Effects of polymer binder on rheological properties of silver pastes for screen printing front electrode films of solar cells

2015 ◽  
Vol 29 (10n11) ◽  
pp. 1540027 ◽  
Author(s):  
Jun Qin ◽  
Weijun Zhang ◽  
Zhuofeng Liu ◽  
Shuxin Bai
Keyword(s):  
Solar Cells ◽  
Rheological Properties ◽  
Screen Printing ◽  
Model Parameters ◽  
Silver Particles ◽  
Front Electrode ◽  
Strength Of Interaction ◽  
Fundamental Understanding ◽  
Surface Modified ◽  
Down Sweep

The purpose of the study is to characterize and improve the fundamental understanding of the effects of Ethyl Cellulose (EC) binder on the rheological properties of silver pastes for screen printing front electrode films of solar cells. Dispersions of silver particles (surface modified with oleic acid) in EC polymer solutions with and without thixotropic agent were prepared; and yield stress values were measured by setting shear stress to characterize the strength of interaction in pastes. Week flocculation network of silver particles is produced due to depletion of flocculation. EC polymer also has a significant interaction with thixotropic agent. Down-sweep flow curves of dispersions without thixotropic agent were measured and well fitted by Generalized Casson model. The model parameters p indicated that EC polymer with high molecular weight has a stronger shear-thinning ability. Steady-state flow, three interval thixotropy shear test (3ITT) and oscillatory measurements were conducted to study the effect of EC content on viscosity, structure rebuilding and viscoelastic properties of electrode pastes. Increasing EC polymer is not the best way to prevent the layer printed from laying down.

Effects of organic medium on rheological properties of silver pastes for crystalline silicon solar cells

Circuit World ◽  
2016 ◽  
Vol 42 (2) ◽  
pp. 77-83 ◽  
Author(s):  
Jun Qin ◽  
Shuxin Bai ◽  
Weijun Zhang ◽  
Zhuofeng Liu ◽  
Hailiang Wang
Keyword(s):  
Solar Cells ◽  
Rheological Properties ◽  
Screen Printing ◽  
Crystalline Silicon ◽  
Organic Medium ◽  
Silicon Solar Cells ◽  
Silver Particles ◽  
Content Type ◽  
Crystalline Silicon Solar Cells ◽  
Front Electrode

Purpose The purpose of this paper is to characterize and understand the effects of polymer binder, thixotropic agent, solvent and organic medium content on the rheological properties of silver pastes for screen printing front electrode films of solar cells. Design/methodology/approach Dispersions of silver particles (surface modified with oleic acid) in ethyl cellulose (EC) polymer solutions with and without thixotropic agent were prepared, and yield stress values were measured by setting shear stress to characterize the inter-particle interaction strength of pastes. Steady-state flow, three interval thixotropy shear test and oscillatory measurements were conducted to study the effect of EC polymer and thixotropic agent on viscosity, structure rebuilding and viscoelastic properties of electrode pastes. The effect of solvent was studied by investigating the steady viscosity of cellulose acetate butyrate (CAB) polymer solutions and Ag dispersions. Findings Weak flocculation network of silver particles was produced because of depletion flocculation. Besides the interaction between thixotropic agent micelles, EC polymer also has a significant interaction with thixotropic agent. Merely increasing EC polymer or thixotropic agent content is not the best way to prevent the layer printed from laying down. The effect of solvent on the viscosity of paste is mainly attributed to the difference of hydromechanics radius and configuration of CAB polymer in solvents. With the increase of organic medium content, the properties of electrode pastes were converted from rigidity to flexibility. Originality/value It is still a challenge to obtain high-quality front electrode films for crystalline silicon solar cells by screen printing, because of the difficulty in reducing shadowing losses while ensuring a low series resistance and high filling factor. The paste rheological properties are the key properties related to the paste’s passing ability through the meshes and resistance of paste spreading on the substrate. Organic medium as an important component of the paste is acknowledged to be used to tailor the paste’s rheological properties and have a great role in screen printing.

scholarly journals Application Of Artificial Neural Networks In Modeling Of Manufactured Front Metallization Contact Resistance For Silicon Solar Cells

2015 ◽  
Vol 60 (3) ◽  
pp. 1673-1678 ◽  
Author(s):  
M. Musztyfaga-Staszuk ◽  
R. Honysz
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Solar Cells ◽  
Contact Resistance ◽  
Screen Printing ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Silicon Solar Cells ◽  
Front Electrode ◽  
Artificial Neural

Abstract This paper presents the application of artificial neural networks for prediction contact resistance of front metallization for silicon solar cells. The influence of the obtained front electrode features on electrical properties of solar cells was estimated. The front electrode of photovoltaic cells was deposited using screen printing (SP) method and next to manufactured by two methods: convectional (1. co-fired in an infrared belt furnace) and unconventional (2. Selective Laser Sintering). Resistance of front electrodes solar cells was investigated using Transmission Line Model (TLM). Artificial neural networks were obtained with the use of Statistica Neural Network by Statsoft. Created artificial neural networks makes possible the easy modelling of contact resistance of manufactured front metallization and allows the better selection of production parameters. The following technological recommendations for the screen printing connected with co-firing and selective laser sintering technology such as optimal paste composition, morphology of the silicon substrate, co-firing temperature and the power and scanning speed of the laser beam to manufacture the front electrode of silicon solar cells were experimentally selected in order to obtain uniformly melted structure well adhered to substrate, of a small front electrode substrate joint resistance value. The prediction possibility of contact resistance of manufactured front metallization is valuable for manufacturers and constructors. It allows preserving the customers’ quality requirements and bringing also measurable financial advantages.

Influence of screen printing parameters on the front metallic electrodes geometry of solar cells

Circuit World ◽  
2014 ◽  
Vol 40 (1) ◽  
pp. 23-26 ◽  
Author(s):  
Kazimierz Drabczyk ◽  
Piotr Panek
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Cross Section ◽  
Screen Printing ◽  
Printing Process ◽  
Content Type ◽  
Front Electrode ◽  
Printing Parameters ◽  
Screen Printed ◽  
Metallic Electrodes

Purpose – The paper aims to present results of investigations carried out on the front electrode of the solar cell. The front-side electrode for solar cells based on crystalline material is obtained by the screen printing method. Screen printing has been the prevailing method of electrode deposition because of its low cost. One of the ways to improve the cell efficiency and reduce the production costs is a further refinement of the metal electrode screen printing process. Design/methodology/approach – The researches were focused on the modification of mechanical parameters of screen printing process to ensure the best possible cross-section of the front electrode geometry. The main printing process parameters were constant, however, the print speed was variable. The obtained fine line of front contact was characterized morphologically – the dimension and geometry of the front contact cross-section – by scanning electron microscopy technique. Findings – The thin paths of 100 μm in width were screen printed applying a new silver-paste made by Du Pont. The printing speed has significant effect on print quality in the way that the lower speed enhanced the printed results. Research limitations/implications – For newest pastes (e.g. PV17D) influence of screen printing parameters on the front metallic electrodes geometry of solar cell is not so significant. Presented screen printing process can still give good results, but the further optimization for the new paste must be performed to achieve better cross-section geometry. Originality/value – This paper confirms that one-step screen printing process can still give good results. The screen printed thin paths of 100 μm in width have good cross-section aspect ratio.

scholarly journals Cell/Module Integration Technology with Wire-Embedded EVA Sheet

2021 ◽  
Vol 11 (9) ◽  
pp. 4170
Author(s):  
Jeong Eun Park ◽  
Won Seok Choi ◽  
Donggun Lim
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Power ◽  
Short Circuit ◽  
Optical Loss ◽  
Manufacturing Cost ◽  
Power Module ◽  
Manufacturing Method ◽  
Front Electrode ◽  
The Wire

Silicon wafers are crucial for determining the price of solar cell modules. To reduce the manufacturing cost of photovoltaic devices, the thicknesses of wafers are reduced. However, the conventional module manufacturing method using the tabbing process has a disadvantage in that the cell is damaged because of the high temperature and pressure of the soldering process, which is complicated, thus increasing the process cost. Consequently, when the wafer is thinned, the breakage rate increases during the module process, resulting in a lower yield; further, the module performance decreases owing to cracks and thermal stress. To solve this problem, a module manufacturing method is proposed in which cells and wires are bonded through the lamination process. This method minimizes the thermal damage and mechanical stress applied to solar cells during the tabbing process, thereby manufacturing high-power modules. When adopting this method, the front electrode should be customized because it requires busbarless solar cells different from the existing busbar solar cells. Accordingly, the front electrode was designed using various simulation programs such as Griddler 2.5 and MathCAD, and the effect of the diameter and number of wires in contact with the front finger line of the solar cell on the module characteristics was analyzed. Consequently, the efficiency of the module manufactured with 12 wires and a wire diameter of 0.36 mm exhibited the highest efficiency at 20.28%. This is because even if the optical loss increases with the diameter of the wire, the series resistance considerably decreases rather than the loss of the short-circuit current, thereby improving the fill factor. The characteristics of the wire-embedded ethylene vinyl acetate (EVA) sheet module were confirmed to be better than those of the five busbar tabbing modules manufactured by the tabbing process; further, a high-power module that sufficiently compensated for the disadvantages of the tabbing module was manufactured.

Surface-Modified TiO2Photoelectrode for More Efficient Dye-Sensitized Solar Cells

2014 ◽  
Vol 602 (1) ◽  
pp. 111-117 ◽  
Author(s):  
Jong Tae Kim ◽  
Dongyoung Kim ◽  
Hwa-Min Kim ◽  
Chul Gyun Hwang ◽  
Younghwan Kwon ◽  
...  
Keyword(s):  
Solar Cells ◽  
Dye Sensitized Solar Cells ◽  
Dye Sensitized ◽  
Surface Modified ◽  
Sensitized Solar Cells

scholarly journals Comparative Effects of MMT Clay Modified with Two Different Cationic Surfactants on the Thermal and Rheological Properties of Polypropylene Nanocomposites

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Meshal Al-Samhan ◽  
Jacob Samuel ◽  
Fatema Al-Attar ◽  
Gils Abraham
Keyword(s):  
Rheological Properties ◽  
Relaxation Times ◽  
Sem Analysis ◽  
Differential Scanning Calorimetric ◽  
Thermally Stable ◽  
Weight Percentage ◽  
Modified Clay ◽  
Modified Polymer ◽  
Mmt Clay ◽  
Surface Modified

Polypropylene montmorillonite (MMT) nanocomposites were prepared by melt blending using two different organoclays modified with imidazolium and alkylammonium surfactants. The imidazolium and ammonium modified organoclays were characterized by the FTIR and SEM analysis. The effect of organic clay (MMT) on the physical properties of polypropylene was evaluated, thermal and rheological properties with different filler weight percentage. Differential scanning calorimetric results showed that imidazolium modified clay (IMMT) exhibits low melting temperature compared to the ammonium modified clay (AMMT). The crystallinity analysis showed that crystallization improved in all nanocomposites irrespective of surface modification; the thermogravimetric analysis showed that the imidazolium modified polymer composites are more thermally stable than conventional ammonium modified composites. The Transmission Electron Microscopy (TEM) analyses indicated that the PP-IMMT composites displayed exfoliated morphologies compared with the intercalated structure in PP-AMMT, and the rheological analysis at 180°C showed an enhancement in the viscoelastic properties as the clay concentration increases. The melt viscosity, crossover modulus, and relaxation times were comparable for both the surface modified composites with two different cations. The imidazolium based surfactant was found to be an effective organic modification for MMT to prepare thermally stable PP/MMT nanocomposites.

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