-sensitive materials, and extended to semi-transparent ce... Read More

Source

Abstract There is a significant deficiency in perovskite solar module (PSM) stability under thermomechanical stressors which is not well-understood. In this perspective, common issues seen with perovskite solar cell device fabrication related to thermomechanical reliability of PSM processing are discussed, with a focus on how the robustness of device layers and interlayer adhesion can be improved. Film stresses, adhesion of charge transport layers, and instability under light and heat are discussed with the purpose of providing insight on designing PSMs for durability. Processing conditions of encapsulation of PSMs and critical parameters to consider are also examined, and accelerated testing protocols for PSMs are discussed that probe mechanical degradation modes and ensure reliability of devices in the field.

Source

A solar cell with enhanced damp heat resistance, comprising a semiconductor substrate with a fine grid layer, a dielectric protection layer, and a busbar layer. The busbars penetrate through the dielectric protection layer and connect with the fine grids. The dielectric protection layer is formed between the fine grid layer and the busbar layer to prevent moisture and heat from reaching the fine grid layer, thereby enhancing the solar cell's resistance to damp heat aging.

Source

Abstract For commercial applications, Perovskite Solar Cells (PSCs) need to be well encapsulated to improve long term stability. The most common method, glass-glass encapsulation, uses edge sealant materials to encapsulate the device between sheets of glass. Glass-Glass encapsulation, while providing provide adequate protection from the ambient environment, limits the use of flexible substrates for thin film solar cells due to its rigidity. Additionally, the added weight of glass encapsulation reduces the specific power (W kg 1 ) of PSCs, which is an important factor when designing solar cells for aerospace applications. Here we demonstrate that commercially available acrylic spray encapsulation offers efficient and robust stability for PSCs. It is shown that applying the encapsulation via this method does not degrade the PSCs, unlike other literature and glass-glass encapsulation methods. Additionaly, it is shown that 1 coat of acrylic spray encapsulation has an effective thickness of 1.77 m and a weight of 6 mg. For stability measurements, PSCs with an acrylic coating show a 4... Read More

Source

Abstract This paper particularly explains potential-induced degradation (PID) of wafer-based standard p-type crystalline silicon technology. We present a single-encapsulation method that is useful for simulating PID in the laboratory to facilitate microanalyses of module-level solar cells. The PID testing is performed for the module with single-encapsulation and conventional modules. Their currentvoltage characteristics and electroluminescence images are investigated before and after the PID tests. As described herein, we infer that the single-encapsulation modules generate PID almost in the same way as conventional modules do, and that the degradation trend is almost identical to that of conventional modules. Results of PID recovery tests indicate that the time necessary for PID recovery is always less than that for PID generation, irrespective of the encapsulation method.

Source

A barrier assembly for photovoltaic devices comprising a barrier film and a polyurethane outer protective film layer bonded directly to the barrier film's exposed surface. The barrier film is a flexible, transparent layer comprising an inorganic oxide layer sandwiched between two polymer layers, while the polyurethane outer protective film layer provides additional protection against environmental factors such as UV radiation, moisture, and air infiltration. The assembly is suitable for protecting a wide range of photovoltaic devices, including organic photovoltaic devices, thin-film solar cells, perovskite solar cells, and dye-sensitized solar cells.

Source

Purpose Solar cells could make textile-based wearable systems energy independent without the need for battery replacement or recharging; however, their laundry resistance, which is prerequisite for the product acceptance of e-textiles, has been rarely examined. This paper aims to report a systematic study of the laundry durability of solar cells embedded in textiles. Design/methodology/approach This research included small commercial monocrystalline silicon solar cells which were encapsulated with functional synthetic textile materials using an industrially relevant textile lamination process and found them to reliably endure laundry washing (ISO 6330:2012). The energy harvesting capability of eight textile laminated solar cells was measured after 1050 cycles of laundry at 40 C and compared with light transmittance spectroscopy and visual inspection. Findings Five of the eight textile solar cell samples fully maintained their efficiency over the 50 laundry cycles, whereas the other three showed a 20%27% decrease. The cells did not cause any visual damage to the fabric. The result ... Read More

Source

The degradation behaviors of the encapsulant and the imbedded additives significantly determine the reliability of solar modules. Nevertheless, a link between the degradation of the encapsulant, including the additive interactions, and the longevity of the overall module is rarely established until now. Herein, minimodules containing ethylenevinyl acetate copolymer (EVA) as encapsulant are subject to damp heat (DH) or ultraviolet (UV) weathering based on IEC 61215. Macroscopically, the degradation under both weathering types characterized by I V measurements and electroluminescence (EL) measurements is diverging in dependence on the used stressor. Using electron paramagnetic resonance and orbitrap mass spectrometry, it is shown that deacetylation of the EVA occurs significantly for both types of weathering. In the case of DH, however, the mechanism of action of the UV stabilizer is hindered, so that strong encapsulant degradation is observed despite a lower energy input in comparison with UV. Furthermore, the produced acetic acid under DH weathering leads to the observed reductio... Read More

Source

The development of a reliable encapsulation is a key factor for protecting perovskite solar cells from extrinsic degradation and an important step to commercialization. The use of edge sealing materials has already been proven effective for rigid substrates. However, for flexible devices, a different encapsulation strategy must be developed. In this study, epoxy- and acrylic-based adhesives were tested over blade-coated p-i-n MAPI devices and the encapsulation was evaluated with currentvoltage measurements, calcium, and thermal stability tests. Although causing discoloration around the cells, over the area without the evaporated top electrode, the epoxy adhesive showed great performance after encapsulation and under thermal stress. This strategy was used to compare the stability of PEDOT:PSS and NiO as HTL. After an initial drop of 40 % in performance, the device with NiO was stable for over 5500 h under 85 C. These results show that this method can be used for evaluating the stability of perovskite solar cell and that, with further development of a proper buffer layer, epoxy-based... Read More

Source

Lightweight modules are essential for next-generation vehicle-integrated photovoltaic (VIPV) applications, such as solar-powered cars, allowing integration of solar cells beyond the roof, and on the hood, boot and body panels, and thereby extending the driving range. However, the lightweight module's reliability and corresponding degradation mechanisms under various environmental stresses are less researched. In this work, we investigate interconnection and encapsulation strategies to improve reliability against damp heat and mechanical impact. We fabricated lightweight mini modules, weighing around 3.45 kg/m2, and conducted hail impact and damp heat tests. These tests result in different failures, such as cracks in the solar cell, module delamination, and microcracks in the backsheet. By carrying out failure mechanism analysis and altering the fiber reinforcement in backsheet and encapsulation materials, we can increase resilience to these failure modes, thus providing guidance for the design of lightweight PV modules for next-generation VIPV.

Source

A bilayer polymer encapsulation strategy is used to improve the perovskite solar cells stability under high humidity conditions (80 5% RH).

Source

Enhancing the lifetime of perovskite solar cells (PSCs) is one of the essential challenges for their industrialization. Although the external encapsulation protects the perovskite device from the erosion of moisture and oxygen under various harsh conditions. However, the perovskite devices still undergo static and dynamic thermal stress during thermal and thermal cycling aging, respectively, resulting in irreversible damage to the morphology, component, and phase of stacked materials. Herein, the viscoelastic polymer polyvinyl butyral (PVB) material is designed onto the surface of perovskite films to form flexible interface encapsulation. After PVB interface encapsulation, the surface modulus of perovskite films decreases by nearly 50%, and the interface stress range under the dynamic temperature field (40 to 85 C) drops from 42.5 to 64.8 MPa to 14.8 to 5.0 MPa. Besides, PVB forms chemical interactions with FA + cations and Pb 2+ , and the macroscopic residual stress is regulated and defects are reduced of the PVB encapsulated perovskite film. As a result, the optimized device's ... Read More

Source

In the current work, we have employed an easy, simple, and cost-effective encapsulation process to enhance the lifespan of solar cells when exposed to challenging outdoor conditions. A solar cell was encapsulated using the liquid phase of a polyurethane elastomer prepared from low-cost vegetable castor oil, employing the simple and easy one-shot process with 2,4-toluene diisocyanate (TDI), and without the use of chain extenders. Optical transmission measurements revealed that the transparency of the encapsulant in the visible region reached 92 % with increasing TDI concentration, while the transparency was blocked in the ultraviolet (UV) region. Through the present work, the performance parameters of the solar cell have been enhanced after encapsulation with polyurethane under different compositions and thicknesses. The polyurethane encapsulant did not retain the applied temperature in the range of 30150 C, but rather transferred the heat outside the solar cell. We can conclude that the low-cost and easily prepared polyurethane is suitable for solar cell encapsulation in various en... Read More

Source

For the commercialization of perovskite solar cells (PSCs), detection of associated degradation mechanisms and mitigation of their effect is of paramount importance. The former requires outdoor and indoor stability tests to detect these mechanisms under real operation conditions and to accelerate them under controlled environments. Herein, the thermomechanical stability of encapsulated PSCs in outdoor tests at three locations coupled with indoor thermal cycling tests is investigated. Results show that encapsulantinduced partial delamination can occur in outdoor and indoor tests, leading to disruption in device integrity and substantial loss in the cell active area and shortcircuit current. The findings suggest that delamination involves C 60 and SnO 2 layers as the mechanically weakest point in the device stack. To the best of our knowledge, this work is the first demonstration of delamination in encapsulated PSCs under real operation conditions. While partial delamination emerged on some of the cells exposed in Israel and Cyprus in just a few weeks, it did not occur in Germany ove... Read More

Source

Abstract The delamination of encapsulants in photovoltaic (PV) modules is a common issue that leads to power loss due to optical losses. Encapsulant debonding is usually examined under monotonic loading conditions subsequent to environmental exposure such as damp heat. Servicerelevant, superimposed environmentalmechanical fatigue loads are not considered adequately. Hence, the environmental fatigue delamination resistance of thermally toughened double glass laminates with an ethylene vinyl acetate copolymer (EVA) adhesive layer was investigated in this study. Focus was given to the melting range of EVA, in which the noncrosslinked crystalline phase fraction is already in the partly molten state. Double cantilever beam specimens were tested on an electrodynamic test machine at temperatures of 60, 70, 80, and 90C and relative humidity (rh) levels of 2%, 30%, 50%, and 80%. The fractured surfaces were characterized by digital microscopy, Fourier transform infrared spectroscopy (FTIR), Xray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC). The cyclic fati... Read More

Source

At present, the care of the environment as well as the use of solar energy are of great importance. One way to use solar energy for clean energy generation is through the use of photovoltaic modules. The performance of the crystalline silicon PV module is mainly determined by the efficiency of the silicon cells, but the properties of the other components, such as the encapsulant material, also have a high impact. The objective of this study was to evaluate the adherence of Thermoplastic Polyurethane (TPU) as an alternative material for the protection of solar cells, since the encapsulating material most used in solar production to date is Ethylene vinyl acetate (EVA) and it serves as a comparison of possible advantages and disadvantages. The tests carried out were in accordance with the International IEC 61215 and 61345 Standards. The adhesion results were sufficiently good and without optical defects. It is concluded that TPU can be used as an alternative material for encapsulating solar cells.

Source

The performance loss caused by encapsulation has been an obstacle to guarantee the excellent power conversion efficiency of perovskite solar cells (PSCs) in practical application. This work revealed that the encapsulation-induced performance loss is highly related to the tensile strains imposed on the functional layers of the device when the PSC is exposed directly to the deformed encapsulant. A barrier strategy is developed by employing a nonadhesive barrier layer to isolate the deformed encapsulant from the PSC functional layer, achieving a strain-free encapsulation of the PSCs. The encapsulated device with a barrier layer effectively reduced the relative performance loss from 21.4% to 5.7% and dramatically improved the stability of the device under double 85 environment conditions. This work provides an effective strategy to mitigate the negative impact of encapsulation on the performance of PSCs as well as insight into the underlying mechanism of the accelerated degradation of PSCs under external strains.

Source

Perovskite solar cells (PSCs) are among the most promising emerging photovoltaic technologies, due to their high efficiency, comparable to that of silicon solar cells. However, concerns about the stability of these devices remain, despite great progress achieved in recent years. To address these concerns, comprehensive investigations of their stability under realistic operating conditions are necessary. In this Perspective, we will discuss the outdoor testing of PSCs. We will first introduce degradation mechanisms relevant for intrinsic stability, as well as degradation mechanisms due to ambient exposure. Effective encapsulation of PSCs will then be discussed, followed by a summary of achieved progress and discussion of testing protocols and equipment to make outdoor testing more accessible. Finally, challenges and future outlook will be discussed.

Source

Abstract We investigated the long-term durability of our newly developed encapsulant-less p-type crystalline silicon (c-Si) photovoltaic (PV) modules, with a base made of polycarbonate (PC), against potential-induced degradation (PID) in dry and damp-heat (DH) environments. Encapsulant-less modules were found to have high PID resistance compared to conventionally encapsulated c-Si PV modules in both PID conditions. We observed a slight PID for the encapsulant-less modules in which the cover glass was in contact with the solar cell. The slight PID can be suppressed by using a base with a deeper groove so that a sufficient gap between the cover glass and the cell is prepared. Yellow precipitates were formed in the encapsulant-less modules in the DH environment. This is probably due to the hydrolysis of the PC, and proper measures to prevent the precipitate formation should be applied for the industrialization of the encapsulant-less modules.

Source

The degradation behavior of solar modules was investigated under combined damp heat and UV weathering conditions. A full electrical characterization, including electro luminescence measurements, shows a severe module degradation after 2000h, with power losses exceeding 60%. A chemical analysis of the encapsulation material on the basis of ethylene-vinyl acetate copolymer, extracted directly from the weathered modules, reveals a clear dependence of the encapsulant degradation on the position in the module and the weathering time. Remarkably, the consumption of the UV stabilizer in the encapsulant correlates to the degradation of the encapsulation material and finally to the degradation of the solar module. This finding emphasizes the relevance of the quality control of the encapsulant formulation for the module reliability.

Source

Photovoltaic modules with glass/glass configuration can overcome some problems typical of glass/polymer backsheet modules by limiting, for instance, moisture ingress. However, it is necessary to adapt the bill of materials to extend the lifetime of glass/glass PV modules and to improve their reliability. The application of an edge seal and the use of encapsulants alternative to ethylene vinyl acetate might reduce the issues connected to humidity ingress and acetic acid production during exposure in the field. This study is focused on the analysis of the performance of test coupons laminated with four different encapsulants and exposed to damp heat test.

Source

The typical solar module has numerous drawbacks when used for extended periods of time in environmental conditions. Examples include cracked cells, interconnection failure, and decreasing output power. Also, it cannot be repaired; once a fault occurred in one cell, the module must be replaced. The proliferation of unused solar panels has become an issue due to the vast increase in the use of solar energy resources. While the current focus of solar panel research is to increase production energy efficiency, solar panel repairability and recycling of end of life (EOL) panels is rarely considered. The management of the EOL panels can efficiently save natural resources and save production costs. This study explores conventional encapsulation methods and introduces a novel approach to solar panel design that allows for easy access to individual components, facilitating repairs, upgrades, and modifications. The experimental study demonstrates that when using the novel encapsulation method, illumination current voltage properties are unaffected. Furthermore, a thermal analysis is conducted ... Read More

Source

Efficient and lossless encapsulation must be resolved before the industrialization of monolithic perovskite/silicon tandem solar cells (PSTs). Here, an ultraviolet (UV) curable material, which is environmentally friendly and needs only 1 min of UV solidification, is designed and used to encapsulate three types of typical PSTs, namely, flat structure, special texture structure, and commercial texture structure. Since the cured encapsulating material has an appropriate refractive index similar to glass and has a nondestructive impact on the perovskite, the performance of encapsulated devices improves with the increase of current density. The device stability tests (including immersion in water and weak acid, outdoor exposure, 35C, and 60C/85RH% environment) demonstrated an initial efficiency of more than 90% after 1000 h. A 100 W PST power station is built by encapsulating PSTs with an expanded area (>10 cm2).

Source

Currently, the perovskite solar cells efficiency exceeds 20% at a rate of improvement that is unprecedented. This technique is indeed very promising because it is compatible with inexpensive solution processing. To be commercially viable, a thin-film solar device must pass the International Electrotechnical Commission (IEC) testing standards for environmental stability. Commercialization of perovskite solar cells is now restricted by lack of stability. The primary cause of this issue is the perovskite layer instability when exposed to moisture, light, and thermal variables. Nonetheless, it is crucial to investigate stability issues within device's layers and interfaces. Due to the interdependent relationships between the layers, including the charge transport layer, and electrodes, it is necessary to approach the device as a whole system in order to address the stability challenges described in this article. Future study should concentrate on strengthening the perovskites intrinsic stability, engineering the device shape, and identifying durable encapsulation materials that resolve ... Read More

Source

Long-term stability is a requisite for the widespread adoption and commercialization of perovskite solar cells (PSCs). Encapsulation constitutes one of the most promising ways to extend devices for lifetime without noticeably sacrificing the high power conversion efficiencies that make this technology attractive. Among encapsulation strategies, the most investigated methods are as follows: (1) glass-to-glass encapsulation, (2) polymer encapsulation, and (3) inorganic thin film encapsulation (TFE). In particular, the use of UV-, heat-, water-, and/or oxygen-resistant thin films to encapsulate PSCs is a new and promising strategy for extending devices for lifetime. Thin films can be deposited directly onto the PSC, as in TFE, or can be used in conjunction with glass-to-glass and polymer encapsulation to effectively prevent the photo-, thermal-, oxygen-, and moisture-induced degradation of the perovskite. This chapter will outline perovskite degradation mechanisms and provide a summary of the progress made to-date in the encapsulation of PSCs, with a particular focus on the most recent ... Read More

Source

Encapsulation engineering is an effective strategy to improve the stability of perovskite solar cells. However, current encapsulation materials are not suitable for lead-based devices because of their complex encapsulation processes, poor thermal management, and inefficient lead leakage suppression. In this work, we design a self-crosslinked fluorosilicone polymer gel, achieving nondestructive encapsulation at room temperature. Moreover, the proposed encapsulation strategy effectively promotes heat transfer and mitigates the potential impact of heat accumulation. As a result, the encapsulated devices maintain 98% of the normalized power conversion efficiency after 1000 h in the damp heat test and retain 95% of the normalized efficiency after 220 cycles in the thermal cycling test, satisfying the requirements of the International Electrotechnical Commission 61215 standard. The encapsulated devices also exhibit excellent lead leakage inhibition rates, 99% in the rain test and 98% in the immersion test, owing to excellent glass protection and strong coordination interaction. Our strateg... Read More

Source

The direct current bias for photovoltaic (PV) modules interconnected in series-strings may include both high voltage negative ("HV-") and positive ("HV+") polarity with respect to the electrical ground. Multiple degradation modes, resulting in quantifiable optical loss, were found to occur during HV-/HV+ sequential stress, including: corrosion of the external glass surface, encapsulant delamination (at its interfaces with the glass and the PV cell), internal haze formation (resulting from a chemical interaction between the glass and the encapsulant), corrosion and migration of the gridlines, and corrosion of the silicon nitride (SixNy) antireflective coating on the cell. The effects of these separate modes were examined using monolithic (e.g., glass or PV cell) and laminated-coupon (glass/encapsulant/glass or glass/encapsulant/cell/encapsulant/backsheet) specimens. Characterizations during and after unbiased accelerated testing at 85 degrees C/85% relative humidity included: spectrophotometry, optical microscopy, electron microscopy, and ellipsometry. For some module components (i.e.... Read More

Source

Abstract Due to the shortage of energy in the world, solar energy has received widespread attention as an inexhaustible new green energy and as one of the main sources of power. Many researchers have studied the various materials and efficiencies of solar cells; however, how to extend the life of solar cells has rarely been studied. At present, the main encapsulating method of solar cells is to seal their surface with films such as ethylene-vinyl acetate and polyvinyl butyral. The main problem that has been encountered is that the erosion of water and oxygen leads to a reduction in the service life and efficiency of solar cells. Inspired by the solar panels of satellites in space, a revolutionary vacuum-glazing encapsulating solution with zero H2O and O2 has been invented. The experimental results have nearly doubled the 3035-year service life of solar cells, based on deep learning predictions. Therefore, the building integrated photovoltaic can be used for the 70-year life of a building. The method is applicable to various solar cells, such as crystalline Si cells, CIGS, CdTe and p... Read More

Source

Effectively encapsulating perovskite solar cells (PSCs) to enhance the external reliability is the key towards commercialization. We herein propose a facile encapsulation method by introducing conductive ribbons and a polyethylene terephthalate (PET) backsheet on both sides of PSC. Via applying thermoplastic polyolefin (TPO) encapsulant, we implemented PSCs with fine encapsulation, enabling considerable durability in the ambient atmosphere and even with water immersion, demonstrating almost no degradation in the device output, which is ascribed to the low water vapor transmission rate as well as the high chemical stability of TPO. The operation reliability of the encapsulated cell is also significantly increased, maintaining 80% of the initial efficiency after 770 hours light illumination in an ambient atmosphere. This novel encapsulation route provides a feasible idea for the commercial application of PSCs in the future.

Source

Vacuum lamination encapsulation is widely adopted to prolong the duration of perovskite solar cells (PSCs) in real operation. However, additional encapsulant along with rigorous processing conditions leads to severe power conversion efficiency (PCE) loss to the corresponding devices. Herein, thermal and optical simulations and experiments are combined, to analyze the mechanisms for device failure during vacuum lamination. Singleglass encapsulation structure is proposed, which exhibits enhanced thermal conductivity, ensuring thorough and homogeneous melting of the encapsulant during the lamination process. This effectively mitigates delamination within the module and reduces parasitic photocurrent losses in the PSC device after encapsulation. Notably, the singleglass encapsulation devices retain 88% of their initial PCE after 1000 h damp hea t test and successfully pass the thermal cycling standard (IEC 61 215:2016) with 95% retention of initial PCE after 250 cycles.

Source

The poor stability hampers the commercialization of perovskite solar cells (PSCs). Many methods have recently been reported to enhance their stability, among which encapsulation is one of the most effective methods to improve the stability of PSCs. Herein, a summary of the factors influencing the stability of PSCs is provided and the commonly used encapsulation technologies and different types of encapsulation materials in detail are introduced. Then, the characterization technologies of encapsulation and stability tests of encapsulated PSCs are proposed. Finally, current issues and chances for encapsulating material development are considered.

Source

In the last two decades, the continuous ever growing demand for energy has determined a significant development in the production of photovoltaic (PV) modules. Anyway, a critical and very important issue in the module design process is the adoption of suitable encapsulant materials and technologies for cell embedding. Therefore, adopted encapsulants have a significant impact on modules efficiency, stability and reliability, and to ensure the unchanged performance of PV modules in time, the encapsulant materials must be selected properly. The selection of encapsulant materials must maintain a good balance between the encapsulant performance in time and costs, related to materials production and technologies for cells embedding. However, the encapsulants must ensure excellent isolation of active photovoltaic elements by the environment, preserving accurately the PV cells against humidity, oxygen and accidental causes that may compromise the PV modules function. This review provides an overview of different encapsulant materials, their main advantages and disadvantages in adoption for P... Read More

Source

The dampheat (DH) degradation of silicon heterojunction (SHJ) solar modules leads to severe power loss, necessitating superiorquality encapsulation materials. Herein, it is aimed to investigate the mechanical, thermal, and optical properties of ethylene vinyl acetate (EVA), polyolefin elastomer (POE), and thermoplastic polyolefin (TPO). TPO demonstrates the lowest water vapor transmission rate (WVTR) of only 3.14 g (m 2 day) 1 , which is approximately seven times lower than that of EVA. The Fourier transform infrared spectroscopy of EVA demonstrates a loss of the carbonyl group, revealing the formation of acetic acid under DH stress, which is not observed in POE and TPO. Both glass/back sheet and glass/glass (G/G) modules show a significant influence of encapsulant material on DH degradation. The maximum output power ( P max ) of the G/TPO/G singlecell module maintains 96.6% of its initial value after 1000 h DH stress. After sealing the edge, the G/G commercialsize modules encapsulated with lower WVTR encapsulants display excellent DH reliability, and P max degrades <4.8% af... Read More

Source

Photovoltaic (PV) modules during field exposure are subject to many durability and reliability issues, such as potential induced degradation (PID). The shunting type PID (PID-s) can significantly affect module performance. Most of the current studies on PID-s focus on understanding its mechanisms and mitigating its effects by modifying the glass, cell, or encapsulant component. Since the backsheet type influences the water vapor transmission rate, the conductivity of the encapsulant is significantly influenced by the backsheet type, and hence the level of voltage drop in the encapsulant layer during the PID stress test. The higher the conductivity of the encapsulant, the lower the voltage drop in the encapsulant and the worse the PID. Therefore, in the current work, the influence of four different backsheet types (PVF, PVDF, PA, ECTFE) and two different encapsulant types (EVA and POE) on PID is investigated. With multiple construction combinations of these materials, a set of 1-cell modules were fabricated and stressed for PID using an environmental chamber at 1000 V and 85 C/85 %R... Read More

Source

Since the renewable energy thrive, performances and lifetime of photovoltaic (PV) modules have been one of the big international concern. The mechanical bonding between the different components and the materials' choice can significantly improve both performances and lifetime of PV modules. The manufacturing process plays also a significant part in the modules lifetime [G. Oreski, B. Ottersbck, A. Omazic, Degradation Processes and Mechanisms of Encapsulants, in Durability and Reliability of Polymers and Other Materials in Photovoltaic Modules (Elsevier, 2019), pp. 135152]. This work deals with the controlled cooling part of the manufacturing process. The aim is to characterize its influence on an encapsulant properties, and its influences on modules degradation. This work is a part of improving both performances and lifetime of PV modules. First, the work focuses on describing the real temperature seen by a thermoplastic polyolefin encapsulant during the lamination process. A multi-chamber R&D laminator is used and studied in order to better know the industrial equipment. Resul... Read More

Source

Encapsulation of photovoltaic cells was carried out using a transparent glass fiber reinforced composite with enhanced chemical recyclability based on a matrix of an epoxy resin containing cleavable functional groups. The current-voltage curves showed a decrease of 6.3% on the short-circuit current (Isc) after encapsulation of the cell, lower than the one observed for the reference non-recyclable standard epoxy composite. Its performance stability under thermal cycling, ultraviolet (UV), and damp-heat exposure was evaluated and compared with the one of the reference standard epoxy. Both resins showed good stability performance under UV exposure and thermal cycling accelerated aging. Moreover, a power loss below the 5% allowed by the photovoltaic standard was observed for the recyclable resin after 1000 h of damp-heat exposure, even the pronounced loss of 4.7% in power remains a concern. Regarding the recyclability, the composite was dissolved in acetic acid dissolution and glass fiber fabrics were successfully recovered. A new module was manufactured with these fabrics, showing this ... Read More

Source

Abstract Potentialinduced degradation (PID) may be a serious concern in photovoltaic (PV) modules and plants, particularly when approaching high system voltages (1500+ V). Here, we investigate PID occurring in bifacial rearemitter silicon heterojunction (SHJ) solar cells encapsulated in a glass/glass (G/G) module configuration with ethylene vinyl acetate (EVA) as an encapsulant. PID testing was performed at 85C in 85% relative humidity (RH), and the solar cells were subjected to 1 kV and +1 kV for up to 800 h. SHJ cells were found to degrade when subjected to 1 kV, and to a lesser extent when left unbiased in damp heat (DH) conditions, while the application of +1 kV prevented degradation. Although prone to PID after extended test durations, the SHJ minimodules investigated in this study noticeably passed the industry standard (IEC 61215:2021) PID test of 96 h. The degradation was primarily characterized by losses in shortcircuit current (I SC ) at the front side, followed by fill factor (FF) and opencircuit voltage (V OC ). A crosssectional transmission electronic microscopy... Read More

Source

Metal halide perovskites have emerged as promising candidates for next-generation of photovoltaics, thanks to the excellent optoelectronic properties, low cost and facile fabrication. However, perovskite solar cells are still suffering from the poor stability, mainly, limited by the severe degradation after contact with water and oxygen. Hence, the encapsulation techniques are critical for the commercialization of perovskite solar cells for real-world applications. In this work, we systematically compared three encapsulation materials and fully evaluated the impact of encapsulation on the materials and device stability. We intentionally tested the encapsulated samples in accelerated aging conditions, such as immersing them in boiling water. These accelerated stressing can effectively distinguish the encapsulation quality in a short period. The resulted hero devices encapsulated with optimized techniques showed significantly improved stability, suggesting great potential for real applications.

Source

This study presents the results of severe accelerated tests carried out on four encapsulated amorphous silicon (a-Si) mini-modules. All the a-Si mini-modules were exposed to a 85 C and 85% relative humidity damp heat (DH) prolonged treatment for 5000 h representing five times the duration specified by the IEC 61215 standard for qualification tests. For two of the four mini-modules, the DH test was preceded by a severe UV preconditioning, by applying 30 times the dose of 15 kWh/m 2 at a temperature of 50 C as prescribed by the IEC 61215 standard, in order to enhance the degradation during the following DH test and to reduce the overall testing time. I V curves were plotted with a time step of 100 h under standard test conditions (STC) using a class A solar simulator and a source meter in order to monitor the degradation throughout both the tests. A visual inspection with photographic capturing was also performed at each stage to detect the apparent defects. Corrosion observed after 2000 h owing to the ingress of humidity is explained here by two possible infiltration paths in the ... Read More

Source

Commercialization of perovskite solar technology depends on reaching a stable functioning of the devices. In this regard, both intrinsic (chemistry phenomena of the different device layers) and extrinsic factors (environmental) need to be considered. In this chapter, we report the state of the art of encapsulation techniques against extrinsic degradation mechanisms. Our analysis includes the most common encapsulation structures, materials employed and their by-products, standard methods to test the stability of the devices (accelerated testing, outdoor and degradation monitoring), and security requirements to prevent the health/environmental hazard of lead leakage.

Source

Hermetic encapsulation is crucial for the lifespan of dye-sensitized solar cells (DSSCs). Sealing with glass frits provides hermetic encapsulation and extends the lifetime of DSSCs yet so far has been performed at inconveniently high temperatures, above 300 C, not compatible with most DSSCs materials. This study develops a new laser-assisted glass frit sealing process at low process temperature of 110 C. For the first time, glass frit encapsulation becomes fully compatible with most heat-sensitive materials used in DSSCs and did not affect the device performance after sealing. Hermeticity and durability of the seal complies with MIL-STD-883 and IEC61646 standards. Unique glass frit sealing configuration, parameters of the laser beam, and sealing protocol are disclosed. The developed glass frit sealing is fully compatible with liquid junctions DSSCs based on iodine and cobalt mediators and the resulting devices showed 1000 h of stability under simulated solar light according to ISOS-L-2 testing conditions. The new low-temperature sealing method allows a simplified DSSCs fabrication ... Read More

Source

A backsheet stack for photovoltaic modules that provides long-term moisture protection. The stack comprises an outer UV-resistant layer, an inner adhesive layer, at least one moisture barrier layer, and at least one reinforcement layer. The barrier layer prevents moisture penetration while the reinforcement layer provides mechanical stability. The stack's design enables equalization of moisture levels across the layers over time, preventing moisture-related damage.

Source

The performance of perovskite solar cells (PSCs) has seen rapid growth in the last decade due to the meticulous optimization of device fabrication procedures and material compositions. Most reports focus on device fabrication protocols in an inert atmosphere. Only a few offer reproducible methods to fabricate PSCs in ambient air, and even fewer report the stable maximum power point (MPP) operation of devices. This methods/protocol article presents detailed protocols for fabricating 20% milestone PSCs in ambient air and their encapsulation toward a stable 500+ h MPP operation. We also developed a simple encapsulation testing protocol: we found that if an encapsulated device withstands 120 C heat stress for 5 min in ambient air, it likely withstands long-term MPP conditions.

Source

A photovoltaic module with improved packaging technology for perovskite solar cells. The module includes a moisture treatment layer that absorbs moisture and converts into a solidified layer with enhanced cross-linking density, thereby preventing moisture ingress and extending the module's lifespan. The moisture treatment layer can be integrated into the module's packaging structure, including the base plate, cell string, and cover plate, and can be designed to detect moisture levels through response information.

Source

The most common encapsulant used in the photovoltaic (PV) modules is ethylene vinyl acetate (EVA). The properties of EVA can be tailored by modulating its vinyl acetate (VA) content. As a rule of thumb, EVA containing 28 to 33 % VA content is used as an encapsulant in PV industry. It is well known that the EVA films degrade due to the environmental stressors like humidity, temperature and solar radiation during the field operation of the modules. The immediate consequence of the EVA' degradation is the loss of its optical properties which ultimately reduce the electrical performance of the PV modules. In this work, we summarize the effect of damp-heat and ultraviolet ageing on the free-standing films of EVA that contain the VA content outside the most commonly used and accepted range. The VA contents discussed here include 18, 24, 33, and 40 wt. % with the necessary additives. These films have been cured at 150 C under vacuum and subsequently subjected to accelerated damp-heat (85 C and 85% RH) aging and UV aging at a wavelength of 340 nm for 1000 and 2000 h. Tensile strength, therma... Read More

Source