The present work mainly deals with the testing and modeling of a commercially-available copper indium diselenide (CIS) ST40 module from the former Siemens Solar Industries (SSI). For this purpose, a large quantity of current/voltage characteristics were measured in the Paul Scherrer Institute (PSI)’s photovoltaic test-facility under different cell temperatures, solar irradiation and air mass, AM, conditions. They were used to develop a semi-empirical efficiency model to correlate all measured data sets. The goal was to make available a model, allowing quick and accurate calculation of the performance of the CIS module under all relevant operating conditions.
For the undegraded state of the module, the efficiency model allowed us to deduce the efficiency at Standard Test Conditions, STC, and its temperature coefficient at STC, which were 11.58% and minus 0.050%/°C, respectively. The output of the undegraded module under STC was found to be 42.4 W, i.e., 6% higher than specified by the manufacturer (40 W). Furthermore, the efficiency does not decrease with increasing air mass. At a cell temperature of 25 °C and a relative air mass of 1.5, the module has a maximum in efficiency of 12.0% at an irradiance of about 650 W/m2. This indicates that the series-resistance losses become significant at higher irradiances. Hence, improving the transparent conducting oxide (TCO) electrode on the front side of the cells might lead to a higher output at high irradiances.
Identical testing and modeling were repeated after having exposed the module to real weather conditions for one year. We found that the STC efficiency was reduced by 9.0%, from 11.58 down to 10.54%. The temperature coefficient of the efficiency had changed from minus 0.050 %/°C to minus 0.039%/°C. These results indicate possible chemical changes in the semiconductor film. The output of the module at STC was reduced by 9.0% from 42.4 W down to 38.6 W.
Using meteorological data from a sunny site in the South of Jordan (Al Qauwairah) and the efficiency model presented here allows us to predict the yearly electricity yield of the CIS module in that area. Prior to degradation, the yield was found to be 362 kWh/m2 for the Sun-tracked module; and 265 kWh/m2 for the fix-installed module (South-oriented, at an inclination angle of 30°). After degradation the corresponding yields were found to be 334 and 241 kWh/m2; meaning losses of 8.4% and 9.5%, respectively. (Note: all units of energy, kWh, are referred to the active cell area.) Having available efficiency models for other module types, similar predictions of the yield can be made, facilitating the comparisons of the yearly yields of different module types at the same site. This in turn allows selecting the best module type for a particular site. 相似文献
Multinary Cu(In,Ga)(Se,S)2 absorbers (abrev. CIGSSe) are promising candidates for reducing the cost of photovoltaics well below the cost of crystalline silicon. Shell Solar has pioneered production of this new thin film technology and is now with the first generation at a volume of well over 1 MW/year. In a separate pilot line for second generation products we have further improved the performance of CIGSSE based solar modules. We developed a novel CIGSSE formation technique called stacked elemental layer rapid thermal processing (SEL-RTP). This process has recently been scaled up from initial laboratory sized mini-modules (10 × 10 cm2) to full sized power modules of 60 × 90 cm2. The present paper concentrates on in situ and ex situ characterization techniques that were developed to control and further improve large area CIGSSE processing. The crystalline thin film formation process has been analyzed with in situ thin film calorimetry and in situ X-ray diffraction (XRD). That work has added fundamental insights and accelerates the optimization process. The depth distribution of gallium and sulfur has been determined by secondary ion mass spectroscopy (SIMS) for different selenization and sulfurization processes. Appropriate profiles of these elements allow for a deliberate bandgap profiling within the Cu(In,Ga)(S,Se)2 absorber. In addition further quality control tools like X-ray fluorescence analysis and Raman spectroscopy for stoichiometry monitoring, photoluminescence lifetime mapping and thermographic imaging have been developed in order to improve large area uniformity and reproducibility.
Some first full sized modules from the new pilot line look very promising: Aperture area efficiencies of up to 13.1% for monolithic thin film circuits on 0.54 m2 and a module power of 65 W represent an international champion value for large are thin film solar modules. 相似文献
High-energy proton irradiation (380 keV and 1 MeV) on the electrical properties of CuInSe2 (CIS) thin films has been investigated. The samples were epitaxially grown on GaAs (0 0 1) substrates by Radio Frequency sputtering. As the proton fluence exceeded 1×1013 cm−2, the carrier concentration and mobility of the CIS thin films were decreased. The carrier removal rate with proton fluence was estimated to be about 1000 cm−1. The electrical properties of CIS thin films before and after irradiation were studied between 80 and 300 K. From the temperature dependence of the carrier concentration in CIS thin films, we found ND=9.5×1016 cm−3, NA=3.7×1016 cm−3 and ED=21 meV from the fitting to the experimental data on the basis of the charge balance equation. After irradiation, a defect level was created, and NT=1×1017 cm−3 for a fluence of 3×1013 cm−2, NT=5.7×1017 cm−3 for a fluence of 1×1014 cm−2 and ET=95 meV were also obtained from the same fitting. The new defect, which acted as an electron trap, was due to proton irradiation, and the defect density was increased with proton fluence. 相似文献
This work reveals the formation of electrodeposition (ED) of CuInSe2 (CIS) film on flexible substrate. Ternary compounds were co-deposited on Au coated plastic substrate from an aqueous acidic solution containing 1 mM CuCl2, 5 mM InCl3 and 1 mM SeO2 adjusted to pH=1.65. It was found that the film stoichiometry improves when the growth solution consisted of 1 M triethanolamine (TEA) and 0.1 M Na-citrate. The optimal ED-CIS film was obtained after annealing at 150°C for 1 h in a nitrogen (N2) atmosphere. Optical absorption study showed that the energy gap of the annealed material is 1.18 eV. Good and reliable quality ED-CIS film was grown in this research with the potential use in fabricating flexible solar cells. This was supported by various analytical techniques, including energy dispersive spectroscopy (EDS), X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), ultraviolet/visible spectroscopy, Fourier transform infrared spectrometer (FTIR) and photoelectrochemical (PEC) characterization. 相似文献
A newly developed Doppler coherence imaging spectroscopy(CIS) technique has been implemented in the HL-2 A tokamak for carbon impurity emissivity and flow measurement. In CIS diagnostics, the emissivity and flow profiles inside the plasma are measured by a camera from the line-integrated emissivity and line-averaged flow, respectively. A standard inference method, called tomographic inversion, is necessary. Such an inversion is relatively challenging due to the ill-conditioned nature. In this article, we report the recent application and comparison of two different tomography algorithms, Gaussian process tomography and Tikhonov tomography, on light intensity measured by CIS, including feasibility and benchmark studies.Finally, the tomographic results for real measurement data in HL-2A are presented. 相似文献
Some currently popular strategies in Cochlear implants (CIs) fail to encode the temporal fine structure cues, which are crucial for speech perception in noise or melody appreciation of CI patients. We propose an improved strategy based on the CIS (Continuous interleaved sampling) model by introducing partial lowfrequency temporal fine structure cues or Frequency modulation (FM) information into the slowly varying temporal envelops. A psychoacoustic experiment was conducted to validate the improved strategy by measuring the Mandarin vowel, tone, consonant and sentence recognitions on normal hearing listeners. Experimental data show that the introduction of frequency modulation information can improve the CI performance greatly, especially for vowel and tone perception. Firstly even at the most severe noise condition the vowel perception can get nearly half intelligibility, and the tone recognition scores increased over 20% at various noise conditions. Secondly under moderate noise conditions or in quiet the fine structure cues also contribute significantly to the consonant and sentence recognitions. Finally, the proposed strategy has its own application values because it does not introduce too many high-frequency components into the model, which can not be perceived by deaf patients. . 相似文献