CIGS PV Modules Research Articles

Design and characterization of a continuous solar simulator for photovoltaic modules with automatic I-V curve acquisition system

This paper presents the development, characterization, and testing of a continuous large-area solar simulator for PV modules with an automatic I-V curve acquisition system and the results of a CIGS PV module over 25 h of light soaking. The simulator was developed to perform the IEC 61215 stabilization test and automatic characterization of PV modules during indoor testing. The equipment records the I-V curves of the PV module at programmed time intervals so that the change in the electrical characteristics of the PV modules can be tracked over time. The test plane has an area of 1.2 × 2 m and an irradiance of 800 W/m2. The simulator was installed in a container and consists of 16 metal halide lamps of 1 kW each. The simulator is characterized by temporal instability, spatial non-uniformity, and spectral mismatch, resulting in CCB classification. The I-V curves of the tested PV module were measured every 30 s, with 200 I-V points per curve. The power change of the tested module occurs mainly in the first 12 min and stabilizes after about 5 h under the conditions selected for the test. The developed device can save significant resources compared to commercial continuous solar simulators. The ability to automatically track changes in PV module electrical parameters during light-soaking tests is presented in detail and provides important information for future work related to the development and characterization of solar simulators of this type.

Efficiency Assessment of Five Types of Photovoltaic Modules Installed on a Fixed and on a Dual-Axis Solar-Tracked Platform

A solution to increase the electrical output of the photovoltaic systems relies on solar tracking mechanisms that increase the amount of received solar energy. The experimental results obtained during a monitoring period of one year are comparatively presented in the paper for five types of photovoltaic modules installed on a fixed platform (as reference) and on a dual-axis solar tracking platform in the Renewable Energy Systems and Recycling R&D Centre of the Transilvania University of Brasov, Romania. The influence of the solar-tracking mechanism and the meteorological conditions specific to the four seasons during the monitoring period on the output of the analysed photovoltaic technologies are discussed in the paper. The solar tracking increases by 28% the amount of the yearly received solar energy and by 29.6% the electrical energy output of the entire PV platform. The solar conversion efficiency of the tracked PV platform is slightly increased (14.34%) when compared with the fixed one (14.17%). When assessing the influence of solar tracking on each type of PV, the results show that the CIGS PV module has the highest relative energy gain (34%) followed by CIS (30.8%), m-Si (30.6%), p-Si (27.3%) and CdTe (23.4%) PV modules.

Extraction and microscopic analysis of partial shading‐induced defects in a commercial CIGS PV module

AbstractThe ever‐increasing instalment capacity of Cu (In, Ga)(Se, S)2‐based photovoltaics calls for a better understanding and control of their reliability. In this paper, we show how using a coring‐based method, small samples can be extracted from full size commercial modules, and prepared for lab‐scale analysis. The method is applied to a Cu (In, Ga)(Se, S)2 (CIGS) module where a non‐reversible, propagating (‘wormlike’) defect has been created in a controlled partial shading experiment. Through current–voltage, photoluminescence and illuminated lock‐in thermography analyses on an undamaged part of the module, the method used is shown to yield fully functional, undamaged active cells, with a photovoltaic conversion efficiency above the full module efficiency. Where the wormlike defects were present, a typical strong shunting behaviour is observed, as well as an increased sulphur content near the edge of the wormtrails. Furthermore, the wormlike defect propagation is shown to be strongly influenced by the present of specific features near the interconnects, which could be the result of manufacturing. These results demonstrate the potential of coring to analyse module failure with all the laboratory tools available. They also shed some light on how wormlike defects, which are a rare but serious hazard for CIGS modules reliability, can form and propagate in commercial, monolithically interconnected modules.

Degradation behaviors of EVA encapsulant and AZO films in Cu(In,Ga)Se2 photovoltaic modules under accelerated damp heat exposure

This paper focuses on the degradation behavior of ethylene vinyl acetate (EVA) and Al-doped ZnO (AZO) films in CIGS PV modules after the damp heat test. We observed losses of the FF and efficiency in the modules after 1000h of damp heat (DH) exposure and some of them were discolored from the outside edge and the center. To clarify the degradation behavior of the non-discolored and discolored modules, a failure analysis for each position of the EVA and AZO in the CIGS module films from the edge to the center was performed. The resistivity of the AZO films in the non-discolored modules increased due to the adsorption of oxygen. In discolored modules, the resistivity of the AZO films rapidly increased at the edge region, and the morphologies of the AZO films were also changed due to the chemical degradation of EVA. These degradation behaviors of the AZO films and EVA in discolored modules were attributed to the formation of hydroxyl and carboxylic species caused by water penetration. Moreover, we reported that the transmittance and the mechanical properties of EVA after 1000h DH exposure were deteriorated by water molecules.

Energy matrices analyses of hybrid photovoltaic thermal (HPVT) water collector with different PV technology

In this paper, an attempt has been made to evaluate and compare the energy matrices of a hybrid photovoltaic thermal (HPVT) water collector under constant collection temperature mode with five different types of PV modules namely c-Si, p-Si, a-Si (thin film), CdTe and CIGS. The analysis is based on overall thermal energy and exergy outputs from HPVT water collector. The temperature dependent electrical efficiency has also been calculated under composite climate of New Delhi, India.It is observed that c-Si PV module is best alternative for production of electrical power. Maximum annual overall thermal energy and exergy is obtained for c-Si PV module. The maximum and minimum EPBT of 1.01 and 0.66years on energy basis is obtained for c-Si and CIGS respectively, whereas on exergy basis maximum EPBT of 5.72years is obtained for a-Si and minimum of 3.44 in obtained for CIGS PV module. EPF and LCCE increase with increasing the life time of the system.

Effects of ZnO:Al films on CIGS PV modules degraded under accelerated damp heat

For the successful commercial production of CIGS PV modules, a good long-term damp heat stability of solar modules is necessary. The causes for the degradation of encapsulated solar modules are clearly explained. This article investigates the degradation behavior of encapsulated CIGS PV modules combined with the failure analysis of AZO films in CIGS cells. CIGS PV modules were exposed to the damp heat test of the IEC 61646 qualification standard—the modules are discolored from the outside edge to the center. Moreover, each module had its own distinct discolored area. The discolored area of the modules is significantly associated with the degradation of FF and efficiency. To clarify the causes of the degradation of FF and efficiency, failure analysis of AZO films in CIGS cells was performed. Electrical and structural properties as well as observation of the microstructure depending on the position of the AZO layers were characterized to explain the degradation mechanism of the encapsulated CIGS PV modules. It was revealed that the discoloration phenomenon of the modules and the degradation of AZO films were caused by the penetration of water molecules and adsorption of oxygen. By XPS and FT-IR analyses, the causes of degradation were confirmed. It was attributed to the generation of Zn(OH)2 and carboxylic acids by a combination of EVA, AZO and water molecules.

Thin-film CIGS PV modules with more than 3000 h damp heat stability: Breakthrough time property of the B-Dry® edge sealant and its characterization

Photovoltaic cells need to have a long operative lifetime, in order to be competitive against the so-called polluting sources. In particular, thin-film technologies such as CIGS suffer from degradation due to moisture ingress into the panel. An edge sealing tape applied in addition to a standard lamination foil used in the encapsulation process can strongly reduce the moisture permeation and degradation.

Scale-up issues of CIGS thin film PV modules

Photovoltaics cost has been declining following a 70% learning curve. Now the challenge is to bring down the cost of solar electricity to make it competitive with conventional sources within the next decade. In the long run, the module efficiencies tend to reach 80% of the champion cell efficiencies. Using a semiempirical methodology, it has been shown earlier that while the triple junction a-Si:H thin film technology is competitive, CIGS and CdTe thin film module technologies are highly competitive and presently offer the best approach for significantly exceeding the cost/performance levels of standard and non-standard crystalline Si PV technologies. Since 2006, the production of thin film solar cell in the U.S. has surpassed that of c-Si. At present, the production of CIGS PV modules lags considerably behind that of CdTe PV modules. This is mainly because of its complexity. Scale-up issues related to various CIGS preparation technologies such as co-evaporation, metallic precursor deposition by magnetron sputtering and non-vacuum techniques such as ink-jet printing, electroplating or doctor-blade technology followed by their selenization/sulfurization are discussed so as to assist the CIGS technology to attain its full potential. Besides the welcome announcements of large volume production, it is essential to achieve the production cost below $1/Wp in the near term and attain production speeds comparable to CdTe production speeds. Comparable production speeds are expected to be achieved within the next decade. This will enable reduction of CIGS module production costs to ∼65¢/Wp that would be comparable to the CdTe module projected production cost. Additionally CIGS will have a higher efficiency premium.

Analysis of performance and device parameters of CIGS PV modules deployed outdoors

Two 20 W copper indium gallium diselenide photovoltaic modules were subjected to a thorough indoor assessment procedure, followed by outdoor deployment at the Nelson Mandela Metropolitan University as part of an ongoing study. The initial indoor measurement of maximum power output ( P MAX) of one of the modules was considerably higher than the manufacturer's rating (E.E. van Dyk, C. Radue and A.R. Gxasheka, Thin Solid Films 515 (2007) 6196). The modules were deployed on a dual-axis solar tracker and current–voltage characteristics were obtained weekly. In addition to the normal PV parameters of short-circuit current, open-circuit voltage, P MAX, fill factor and efficiency, shunt and series resistances were also monitored. The performances of the two modules are compared and analyzed and the results presented in this paper.