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Within the NextTec project, a German consortium of equipment and metrology manufacturers as well as R&D institutes successfully developed the next generation of high-throughput processes and equipment for gigawatt-scale Si solar cell production. The project goal was the development of technical concepts (proof of concept) for the realization of an increase in throughput by a factor of 2 to 3 compared to currently used industrial production technology, ideally with an equivalent equipment footprint and only moderately increased equipment costs. Consequently, system throughputs of up 15,000-20,000 wafers per hour are addressed. Based on these values, a production capacity of approximately 1 GW per system and year can be achieved.

In this paper are presented the investigation results concerning microstructure as well as mechanical properties of the surface layer of cast aluminium-silicon-copper alloy after heat treatment alloyed and/ or remelted with SiC ceramic powder using High Power Diode Laser (HPDL). For investigation of the achieved structure following methods were used: light and scanning electron microscopy with EDS microanalysis as well as mechanical properties using Rockwell hardness tester were measured. By mind of scanning electron microscopy, using secondary electron detection was it possible to determine the distribution of ceramic SiC powder phase occurred in the alloy after laser treatment. After the laser surface treatment carried out on the previously heat treated aluminium alloys, in the structure are observed changes concerning the distribution and morphology of the alloy phases as well as the added ceramic powder, these features influence the hardness of the obtained layers. In the structure, there were discovered three zones: the remelting zone (RZ) the heat influence zone (HAZ) and transition zone, with different structure and properties. In this paper also the laser treatment conditions: the laser power and ceramic powder feed rate were investigated. The surface laser structure changes in a manner, that there zones are revealed in the form of. This carried out investigations make it possible to develop, interesting technology, which could be very attractive for different branches of industry.

This research project presents the investigation results of laser remelting and alloying especially the laser parameters and its influence on the structure and properties of the surface of the 32CrMoV12-28 and X38CrMoV5-3 hot work steels, using the high power diode laser (HPDL). As a result of the performed research structure changes were determined concerning the grain size and reinforcement ceramic particle distribution in the steel surface layer. The reason of this work was to determine the optimal laser treatment parameters, particularly the laser power applied to achieve good layer mechanical properties for protection of this hot work tool steel from losing their work stability and to make the tool surface more resistant to action in hard working conditions. For alloying the tantalum carbide TaC, niobium carbide NbC as well as titanium carbide TiC powders were used. For investigations of the alloyed samples hardness and microhardness measurements of the different remelting areas were performed. The remelted layers which were formed in the surface of investigated hot work steel were examined metallographically and analyzed using light and scanning electron microscope as well as the investigations concerning ear resistance of the produced surface layer were carried out

В работе рассматриваются вопросы контроля качества тубной упаковки. Для определения уровня качества упаковки, отпечатанной флексографским способом, применяется комплексный метод, который позволяет выделить наиболее значимые параметры, влияющие на качество печати. Основными единичными показателями являются: растискивание, неприводка, изменение общего контраста, отклонение по цветам. Для определения коэффициентов весомости единичных показателей используется экспертный метод, основанный на опросе работников полиграфических предприятий, которые являются профессионалами в области печати упаковки и этикетки флексографским способом. Комплексная оценка качества печати позволяет связать визуальную оценку, инструментальную оценку и физические показатели качества тубной упаковки., The article considers the issues of quality control of tube packing. For determination of the quality level of the packing, printed by flexographic printing a complex method is used. This method allows to identify the most significant parameters, which influence the printing quality. The basic unit parameters are: dot gain, misalignment of colors, changing the overall contrast, deviation by color. Expert method, based on the survey of employees of printing companies who are professionals in the field of packaging and label flexographic printing, is used for determination of the weighting coefficients of quality indicators. Complex evaluation of printing quality allows to connect visual evaluation, instrumental, and physical indicators of tube packing quality., У роботі розглядаються питання контролю якості упаковки туби. Для визначення рівня якості упаковки, віддрукованої флексографічним способом, застосовується комплексний метод, який дозволяє визначити найбільш значущі параметри, які впливають на якість друку. Основними одиничними показниками є: розтиск, неприведення, зміна загального контрасту, відхилення по кольорах. Для визначення коефіцієнтів ваговості одиничних показників використовується експертний метод, заснований на опитуванні працівників поліграфічних підприємств, які є професіоналами в області друку упаковки і етикетки флексографічним способом. Комплексна оцінка якості друку дозволяє об’єднати візуальну оцінку, інструментальну оцінку і фізичні показники якості упаковки туби.

The study examines the directions of expansion of the range of wafer snack products of high nutritional value by using fish & plant semifinished products. The study scientifically grounds the benefits of using the new fish & plant semifinished products in manufacturing waffle salty snack products. The data provided in the article prove that the use of the fish & plant semifinished products & herbal ingredients enable a range of the new wafer snack products «Fish krekis» with high content of proteins, organic calcium, fiber and vitamins, with improved consumer properties, as well as more efficient use of Ukrainian raw fish materials., В статье предложены направления по расширению существующего ассортимента вафельных снековых изделий повышенной питательной ценности путем использования рыборастительных полуфабрикатов и улучшающих растительных компонентов. Научно обоснованы преимущества нового подхода применения разработанных рыборастительных полуфабрикатов в производстве вафельных снековых соленых изделий, связанные с повышением их питательной ценности, содержанием полноценного белка, органического кальция, пищевых волокон и витаминов, более рациональным использованием отечественной рыбной сырьевой базы. Приведены результаты исследования химического состава и показателей качества ассортимента разработанных соленых вафельных изделий без начинки «Крекисов рыбных» с использованием рыборастительных полуфабрикатов и растительного сырья, подтверждающие высокие потребительские свойства изделий., У статті запропоновані напрями розширення існуючого асортименту вафельних снекових виробів підвищеної поживної цінності шляхом використання риборослинних напівфабрикатів та збагачувальних рослинних компонентів. Науково обґрунтовано переваги нового підходу застосування розроблених риборослинних напівфабрикатів у виробництві вафельних снекових солоних виробів, які пов’язані з підвищенням їх поживної цінності, вмісту повноцінного білку, органічного кальцію, харчових волокон та вітамінів, більш раціональним використанням вітчизняної рибної сировинної бази. Наведено результати дослідження хімічного складу та показників якості асортименту розроблених солоних вафельних виробів без начинки «Крекісів рибних» з використанням риборослинних напівфабрикатів та рослинної сировини, які підтверджують високі споживні властивості виробів.

The article considers the possibility of using the carrot puree and oil from pumpkin seeds in the preparation of pastry product. Production technology and regulatory documentation for pastry products were developed and nutritional value of products was investigated., В статье рассмотрена возможность использования морковного пюре и масла из семян тыквы в приготовлении мучных кондитерских изделий. Разработана технология производства мучных кондитерских изделий, изучена питательная ценность изделий и разработана нормативная документация на мучные кондитерские изделия., В статті розглянуто можливість використання морквяного пюре та олії з насіння гарбуза в приготуванні борошняних кондитерських виробів. Розроблено технологію виробництва борошняних кондитерських виробів, досліджено поживну цінність виробів та розроблена нормативна документація на борошняні кондитерські вироби.

The article presents experimental data on the study of fermentation of dietary fibers of different origin under the action of bifidobacteria and lactobacilli. Citrus and apple pectin, flax fiber and glucose were used as substrate. The dynamics of the process was determined by the dependence of the content of short-chain fatty acids (propionic, butyric, valeric) in the analyzed systems on time. Qualitative and quantitative composition of shot-chain fatty acids were determined by gas chromatography.It was found that the amount of metabolites (propionic, butyric and isovaleric acids) depends both on the type of the fermentable substrate, and the type of bacteria used for fermentation., В статье представлены экспериментальные данные по исследованию ферментативного распада пищевых волокон различного происхождения под действием бифидо- и лактобактерий. В качестве субстрата использовали цитрусовый и яблочный пектины, льняную клетчатку и глюкозу. Динамику процесса распада определяли по зависимости содержания короткоцепочечных жирных кислот (пропионовой, масляной, валериановой) в анализируемых системах от времени. Качественный и количественный состав анализируемых кислот определяли методом газовой хроматографии.Установлено, что количество образуемых при ферментации пищевых волокон метаболитов (пропионовой, масляной и изовалериановой кислот) зависит как от вида ферментируемого субстрата, так и от вида бактерий используемых для ферментации.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 951-954, In this paper, we present n-type rear junction (RJ) PERT (Passivated Emitter Rear Totally-diffused) solar cell with the process improvement of Laser Contact Opening (LCO) process and rear pattern opened by laser. In detail, effect of laser process parameter such as laser power and pulse duration was evaluated in terms of impact on the cell efficiency and opening shape. Also LCO pattern such as line, dash and dot was optimized to reduce rear electrode contact area to minimize the recombination characteristics of n-RJ-PERT cells. Through this, we achieved 21.77% efficiency, and 686 mV open-circuit voltage(in-house measured) of n-RJ-PERT solar cell with plated Ni/Ag front contacts, Al2O3 rear passivation, and screen-printed local Al emitter on 110μm-thickness 6-inch n-type Czochralski (Cz) single crystalline.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 943-945, In this work, the evaluation results on industrial p-type mc-Si PERC cells using spatial atomic layer deposition for aluminum oxide from SoLayTec are shown. By optimizing the process flow and integrating a postdeposition anneal into the SiNx capping process we achieve 0.15% higher cell efficiency compared to remote microwave plasma-enhanced chemical vapor deposition. Furthermore, it is shown that the improved passivation quality resulting in Voc gain remains constant during light and elevated temperature induced degradation measurements.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 946-950, In this paper, we report the results of an upgrade from an Al-BSF solar cell line to a PERC (passivated emitter and rear cell) solar cell line, based on p-type mono-crystalline silicon (mono c-Si) material. For the rear side Al2O3 passivation, an InPassion ALD system of SoLayTec was used. The PERC solar cell optimization has been done in three main steps: first we optimized the rear side SiNx capping layer, leading to a solar cell efficiency increase of +0.4%abs with respect to the mono c-Si Al-BSF solar cell baseline. Secondly, we optimized the rear side polishing depth from 1-2 μm to 3-4 μm, which results in a solar cell efficiency gain of +0.5%abs with respect to the standard Al-BSF solar cell baseline. For the third optimization, the emitter sheet resistance has been increased from (78±3) Ω/sq to (90±5) Ω/sq, resulting in a solar cell efficiency of (20.44±0.17)% and a gain of >+0.8%abs with respect to the Al-BSF baseline. After several repeat runs, where the number of PERC solar cells has been increased to >1000 wafers per run with >1.0%abs solar cell efficiency gain, >50000 PERC solar cells have been processed over two days with a stable solar cell efficiency of (20.5±0.3)% and best cell with efficiency of 21.1%. The reliability of the InPassion ALD system has been improved by decreasing the breakage rate from 0.19%abs to 0.05%abs. Finally, it has been proven that with the latest configuration of the system, the breakage rate can be reduced even more to ≤0.05%abs.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 363-366, In this paper, we report ENN’s results in R&D and mass production of high efficiency silicon heterojunction solar cells. Using large-size industrial equipment and mass production compatible processes, ENN has developed hybrid silicon technology (HST) and achieved 23.4% heterojunction solar cell efficiency. We have successfully developed a low-cost approach to mass production, i.e., converting existing Gen8.5 (5.7m2) thin film solar line to high efficiency HST fab by upgrading and modification of key equipment and line automation. We have achieved average cell efficiency of 21.6% in pilot production and demonstrated 317 Wp power output using standard 60-cell (156 mm) modules. ENN’s unique technology route to mass production of high efficiency heterojunction solar cells has comprehensive competition advantages such as low capital cost, high production capacity, proven equipment performance & reliability, and fast ramp-up, etc. This provides a viable path for more manufacturers to penetrate into this area, quickly commercialize low-cost heterojunction technology, and further increase its competitiveness.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 958-960, One common requirement for all frontside contacted cells is to utilize fine finger lines with good conductivity. An established technique already proven in mass production is Fine Line Double Printing, able to deliver finger widths of 40-45 μm and an Aspect Ratio of 0.5. In this paper an evolution of this approach is described, where: 1) busbars are printed separately from fingers and 2) fingers are printed twice with the same screen. This patented concept allows for increased printing consistency and a greatly simplified process in terms of screens and tool.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 961-965, Currently back contacts of Silicon HJT (Hetero Junction Technology) cells are sputtered or screen printed Ag-layers or structures. The present work aims to replace these cost-intensive manufacturing steps by electron beam evaporation of aluminum using axial beam guns. Al-layers of the necessary thickness have been evaporated with a dynamic deposition rate of up to 3000 nm.m/min while keeping the solar cell below 200°C to avoid any thermal damage of underlying layers and junctions. The deposited aluminum layers exhibit specific electrical resistance of 2.8.10-6 Ω.cm, specific electrical contact resistance of 10-3 Ω.cm2 and more than 92 % averaged reflection in the NIR. By exchanging only the metallization step in a standard HJT cell processing without further process-optimization lead to cell efficiencies of 20.6 %. It can be stated that the electron beam evaporation can meet the technical and economical demands of the HJT production process. The high deposition rate can ensure the rear-side metallization of a 100 MW production line in one single deposition equipment.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 374-377, Standard direct plasma (40 kHz) batch-type PECVD machines can be equipped with TMA (Trimethylaluminium) and N2O supply to enable aluminium oxide (AlOx) / silicon nitride (SiNx) passivation stacks in one deposition run. The present paper is the summary of our process development for PERC structures and the implementation at an industrial production line of PERC cells at Gintech. Very good results were achieved on multicrystalline (19.3% average) as well as monocrystalline cells (21% average). This paper starts with the description of the TMA supply system, TMA plasma chemistry and properties. Then the optimisation of deposition procedures with lifetime tests and cell runs is illustrated. The optimisation resulted in a low surface defect density Dit

32nd European Photovoltaic Solar Energy Conference and Exhibition; 935-939, Dry and maskless texturing process of mono-crystalline silicon wafers using CF4/O2 plasma in a reactive ion etching (RIE) system has been studied for silicon heterojunction solar cells application. The main RIE process parameters have been changed and optimized in order to obtain a surface texture suitable to reduce the reflection of the silicon surface. Depending on gaseous mixture composition and process pressure, the etching mechanism can be modified from isotropic to anisotropic giving different shapes and sizes of surface features. At this purpose, effects induced by different plasma etching conditions on wafer surface morphology were systematically analysed in order to optimize the scattering properties. We verified that some typical texture parameters such as average Haze and RMS are not able to well explain reflection reduction. Differently, some specific texture functions such as angular distribution of scattered light and inclination angle distribution of the textured surface proved to be very effective in defining the most appropriate geometric surface parameters suitable to obtain large reflection reduction. In particular, with the aim of obtaining a textured surface with the lowest average reflectance in the wavelength range of interest, we have related the geometric parameters of the morphological features with the angular distribution of the scattered light obtained by ARS technique. Consequently, in this study we showed that, if shape and size of the characteristic surface features were appropriately modified by changing RIE process parameters, ARS curves very close to Lambertian behaviour can be obtained for etched silicon surface giving the highest reflection reduction.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 929-934, A process control system was developed which continuously monitors the composition of acidic etching baths. The simple physical parameters, sound velocity, conductivity, and refractive index are verified for suitability to determine the concentrations of hydrofluoric acid, nitric acid, and hexafluorosilicic acid. In pre-tests the characteristics of the individual concentrations were observed with the measuring devices and the effect of the formation of nitrous gases on the physical measuring devices is observed. In contrast to the conductivity electrode, the sound velocity and refractive index sensors show highly reproducible results. The formation of nitrous gases has no significant effect on the physical measurement methods. The influence of different concentrations of a mixture on the physical parameters is determined building up a design of experiment. With aid of multiple linear regression model equations were created which describe the quantitative relationship between the concentration and the physical variables. The model equations which lead to a quantitative correlation between the concentration of the acids as a function of the parameters sound velocity, conductivity, refractive index and temperature are compared and finally validated. The model equation predicts the concentration of HF with a recovery rate of 96.40%, HNO3 with 96.38% and Si in H2SiF6 with 78.74%.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 479-486, Intermetallic compounds (IMC) in solder bonds are commonly considered critical for the reliability of interconnections. The microstructure and thermal aging characteristics of solder bonds of crystalline silicon solar cells are investigated, whereby two solders, Sn60Pb40 and a lead-free, low melting point alternative Sn41Bi57Ag2 are considered. Solder bonds of front side busbars are formed with a semi-automatic tool and cross sections are prepared, which are characterized with confocal laser microscopy, scanning electron microscopy and energy dispersive x-ray spectroscopy (EDX). The kinetic of IMC growth is modeled with a diffusion model, and the parameters are obtained with systematic thermal aging studies and the Arrhenius relationship. The model is capable of processing non-isothermal temperature profiles and is used to simulate IMC growth during PV module reliability tests like thermal cycling 600 (TC) and damp heat for 3000 h. Furthermore, the thicknesses of the IMCs are estimated for a PV module in an outdoor location. It is found that solder joints undergo strong ripening processes during thermal aging. In particular, Sn41Bi57Ag2 solder joints show faster IMC growth, grain coarsening and Sn-penetration into the busbar than Sn60Pb40 bonds. Sn-penetration is observed already in the as-soldered condition and EDX confirms the existence of significant amounts of diffused Sn around cavities in the busbar. Large portions of the busbar are consumed by the Ag3Sn IMC after 155 h at 130 °C and further aging of the Sn41Bi57Ag2 joint leads to Bi segregation and, in some cases, complete depletion of Sn from the solder matrix. The simulation of IMC growth shows a final IMC thickness after TC 600 of 1.2 μm and 1.5 μm; furthermore, a thickness after 3000 h at 85°C of 2.6 μm and 3.7 μm respectively for Ag3Sn in Sn60Pb40 and Ag3Sn in Sn41Bi57Ag2 bonds. The prognosis of IMC growth in a PV module in the outdoor location estimates an Ag3Sn thickness of 1.2 μm and 1.3 μm for Sn60Pb40 and Sn41Bi57Ag2 respectively due to the rare occurrence of temperatures above 60 °C.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 358-362, In this paper we present the first results obtained at CEA-INES for the integration of thin and ultra-thin silicon wafers in the current silicon heterojunction (SHJ) LabFab Pilot Line production flow. Impact of the cell thickness reduction on final device characteristics is first detailed. Then overall compatibility of such wafers with current production constraints and actual equipment’s configuration is analyzed, identifying main breakage and throughput issues. Finally, improvement paths are proposed to enhance both efficiencies and reliability on the overall cell fabrication flow demonstrating also the potential compatibility of current SHJ production line for wafers as thin as 80μm.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 955-957, A new and simple patterning technique has been developed to fabricate local back contacts (LBCs) of rear-surface-passivated Si solar cells. Randomly hole-patterned polystyrene (PS) films were fabricated on p-type Si wafers by spin-coating of PS films followed by soaking in an acetone (ACE) solution. The hole-patterned PS films were then served as wet-etch masks of SiO2/SiNx stacked passivation layers, and LBCs were formed by wet-etch process followed by screen-printing of Al paste. The hole area fraction on the PS film can be adjusted by change of ACE soaking time. Passivated emitter and rear cells (PERCs) have been demonstrated using this patterning process.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 980-982, In this work we present the latest results on large area interdigitated back contact (IBC) Zebra cells. Within the framework of the European FP7 HERCULES project, we demonstrated the transfer and scaling-up of our IBC ZEBRA cell process to the pilot line production and fabricate more than 1100 solar cells for the industrial feasibility of the processes and for modules demonstration. The solar cells were fabricated in several batches at the ISC-Konstanz R&D laboratory. The n-type Cz Si wafers were provided by the project partner NorSun AS, with additional commercial reference n-type Cz wafers added as process control. It was found that the efficiency results depend on wafers supplier, with median of 21.1 % for NorSun material and 21.4 % for the reference material. In order to maximize the efficiency of ZEBRA cells in a pilot line production we investigated the effect that silicon material quality and resistivity variation occurring along the entire n-type Cz ingot have on cell performance. In addition, we studied the stability of the process on different wafer thickness.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 474-478, The impact of the emitter diffusion and firing process on gettering and hydrogenation of multicrystalline silicon is investigated with the aid of photoluminescence imaging and further image processing. Whilst the use of high efficiency emitters is critical to improve surface passivation, multi-crystalline wafers using highefficiency emitters suffered from a significantly reduced lifetime in the impurity-affected zone. For such diffusions, a pre-gettering step was required to increase the lifetime in this region. A pre-gettering step was also beneficial for such regions when using a screen print emitter. However the pre-gettering process was detrimental to the lifetime of other regions of the material for both emitter diffusions. Heavily diffused wafers showed a strong response to hydrogen passivation, particularly for non-gettered wafers. However, certain grains and the impurity-affected zone were reduced in quality after firing, suggesting a poisoning of the silicon.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 372-373, The manufacturing of front junction n-type silicon solar cells developed at Motech is presented in this paper. The cell features a rear surface field formed by phosphorous implant and a fully diffused BBr3 front emitter with thermal oxide passivation. Low damage laser process conditions are demonstrated to from the metal contact open by visible wavelength laser system. In our study, the green 532nm nanosecond laser (ns-laser) is used to ablate the passivation layer on the front-side of the solar cells. Our process combines laser ablation for the patterning of the dielectrics on front-side with a front metallization based on Ni/Cu forward bias plating and sintered metal paste for the rear contacting electrode. The performance results show better cell’s efficiency in comparison to common double sides sintered metal paste electrodes. Large-area (238.9 cm2) silicon solar cells manufactured on 170 μm thick, 3Ω - type Cz wafers using this technology, reach confirmed efficiencies up to 21.31%; with Voc of 654 mV, a jsc=40.8 mA/cm2 and FF of 79.8 %.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 966-968, In this paper, using the industrial mass-production technology on commercially available 156 mm × 156 mm p-type Czochralski-grown crystalline mono silicon wafers, the best cell efficiencies more than 21% are demonstrated. We improved the solar cell devices by improving front side anti-reflection coating and back side process parameter which results in higher open circuit voltages and short circuit current. Besides, the mono PERC solar cell process pass the UL/ITRI potential induced degradation (PID) test which condition was indicated to be 85 degree Celsius and 85% RH in climatic chamber apply -1500 V for 300 hours.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 469-473, Solar cells made of boron-doped, oxygen-rich Czochralski-grown silicon (Cz-Si) wafers suffer from a degradation in conversion efficiency upon illumination. This effect, sometimes labeled “light-induced degradation” (LID), is caused by a defect center within the silicon bulk, often referred to as BO defect, which activates its recombination properties under illumination leading to a degradation of the carrier lifetime. However, the BO defect center can be permanently deactivated, i.e. the lifetime can be permanently recovered, under illumination at elevated temperature. Within this contribution, we focus on transferring our lab-type BO deactivation process, using a hotplate and a halogen lamp, into an ultrafast high-throughput process, applying an industrial-type belt-furnace especially designed for this very purpose by centrotherm photovoltaics AG. Using this industrial furnace, inline processing in a solar cell production line is feasible. Our investigation clearly shows that a permanent recovery of the lifetime with an industrial belt-furnace can be achieved. In addition, we prove this result also for a shorter lab-type version of the longer industrial belt-furnace. The lifetimes reached after processing can be comparable to the lifetimes obtained on the same Cz-Si materials after applying our lab-type approach. Excellent stability of the lifetime is verified for up to 1000 hours of illumination at room temperature.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 925-928, This study presents the use of a multivariate statistical approach known as Structural Equation Modelling (SEM) to help interpret the sources of variance in end-of-line performance data. Using only the measured relationships between the Jsc, Voc, FF and Rs, it is shown that through the use of a path model, it is possible to infer the variance associated with a change in the front screen printed grid. This calculation is shown to closely match the variance contribution estimated directly from the actual measured finger width of the front screen. These models are very powerful and can be run automatically to detect changes in the sources of variance in production over time, and to trigger action. Depending on the available data, these models can become detailed and complex, and they can also be used to determine the most valuable and cost effective metrology for running a stable production process.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 367-371, Passivated Emitter and Rear Contact (PERC) is gaining acceptance in solar cell manufacturing due to its potential for high efficiency for p-type wafers and easy integration into existing lines. For p-type mono solar cells, the cell efficiency gain arrives 0.6~1.0%, while for multi solar cell is 0.5~0.8%, which is very attractive to the industry. We report the batch cell efficiency of 19.0% for multi PERC, and 20.70% for mono PERC solar cells in pilot run. As for PERC mass production, the effective and reliable AlOx deposition tool is the most important issue we have to consider. Nowadays, ALD and inline PECVD AlOx tools are the only two choices in the market. Here we compare the passivation effect and cell efficiency of both tools, to find little difference, but the former seems a little bit better. High-deposition rate PECVD AlOx shows the advantage of higher throughput and uptime, which is more acceptable by customers. Boron-oxygen complex is the origin of the light induced degradation (LID) of the solar cells. LID is the cell efficiency bottleneck because of the bulk recombination even if the silicon surface is well passivated. In this paper, we report the LID regeneration evaluation test by thermal and light illumination. Cell level tests reveal the relative degradation is around 2.0% for mono-PERC and 1.1% for mc-PERC, by means of LID regeneration, which is acceptable. The combination of cell efficiency, AlOx tool choice and LID regeneration gives a direction to industrialization the PERC technology.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 972-975, Experimental results from the fabrication and electrical characterization of semi-transparent monocrystalline Si solar cells, with transparencies exceeding 10%, are presented. The semi-transparency is achieved by laser-cutting ellipses through industrially-manufactured mono-crystalline Si cells. The ellipses are designed to be distributed uniformly over the whole surface area of the highly efficient cells and form two-dimensional periodic lattices. Depending on their size they are either confined between successive grid lines or intersect them. Incident sunlight is transmitted through the ellipses. The large number of cutting elements results in a uniform distribution of the solar radiation transmitted. High efficiencies of 14.2% and 13.2% have already been achieved with 156x156 mm2 semi-transparent mono-crystalline Si solar cells consisting of 91 and 106 ellipses respectively. In our newly-designed semi-transparent Si cells presented in this paper, ellipses with considerably larger sizes are used. In these cells both transparencies and the corresponding efficiencies exceed 10%.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 969-971, Inline photoluminescence (PL) imaging has been applied to identify impurity-decorated dislocation clusters and grain boundaries in as-cut wafers. The ratio of impuritiy-decorated dislocation clusters area and grain boundaries area to the total area in wafer can be calculated separately by software. Ten wafers are selected from bottom and top region of a central block with a defect area ratio of 7.5% to fabricate solar cells respectively. The result shows that for the samples with main grain boundaries defect, there is a 0.11% absolute efficiency higher than that of samples with dislocation clusters defect. It can be concluded that grain boundaries contribute a relatively less negative effect on the performance of solar cells after the gettering process. Meanwhile, impurities prefer to interact with dislocation clusters in top area of ingot.

In this paper is presented the structure of the cast magnesium alloys as cast state and after heat treatment cooled with different cooling rate, depending on the cooling medium (furnace, water, air). For investigations samples in shape of 250x150x25 mm plates were used. The structure have been study in the light microscope, scanning electron microscope equipped with an electron back scattering facility. The effects of the addition of Al on the microstructure were also studied. In the analysed alloys a structure of α solid solution and fragile phase β(Mg17Al12) occurred mainly on grain borders as well as eutectic and phase with Mn, Fe and Si. Investigation are carried out for the reason of chemical composition influence and precipitation processes influence to the structure and mechanical properties of the magnesium cast alloys with different chemical composition in as cast alloys and after heat treatment.

The South African REIPPP program is a success. To continue this success a continuous attention for the details is necessary. Focussing on the PV programs and more on the PV modules, this detail is the formulation of the local content. With the current formulation of the local content and its increasing value in subsequent rounds, the local manufacturers will face an abrupt demand change that is extremely challenging to manage. A suggestion is given to add to the local content formula a sentence describing that a fraction (proposed is 40%) of the PV modules installed in South Africa have to be laminated in South Africa. This formulation will result in a gradually increased production capacity and a healthy and sustainable local PV module industry including the vast majority of the raw materials. A local manufacturing of the PV modules in South Africa will be guaranteed, which eliminates the intrinsically cost increasing assembly of PV modules. No increase of the electricity price (R/kWh) will be obtained and most exciting, the development of the local private South African PV market will be significantly accelerated. In this way the REIPPP program fulfils its aim as the enabler for the local South African PV industry., 1st Africa Photovoltaic Solar Energy Conference and Exhibition Proceedings, AfricaPVSEC 2014

1st Africa Photovoltaic Solar Energy Conference and Exhibition Proceedings, AfricaPVSEC 2014

In the case of continuous casting of metal ribbons with the melt-spinning process on the industrial scale, a larger quantity of melt could lead to a slow excessive warming of the chilling wheel, which would further lead to solidification of a ribbon at non-uniform conditions and increased wear of the wheel. The primary goal of our work was to determine to what extent the release of heat during the contact of the melt/ribbon on the circumferential surface of the chilling wheel affects its surface temperature rise, and inversely how much elevated temperature of the chill wheel surface effect on metal ribbon cooling rate and its solidification velocity. The influence of the contact resistance and chill wheel cooling mode on cooling and solidification rate over ribbon thickness is outlined.

The main intention of this paper is to show the advanced technology for production of the electrode for EDM that has a relatively complex geometry. Five axes CNC machining centre is used for production of an example ice scrapers since application of other type of machine requires a lot of auxiliary time and resources. Advanced manufacturing technology involves the application of various software tools and technologies, among them the tools and technology to automate the design, analysis, testing and manufacturing occupy a key position. The main outcomes are decrease of production time, better quality of surface and product geometry. Decrease of cutting time refers to decrease of number of used tools, preparation time is lower in comparison with conventional machines. Practical implications: The practical part included the design of electrode in the CAD system, SolidWorks 2010, production of NC program for the operating unit Haidenhain iTNC 530 in CAM system ESPRIT 2010, and finally making the electrode on five axis machine center DMG DMU 40 Monoblock. Presented technology for a five-axis machining centre, ensures a great advantages in the process preparation while reduced set-up time, reduced number of required accessories and devices, reduced number of special tools is needed. This knowledge can support the development and design of technological processes.

Purpose of this paper is investigation of fine machining efficiency of 34CrMo4 steel with roller burnishing tools. Application of roller burnishing process as a clean and environmentally friendly machining process which can replace other pollution processes is of great interests. It is important to evaluate the influence of material properties (primary hardness) for smoothing efficiency and achieving of lower roughness and higher work piece hardness. Methodology: Experimental tests of cutting outputs have been done on specimens prepared for final machining process to estimate the rate of roughness decrease, and diameter increase. Roughness measured data before and after roller burnishing process have been compared. Findings: It was found that surface roughness is significantly lower after roller burnishing. Roughness ratio (before/after process) and decrease factor was 4 what doesn’t satisfy expected results. Some roughness results after burnishing exceed upper limits. Research implications: Results and findings presented in this paper are qualitative and might be slightly different in other machining condition (e.g. higher hardness materials and higher roughness of row material). Practical implications: Smoothing process can be performed on standard machine tools without additional reconfiguration tasks. Process is very rapid. Process is very versatile for any workshop and can be conducted without coolant what is additional advantages for the environment and pollution free machining. Originality: Originality of the paper is in analysis of results and smoothing efficiency with Wilcoxon test.

24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 2185-2189, In this work we investigated local rear contact structures and compared these to the full area Al-BSF structure. Two processes for local contacts are presented: The laser fired contact (LFC) process and a screen printing process to create a local back surface field (SP-LBSF) structure. The rear side passivation is provided by a firing stable SiO2/SiNx-stack, using a thin dry thermal SiO2 and a PECVD SiNx. We analyzed several process schemes to implement the local rear side structure with a screen printed front side metallization. As a flat rear side is very important for a successful implementation of a solar cell process with dielectric layer passivation, we focused on these processes. Monocrystalline Cz-Si solar cells (cell size 125x125 mm²) with an LFC structure and up to 17.6% efficiency were processed. The fabricated LFC cells show an increased reflectivity at long wavelengths due to the evaporated aluminum on the rear side. Furthermore, the internal quantum efficiency of the LFC and the SP-LBSF solar cells in the long wavelength range is significantly higher than for solar cells with aluminum back surface field.

24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 845-856, CrystalClear was an EU co-financed Integrated Project aimed at developing technology for waferbased silicon solar modules at 1 € per watt-peak manufacturing costs and a strongly improved environmental profile. The project consortium has selected a number of technologies that potentially comply with these aims as well as research that serves as basis for further developments (beyond the project aims). These technologies have been demonstrated in the form of demonstrators, i.e. full-size modules featuring all innovations necessary to comply with the aims. The project has shown that wafer-based multicrystalline-silicon solar modules can be produced at 1 € per watt-peak at a world-record efficiency of 16% and an energy pay-back time of less than 2 years in Southern Europe.

Purpose of this paper is investigation of dynamic impacts on cutting edge during machining of locally hardened steel. Alteration of hardness on a single workpiece is a source of impact on tool which could lead to breakage of cutting tool and workpiece surface damage in turning. Influence of material properties (primary hardness) is important when workpiece is locally induction hardened and part of material is soft annealed. Methodology: Experimental tests of cutting outputs have been done on specimens after induction hardening to evaluate the rate of variation of cutting forces, surface roughness and chip formation because of hardness alteration. Measured data of main cutting force were analyzed in frequency and time domain. Findings: It was found that chip formation condition, chip thickness and chip shape depends on cutting forces alteration in transition areas in the range of 10 to 15%. Much higher alteration of force signal is recorded when machining is performed with low depth of cutting value as a result of backlash in system. Mean value of cutting force correlates with depth of cutting, and roughness correlates oppositely to the hardness. Research implications: Results and findings presented in this paper are qualitative and might be slightly different in other cutting condition (e.g. other heat treatable steels or other hardening techniques or other single cutting point processes). There is evident force value alteration in the transition (hard to soft state) zone. Practical implications: Surface roughness is a consequence of both cutting impacts and of tool/workpiece loading condition. Originality: Originality of the paper is in analysis of stability of turning of heat treatable steel influenced with alternate workpiece hardness. It was recorded edge loading shock when overcoming from hard to soft machining. It is recorded and analyzed self-exited vibration. A new type of chips: horseshoe-type was found.

24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 1767-1770, The latest results in the application of selective doping structures to inline diffused industrial phosphorus emitters are presented. It was found that the efficiency of the cell can be increased substantially by partially etching back the highly doped layers created during the emitter diffusion. An average gain in the open circuit voltage (Voc) of 19 mV and a rise of the short circuit current density (Jsc) of 1.2 mA/cm², resulting from a significant decrease of recombination losses at the front surface of the cell, was measured. Combined with better fill factors achieved by contacting emitters with lower sheet resistivity, an efficiency gain of 1.4%abs was realized. The best cells show 18.1 % efficiency. The processes used for the investigations were performed on equipment used in large scale industrial production. Furthermore, novel inkjet masking methods were applied and their potential for improving selective emitters was evaluated. Inkjet printing is warp-free, applies no mechanical stress on the wafer and enables a precise structuring of the etch mask with very little lateral tolerances. This increase in precision lowers the areal fraction of low-resistance contact areas, resulting in lower emitter saturation current densities and thus improving the performance of selective emitters produced by inline processes.