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Journal ArticleDOI

Detection and analysis of hot-spot formation in solar cells

01 Feb 2010-Solar Energy Materials and Solar Cells (North-Holland)-Vol. 94, Iss: 2, pp 106-113
TL;DR: In this paper, infrared thermography (IR) was used to map the surface temperature distribution of solar cells while in the reverse bias mode, and it was observed that some cells exhibited an inhomogeneity of the surface temperatures resulting in localized heating (hot-spot).
About: This article is published in Solar Energy Materials and Solar Cells.The article was published on 2010-02-01. It has received 181 citations till now. The article focuses on the topics: Solar cell.
Citations
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Journal ArticleDOI
TL;DR: The types and causes of PV systems (PVS) failures are presented, then different methods proposed in literature for FDD of PVS are reviewed and discussed; particularly faults occurring in PV arrays (PVA).
Abstract: Faults in any components (modules, connection lines, converters, inverters, etc.) of photovoltaic (PV) systems (stand-alone, grid-connected or hybrid PV systems) can seriously affect the efficiency, energy yield as well as the security and reliability of the entire PV plant, if not detected and corrected quickly. In addition, if some faults persist (e.g. arc fault, ground fault and line-to-line fault) they can lead to risk of fire. Fault detection and diagnosis (FDD) methods are indispensable for the system reliability, operation at high efficiency, and safety of the PV plant. In this paper, the types and causes of PV systems (PVS) failures are presented, then different methods proposed in literature for FDD of PVS are reviewed and discussed; particularly faults occurring in PV arrays (PVA). Special attention is paid to methods that can accurately detect, localise and classify possible faults occurring in a PVA. The advantages and limits of FDD methods in terms of feasibility, complexity, cost-effectiveness and generalisation capability for large-scale integration are highlighted. Based on the reviewed papers, challenges and recommendations for future research direction are also provided.

308 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a comprehensive effort to review and highlight recent advances, ongoing research and future prospects, as reported in the literature, on the classification of faults in crystalline silicon (c-Si) PV modules and advanced diagnosis in the field, by means of the increasingly popular method of infrared thermal (IRT) imaging.
Abstract: Photovoltaic (PV) solar energy recorded an exponential growth, in worldwide scale, over the last decade. Inevitably, mature PV markets are becoming highly competitive, boosting the need for research and development (R&D) on efficiency and reliability optimization, maintenance and fault diagnosis of key components, such as the PV modules. Indeed, a significant number of studies and technical papers have been published up today, based on an extensive feedback from both laboratory and real (field) investigations of faults and advanced diagnosis applications, especially for crystalline silicon (c-Si) PV modules. Undoubtedly, such experience is of particular interest for current PV plant operators, future investors, maintenance engineers and the R&D sector of PV industry. However, up today, such research, published in the form of reports, technical papers or even books, remains mostly dispersed and unclassified. This paper represents a comprehensive effort to review and highlight recent advances, ongoing research and future prospects, as reported in the literature, on the classification of faults in c-Si PV modules and advanced diagnosis in the field, by means of the increasingly popular method of infrared thermal (IRT) imaging. In particular, the first main part of this paper, reviews the characteristics of the most common fault types of operating PV modules, in terms of electrical and thermal response. Then, the second part gives a thorough review of recently published research, as well as the state-of-the-art, in the fields of IRT-based fault diagnosis and thermal image processing. On the basis of these two individual though supplementary review parts, an overview table is presented, followed by a discussion on the future prospects and challenges, towards the understanding and diagnosis of faults and their propagation in operating PV modules.

230 citations

Journal ArticleDOI
TL;DR: It is shown that a closed-loop link exists between aging and mismatching since aging (which is nonuniform by its nature) causes mismatching among cells, whereas mismatching, in turn, mainly due to its thermal effects, leads to non uniform aging.
Abstract: In this paper, the different aging mechanisms taking place in photovoltaic modules are discussed, and the cause–effect links, which exist among such mechanisms, are evidenced. It is also shown that a closed-loop link exists between aging and mismatching since aging (which is nonuniform by its nature) causes mismatching among cells, whereas mismatching, in turn, mainly due to its thermal effects, leads to nonuniform aging.

142 citations


Cites background from "Detection and analysis of hot-spot ..."

  • ...In [64] and [65], the direct correlation between areas containing high-impurity contaminants and hot spots in different samples of multicrystalline-Si (mc-Si) modules is studied....

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Journal ArticleDOI
TL;DR: In this article, the authors proposed the use of thermal image processing and the Canny edge detection operator as diagnostic tools for module-related faults that lead to hot-spot heating effects.
Abstract: Today, conventional condition monitoring of installed, operating photovoltaic (PV) modules is mainly based on electrical measurements and performance evaluation. However, such practices exhibit restricted fault-detection ability. This study proposes the use of standard thermal image processing and the Canny edge detection operator as diagnostic tools for module-related faults that lead to hot-spot heating effects. The intended techniques were applied on thermal images of defective PV modules, from several field infrared thermographic measurements conducted during this study. The whole approach provided promising results with the detection of hot-spot formations that were diagnosed to specific defective cells in each inspected module. These evolving hot spots lead to abnormally low performance of the PV modules, a fact that is also validated by the manufacturer's standard electrical tests.

139 citations

References
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Journal ArticleDOI
TL;DR: In this article, nine different types of shunt have been found in state-of-the-art mono and multicrystalline solar cells by lock-in thermography and identified by SEM investigation.
Abstract: Nine different types of shunt have been found in state-of-the-art mono- and multicrystalline solar cells by lock-in thermography and identified by SEM investigation (including EBIC), TEM and EDX. These shunts differ by the type of their I–V characteristics (linear or nonlinear) and by their physical origin. Six shunt types are process-induced, and three are caused by grown-in defects of the material. The most important process-induced shunts are residues of the emitter at the edge of the cells, cracks, recombination sites at the cell edge, Schottky-type shunts below grid lines, scratches, and aluminum particles at the surface. The material-induced shunts are strong recombination sites at grown-in defects (e.g., metal-decorated small-angle grain boundaries), grown-in macroscopic Si3N4 inclusions, and inversion layers caused by microscopic SiC precipitates on grain boundaries crossing the wafer. Copyright © 2004 John Wiley & Sons, Ltd.

274 citations

Proceedings ArticleDOI
31 Dec 1997
TL;DR: The selection of the worst case cell should be improved by measurement of the module current at the characteristic break point of the I-V characteristic, and the hot-spot test procedure of IEC 1215 should be generalised for all types of cell interconnection circuits.
Abstract: Solar cell manufacturers should provide information to module manufacturers about the operation of their cells under reverse biased conditions. The inhomogeneous behaviour of cells under reverse biased conditions needs further investigation. In particular, cell damage during manufacture should be evaluated. To guarantee resistance of the module design to thermal overload due to partial shading, the number of cells in a sub-string should be limited to 20. The hot-spot test procedure of IEC 1215 should be generalised for all types of cell interconnection circuits. The selection of the worst case cell should be improved by measurement of the module current at the characteristic break point of the I-V characteristic.

210 citations

Journal ArticleDOI
TL;DR: In this paper, the concentrations of transition-metal impurities in a photovoltaic-grade multicrystalline silicon ingot have been measured by neutron activation analysis, and the results show that the concentration of Fe, Co, and Cu are determined by segregation from the liquid-to-solid phase in the central regions of the ingot.
Abstract: The concentrations of transition-metal impurities in a photovoltaic-grade multicrystalline silicon ingot have been measured by neutron activation analysis. The results show that the concentrations of Fe, Co, and Cu are determined by segregation from the liquid-to-solid phase in the central regions of the ingot. This produces high concentrations near the top of the ingot, which subsequently diffuse back into the ingot during cooling. The extent of this back diffusion is shown to correlate to the diffusivity of the impurities. Near the bottom, the concentrations are higher again due to solid-state diffusion from the crucible after crystallization has occurred. Measurement of the interstitial Fe concentration along the ingot shows that the vast majority of the Fe is precipitated during ingot growth. Further analysis suggests that this precipitation occurs mostly through segregation to extrinsic defects at high temperature rather than through solubility-limit-driven precipitation during ingot cooling.

206 citations

Proceedings ArticleDOI
03 Oct 2000
TL;DR: In this paper, the authors use portable infrared imaging systems (cameras) to measure both absolute and relative temperature distributions on small and large components with a high degree of temperature and spatial resolution.
Abstract: Anomalous temperature distributions are often an indication of atypical behavior in a device under investigation. Portable infrared (IR) imaging systems (cameras) now provide a convenient method for measuring both absolute and relative temperature distributions on small and large components with a high degree of temperature and spatial resolution. This diagnostic tool can be applied during the development, production, monitoring, and repair of photovoltaic cells, modules, and systems. Planar objects with nearly uniform material composition are ideally suited for analysis using IR imaging. This paper illustrates investigations of localized shunting in cells, resistive solder bonds in field-aged modules, module bypass diode functionality, reverse-bias (hot spot) heating in modules, temperature distributions in flat-plate and concentrator modules, batteries during charging, and electronic component temperature in power processing equipment.

70 citations

Journal ArticleDOI
TL;DR: By employing a combination of analytical tools including lock-in thermography and synchrotron-based x-ray fluorescence microscopy, transition metals have been identified at shunting locations in two types of low-cost multicrystalline silicon (mc-Si) solar cell materials as discussed by the authors.
Abstract: By employing a combination of analytical tools including lock-in thermography and synchrotron-based x-ray fluorescence microscopy, transition metals have been identified at shunting locations in two types of low-cost multicrystalline silicon (mc-Si) solar cell materials: cast multicrystalline and ribbon growth on substrate (RGS) At a shunting location in the cast mc-Si cell, silver and titanium, both contact strip materials, have been identified at the shunting location, suggesting a process-induced error related to contact metallization At a shunting location in the RGS cell, a material-specific shunting mechanism is described, involving channels of inverse conductivity type, where copper and iron are found The possible roles of these metals in this shunting mechanism are discussed These results illustrate the wide range of physical mechanisms involved with shunting in solar cells

56 citations