Optics + Photonics for Sustainable Energy最新文献

{"title":"Investigation of some transparent metal oxides as damp heat protective coating for CIGS solar cells","authors":"F. Pern, F. Yan, K. Zaunbrecher, B. To, J. Perkins, R. Noufi","doi":"10.1117/12.930539","DOIUrl":"https://doi.org/10.1117/12.930539","url":null,"abstract":"We investigated the protective effectiveness of some transparent metal oxides (TMO) on CIGS solar cell coupons against damp heat (DH) exposure at 85°C and 85% relative humidity (RH). Sputter-deposited bilayer ZnO (BZO) with up to 0.5- μm Al-doped ZnO (AZO) layer and 0.2-μm bilayer InZnO were used as “inherent” part of device structure on CdS/CIGS/Mo/SLG. Sputter-deposited 0.2-μm ZnSnO and atomic layer deposited (ALD) 0.1-μm Al2O3 were used as overcoat on typical BZO/CdS/CIGS/Mo/SLG solar cells. The results were all negative — all TMO-coated CIGS cells exhibited substantial degradation in DH. Combining the optical photographs, PL and EL imaging, SEM surface micromorphology, coupled with XRD, I-V and QE measurements, the causes of the device degradations are attributed to hydrolytic corrosion, flaking, micro-cracking, and delamination induced by the DH moisture. Mechanical stress and decrease in crystallinity (grain size effect) could be additional degrading factors for thicker AZO grown on CdS/CIGS.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128733991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative study of single-junction and triple-junction a-Si:H PV modules in hot and humid climate","authors":"N. Dhere, A. Kaul, S. Pethe","doi":"10.1117/12.930382","DOIUrl":"https://doi.org/10.1117/12.930382","url":null,"abstract":"With efficiency of PV devices approaching theoretical numbers and cost of PV coming down, the most essential factor that would determine their large scale deployment is the reliability and durability of the PV modules and the balance of system components. The degradation mechanism and reliability issues in PV cells must be determined by the tests carried out on field-deployed modules. With this goal outdoor testing of PV modules was undertaken. The outdoor performance variation of commercially available single junction and triple junction a-Si:H PV module has been studied in the hot and humid climate of Florida. After the initial Staebler-Wronski degradation, the a-Si:H PV modules typically degrade during the winter time when the temperatures are low and recuperate due to the annealing that takes place during the summer time. Due to this seasonal variation, the monthly data was considered in the multiples of 12. Performance variation calculated from the monthly PTC power showed +1.89±0.58% and +2.49±0.6% for positive and negative array of single junction a-Si:H PV modules and +0.42±0.87% and + 0.56±0.89% for the positive and negative array of triple junction a-Si:H PV modules respectively. The annual energy yield was found to be 1300 kWh/kWp/year and 1425 kWh/kWp/year for the single junction and triple junction a-Si:H PV arrays respectively.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134525663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examination of a junction-box adhesion test for use in photovoltaic module qualification","authors":"David C. Miller, J. Wohlgemuth","doi":"10.1117/12.929793","DOIUrl":"https://doi.org/10.1117/12.929793","url":null,"abstract":"Engineering robust adhesion of the junction-box (j-box) is a hurdle typically encountered by photovoltaic (PV) module manufacturers during product development. There are historical incidences of adverse effects (e.g., fires) caused when the j-box/adhesive/module system has failed in the field. The addition of a weight to the j-box during the “damp heat” IEC qualification test is proposed to verify the basic robustness of its adhesion system. The details of the proposed test will be described, in addition to the preliminary results obtained using representative materials and components. The described discovery experiments examine moisture-cured silicone, foam tape, and hot-melt adhesives used in conjunction with PET or glass module “substrates.” To be able to interpret the results, a set of material-level characterizations was performed, including thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. PV j-boxes were adhered to a substrate, loaded with a prescribed weight, and then placed inside an environmental chamber (at 85°C, 85% relative humidity). Some systems did not remain attached through the discovery experiments. Observed failure modes include delamination (at the j-box/adhesive or adhesive/substrate interface) and phase change/creep. The results are discussed in the context of the application requirements, in addition to the plan for the formal experiment supporting the proposed modification to the qualification test.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128413178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Permeation impact on metallization degradation","authors":"C. Peike, S. Hoffmann, P. Hülsmann, K. Weiß, M. Koehl, P. Bentz","doi":"10.1117/12.929819","DOIUrl":"https://doi.org/10.1117/12.929819","url":null,"abstract":"The degradation of the inorganic components in a PV module is, besides polymer degradation, one of the most important aspects of PV module aging. Especially the corrosion of the cell metallization may lead to significant decreases in PV module performance. But in which way the metallization corrosion is affected by the permeation of atmospheric gases is not understood, yet. In order to investigate this permeation impact, laminates with a systematic variation of back-sheet and encapsulation materials as well as different laminate set-ups were made. Two different kinds of encapsulation (EVA and PVB) and four different back-sheet materials (TAPT, PA and two different TPT foils) were used. Standard cells with a two and three bus bar set-up were used. The laminates were subjected to damp-heat aging tests with a relative humidity of 80% at 80°C and 90°C, respectively. The degradation was investigated by means of electroluminescence imaging, Raman spectroscopy and microscopy. Special attention was paid to the spatial distribution of corrosion effects on the cell. Furthermore, the occurrence of a typical damp-heat induced damage, apparent as a shaded area in the electroluminescence images, should be investigated. A corrosion of the grid and the ribbons could be observed. EDX measurements revealed the grid corrosion to go along with the formation of needles of lead compounds from the silver paste.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"249 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114002719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Method for site characterization of anisotropic diffuse illumination of photovoltaic systems","authors":"J. Russo, Deming Zhang, S. Vorndran, M. Gordon, J. Castillo, A. Brooks, V. Lonij, A. Cronin, R. Kostuk","doi":"10.1117/12.929419","DOIUrl":"https://doi.org/10.1117/12.929419","url":null,"abstract":"In this paper a method to characterize the anisotropy of diffuse illumination incident on photovoltaic systems is presented. PV systems are designed based on standard conditions in which only consider direct and isotropic diffuse illumination. Anisotropic illumination can cause the PV system output to step outside of the design specifications. A baffled multi-detector sensor system is described having a discrete set of azimuthal and declination angle combinations in order to constantly sample the irradiance and the incidence angle of the diffuse illumination in all zenith directions. The sensor was deployed in the Tucson Electric Power Solar Test Yard alongside with commercially available PV systems that are independently monitored. Constant and transient sources of anisotropic diffuse illumination, such as surface reflection and cloud edge effects respectively, are measured and modeled with ray tracing software. Results of the method are described for characterizing diffuse illumination at the TEP Solar Test Yard. Understanding the anisotropic diffuse illumination can potentially allow to more accurately predict PV system or to optimize energy harvesting of systems with non-standard mounting conditions as well as building integrated photovoltaic applications.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"76 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123271661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Indoor vs. outdoor aging: polymer degradation in PV modules investigated by Raman spectroscopy","authors":"C. Peike, T. Kaltenbach, K. Weiß, M. Koehl","doi":"10.1117/12.929828","DOIUrl":"https://doi.org/10.1117/12.929828","url":null,"abstract":"Indoor and outdoor aging tests are common methods for PV module degradation investigation. But to what extend are accelerated indoor aging tests comparable to outdoor exposure tests? The impact of indoor and outdoor tests on the polymer degradation in full-size PV modules was investigated. Polymer aging within a PV module is one of the major factors influencing module performance in the course of its lifetime. Degradation phenomena like yellowing, delamination or changes in the elastic modulus of the encapsulation may lead to transmission losses, corrosion effects or cell cracks. Raman Spectroscopy has recently been reported by our group as a non-destructive, analytical method for encapsulation degradation analysis. The degradation of the encapsulation of indoor and outdoor aged crystalline silicon PV modules was examined by the means of Raman Spectroscopy with special attention to the spatial-dependency of the degradation. The investigated modules were subjected to several different accelerated aging procedures with a systematic variation of the climatic conditions temperature, humidity and UV. Identical modules were aged in different climates (arid, tropical, urban and alpine) for up to three years. The degradation of the encapsulant was observed, resulting in an increasing fluorescence background in the Raman spectra. A dependency of the aging process on the relative position to the edges of the cell was found. The aging conditions appeared to influence the spatial distribution of the fluorescence and therefore, the polymer degradation, markedly. Furthermore, correlations between accelerated aging tests and outdoor exposure tests could be found.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"26 11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124047571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stability of CIGS solar cells and component materials evaluated by a step-stress accelerated degradation test method","authors":"F. Pern, R. Noufi","doi":"10.1117/12.930541","DOIUrl":"https://doi.org/10.1117/12.930541","url":null,"abstract":"A step-stress accelerated degradation testing (SSADT) method was employed for the first time to evaluate the stability of CuInGaSe2 (CIGS) solar cells and device component materials in four Al-framed test structures encapsulated with an edge sealant and three kinds of backsheet or moisture barrier film for moisture ingress control. The SSADT exposure used a 15°C and then a 15% relative humidity (RH) increment step, beginning from 40°C/40%RH (T/RH = 40/40) to 85°C/70%RH (85/70) as of the moment. The voluminous data acquired and processed as of total DH = 3956 h with 85/70 = 704 h produced the following results. The best CIGS solar cells in sample Set-1 with a moisture-permeable TPT backsheet showed essentially identical I-V degradation trend regardless of the Al-doped ZnO (AZO) layer thickness ranging from standard 0.12 μm to 0.50 μm on the cells. No clear “stepwise” feature in the I-V parameter degradation curves corresponding to the SSADT T/RH/time profile was observed. Irregularity in I-V performance degradation pattern was observed with some cells showing early degradation at low T/RH < 55/55 and some showing large Voc, FF, and efficiency degradation due to increased series Rs (ohm-cm2) at T/RH ≥ 70/70. Results of (electrochemical) impedance spectroscopy (ECIS) analysis indicate degradation of the CIGS solar cells corresponded to increased series resistance Rs (ohm) and degraded parallel (minority carrier diffusion/recombination) resistance Rp, capacitance C, overall time constant Rp*C, and “capacitor quality” factor (CPE-P), which were related to the cells’ p-n junction properties. Heating at 85/70 appeared to benefit the CIGS solar cells as indicated by the largely recovered CPE-P factor. Device component materials, Mo on soda lime glass (Mo/SLG), bilayer ZnO (BZO), AlNi grid contact, and CdS/CIGS/Mo/SLG in test structures with TPT showed notable to significant degradation at T/RH ≥ 70/70. At T/RH = 85/70, substantial blistering of BZO layers on CIGS cell pieces was observed that was not seen on BZO/glass, and a CdS/CIGS sample displayed a small darkening and then flaking feature. Additionally, standard AlNi grid contact was less stable than thin Ni grid contact at T/RH ≥ 70/70. The edge sealant and moisture-blocking films were effective to block moisture ingress, as evidenced by the good stability of most CIGS solar cells and device components at T/RH = 85/70 for 704 h, and by preservation of the initial blue color on the RH indicator strips. The SSADT experiment is ongoing to be completed at T/RH = 85/85.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127807462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting the reliability of polyisobutylene seal for photovoltaic application","authors":"H. Liu, Jie Feng, E. Nicoli, L. López, K. Kauffmann, Kwanho Yang, N. Ramesh","doi":"10.1117/12.931240","DOIUrl":"https://doi.org/10.1117/12.931240","url":null,"abstract":"Polyisobutylene (PIB) or butyl rubber has been used widely in applications such as construction materials, adhesives and sealants, agricultural chemicals, medical devices, personal care products, and fuel additives. Due to the unique low gas permeability, flexibility, and excellent weathering resistance, PIB or PIB based materials are frequently employed in photovoltaic (PV) industry as sealant to protect the electrical assembly in the package as well as moisture sensitive PV cells from aggressive environments. Long term behavior of the PIB sealant within the operating temperature range of the PV devices thus becomes a critical factor to the reliability of the device. In this paper, an experimental study of the temperature dependent fatigue behavior of a PIB based joint is presented. A finite element model capturing the joint region geometry is developed and an approach to estimate lifetime is proposed.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126084178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Statistical analysis of 10+ years field exposed c-Si modules performance degradation","authors":"J. Kuitche, G. Tamizhmani, R. Pan","doi":"10.1117/12.930436","DOIUrl":"https://doi.org/10.1117/12.930436","url":null,"abstract":"In our previous study1, visual inspections and infra-red (IR) scanning were performed on about 2,000 modules that have been operating under the dry and hot Arizona climate for 10 - 17 years. Most of these modules were installed on 1-axis trackers and grid-connected; and some were installed on a fixed latitude tilt rack in a standalone system. The modules were inspected against a list of historically known field failure modes, but restricted to those that could be visually observed or through IR. An analysis of the data revealed both positive and negative correlations between the failure modes. Failure chains could be constructed from those correlations; such as (1) Discoloration of encapsulant – cell discoloration, and (2) Delamination – broken/chipped cells. This study focuses on modules installed on 2-axis trackers between 8 and 13 years. Statistical degradation analysis is performed on power output data collected throughout the exposure period. The electroluminescence imaging and a more thorough IR scanning are performed on limited (available) samples to complement the visual inspection data from the previous study. This paper also looks into the correlation between those inspection results and the performance degradation data. The objective of this paper is twofold: (1) to present a statistical analysis result of degradation data for field exposed crystalline silicon modules installed on 2-axis trackers between 8 and 13 years. The analysis should provide reliability prediction for up to 30 years of field operation. (2) To investigate the correlation between performance degradation and inspection data. Inspections include visual observations, IR scanning, and electroluminescence imaging.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122520463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of moisture content in photovoltaic panel encapsulants using spectroscopic optical coherence tomography: a feasibility study","authors":"Shabnam Rashtchi, P. D. Ruiz, R. Wildman, I. Ashcroft","doi":"10.1117/12.928959","DOIUrl":"https://doi.org/10.1117/12.928959","url":null,"abstract":"EVA, a copolymer of ethylene and vinyl acetate, is a common encapsulant material used in silicon-based PV modules. It contributes to the structural integrity of the modules, provides electrical insulation and also acts as an environmental barrier. However, water can diffuse through EVA into the modules, leading to swelling and chemical degradation, which can impact interfacial bonds, leading to delamination and allowing more ingress to occur that can eventually end up in accelerated corrosion and device failure. Fourier Transform infrared spectroscopy (FTIR) and gravimetric techniques have been used to quantify water concentration and the diffusion coefficient in free standing EVA films. However, these techniques cannot be applied to measure water content in PV modules deployed in the field, as the encapsulant is usually between a glass front sheet and a back sheet made of glass or multilayered films. In this paper we study the feasibility of combining FTIR and spectroscopic optical coherence tomography (SOCT) to measure water concentration of the EVA layer inside the modules. SOCT provides depth resolved spectral information and thus has the potential of measuring water absorption at different layers in the PV module. These depth-resolved measurements are necessary to inform predictive models developed to study the structural integrity, stability and durability of PV modules. The fundamental principle of the technique is explained, the optimum spectral ranges are identified and the feasibility of a SOCT system is discussed based on light source and detector characteristics. Other strategies are also considered.","PeriodicalId":140444,"journal":{"name":"Optics + Photonics for Sustainable Energy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127466416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}