Degradations of silicon photovoltaic modules: A literature review

http://oa.upm.es/10081/2/doi.10.1016.j.solener.2011.06.011.pdf

Early degradation of silicon PV modules and guaranty conditions

The risk of power loss in crystalline silicon based photovoltaic modules due to micro-cracks

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.

Faults and infrared thermographic diagnosis in operating c-Si photovoltaic modules: A review of research and future challenges

After a fast photovoltaic (PV) expansion in the past decade supported by many governments in Europe, in this postincentive era, one of the most significant open issues in the PV sector is to find appropriate inspection methods to evaluate real PV plant performance and failures. In this context, PV modules are surely the key components affecting the overall system performance; therefore, there is a main concern about the occurrence of any kind of failure in PV modules. This paper aims to propose a novel concept for monitoring PV plants by using light unmanned aerial vehicles (UAVs) or systems (UASs) during their operation and maintenance. The main objectives of this study are to explore and evaluate the use of different UAV technologies and to propose a reliable, cost-effective, and time-saving method for the inspection of PV plants. In this research, different UAVs were employed to inspect a PV array field. For this purpose, some thermal imaging cameras and a visual camera were chosen as monitoring tools to suitably scan PV modules. The first results show that the procedure of utilizing UAV was effective in the detection of different failures of PV modules. Moreover, such a process was much faster and cost effective than traditional methods.

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Light Unmanned Aerial Vehicles (UAVs) for Cooperative Inspection of PV Plants

The resonance ultrasonic vibrations (RUV) technique is adapted for non-destructive crack detection in full-size silicon wafers for solar cells. The RUV methodology relies on deviation of the frequency response curve of a wafer, ultrasonically stimulated via vacuum coupled piezoelectric transducer, with a periphery crack versus regular non-cracked wafers as detected by a periphery mounted acoustic probe. Crack detection is illustrated on a set of cast wafers. We performed vibration mode identification on square-shaped production-grade Si wafers and confirmed by finite element analyses. The modelling was accomplished for the different modes of the resonance vibrations of a wafer with a periphery crack to assess the sensitivity of the RUV method relative to crack length and crack location.

https://iopscience.iop.org/article/10.1088/0957-0233/18/3/038/pdf

Resonance ultrasonic vibrations for crack detection in photovoltaic silicon wafers

An experimental approach for fast crack detection and length determination in full-size solar-grade crystalline silicon wafers using a resonance ultrasonic vibrations (RUV) technique is presented. The RUV method is based on excitation of the longitudinal ultrasonic vibrations in full-size wafers. Using an external piezoelectric transducer combined with a high sensitivity ultrasonic probe and computer controlled data acquisition system, real-time frequency response analysis can be accomplished. On a set of identical crystalline Si wafers with artificially introduced periphery cracks, it was demonstrated that the crack results in a frequency shift in a selected RUV peak to a lower frequency and increases the resonance peak bandwidth. Both characteristics were found to increase with the length of the crack. The frequency shift and bandwidth increase serve as reliable indicators of the crack appearance in silicon wafers and are suitable for mechanical quality control and fast wafer inspection.

Crack detection and analyses using resonance ultrasonic vibrations in full-size crystalline silicon wafers

A resonance vibration approach is developed to measure residual stress non-destructively in full-size multicrystalline silicon wafers used in solar cell manufacturing. This method is based on excitation of longitudinal resonance ultrasonic vibrations in the material using an external piezoelectric transducer combined with high-sensitive ultrasonic probe and data acquisition of the frequency response to make the method suitable for in-line diagnostics during wafer and cell manufacturing. Theoretical and experimental analysis of the vibration mode in single-crystal and multicrystalline silicon wafers is used to provide a benchmark reference analysis and validation of the approach.

https://iopscience.iop.org/article/10.1088/0268-1242/21/3/007/pdf

Resonance ultrasonic vibration diagnostics of elastic stress in full-size silicon wafers

An experimental approach for fast crack detection and length determination in full-size solar-grade crystalline silicon (Si) wafers using a Resonance Ultrasonic Vibrations (RUV) technique is presented. The RUV method is based on excitation of the longitudinal resonance vibrations and their real-time frequency response analysis. On a set of identical cast Si wafers with introduced periphery cracks, it was demonstrated that the crack results in a downward frequency shift in a selected RUV peak, increasing the resonance peak band width and a reduction of the peak amplitude. The frequency shift and peak broadening were found to increase with the length of the crack. Finite Element Analyses modeling supports experimental RUV results and the mechanism of resonance variation.

Crack Detection and Analyses using Resonance Ultrasonic Vibrations in Crystalline Silicon Wafers

An experimental approach for fast crack detection and length determination in fullsize solar-grade crystalline silicon wafers using a Resonance Ultrasonic Vibrations (RUV) technique is presented. The RUV method is based on excitation of the longitudinal ultrasonic vibrations in full-size wafers. Using an external piezoelectric transducer combined with a high sensitivity ultrasonic probe and computer controlled data acquisition system, real-time frequency response analysis can be accomplished. On a set of identical crystalline Si wafers with artificially introduced periphery cracks, it was demonstrated that the crack results in a frequency shift in a selected RUV peak to a lower frequency and increases the resonance peak band width. Both characteristics were found to increase with the length of the crack. The frequency shift and bandwidth serve as reliable indicators of the crack appearance in silicon wafers and are suitable for mechanical quality control and fast wafer inspection.

O. Polupan

Papers

Resonance ultrasonic vibrations for crack detection in photovoltaic silicon wafers

Crack detection and analyses using resonance ultrasonic vibrations in full-size crystalline silicon wafers

Resonance ultrasonic vibration diagnostics of elastic stress in full-size silicon wafers

Crack Detection and Analyses using Resonance Ultrasonic Vibrations in Crystalline Silicon Wafers

Crack Detection and Analyses Using Resonance Ultrasonic Vibrations in Full-Size Crystalline Silicon Wafers