Process Development for a High-throughput Fine Line Metallization Approach Based on Dispensing Technology

AbstractIn order to enhance prosperous dispensing technology towards an industrial application, besides a continuous process development, especially throughput rate has to be increased. In this study, paste rheology of two different dispensing pastes was transferred to CFD-simulation (CFD: Computational Fluid Dynamics) to investigate different nozzle geometries and print head designs. In the following, a single nozzle dispensing setup was used to verify simulative values by comparing them with those obtained from experimental investigations. Consequently, the single nozzle process was scaled to a parallel application, where a homogeneous pressure and flow distribution within the print head turned out to be crucial to achieve a homogeneous mass flow at all nozzles. In various iteration steps, the influence of fabrication tolerances especially concerning the nozzle geometry was isolated and print head designs were optimized based on CFD towards maximum process stability. Based on these results, a novel 10 nozzle fine line dispensing unit was designed and fabricated. Finally, successful cell production with resulting finger widths of less than 35μm could be demonstrated using the novel prototype

Geblaese zum Trocknen von Flaechen

The invention relates to a device for the drying of surfaces, in particular the surfaces of cars in carwash machines, be which an air flow generated by a fan is guided through an opening of a nozzle stretching across the surface. In order to reduce power losses and noise emissions, the fan according to the invention is formed by several individual compressors (3) arranged in a row along the row of nozzles, the outlet openings of which directly join to form a common nozzle opening (7) by being connected to the common nozzle (6). The front nozzle part forming the nozzle opening can be made to swivel about an axis parallel to the nozzle opening

Investigating the impact of particle size on the performance and internal resistance of aqueous zinc ion batteries with a manganese sesquioxide cathode

Aqueous zinc ion batteries are considered to be one of the most promising battery types for stationary energy storage applications. Due to their aqueous electrolyte, they are inherently safe concerning flammability and environmentally friendly. In this work, the strong influence of the particle size of manganese sesquioxide on the performance of the battery is investigated. Ball milling was used to decrease the particle diameter. The resulting powders were used as active material for the cathodes, which were assembled in coin cells as full cells together with zinc foil anodes and aqueous electrolyte. It was shown that about one third of the original particle size can nearly triple the initial capacity when charged with constant current and constant end-of-charge voltage. Additionally, smaller particles were found to be responsible for the collapse of capacity at high current densities. By means of electrochemical impedance spectroscopy, it was shown that particle size also has a large impact on the internal resistance. Initially, the internal resistance of the cells with small particles was about half that of those with big particles, but became larger during cycling. This reveals accelerated aging processes when the reactive surface of the active material is increased by smaller particles

Duesenanordnung bei einer Einrichtung zum Trocknen von Fahrzeugen

Die Erfindung betrifft eine Duesenanordnung, bestehend aus einem einen mit Luft beaufschlagbaren Hohlraum bildenden Duesenkoerper (1) und einem an den Duesenkoerper (1) angeschlossenen Schlitzteil (3), die in einer Einrichtung zum Trocknen von Fahrzeugen relativ zu dem zu trocknenden Fahrzeug bewegbar ist. Die Steuerung der Duesenbewegung erfolgt in bekannter Weise durch Abtastung der Konturen des Fahrzeugs. Um die Gefahr von Beschaedigungen bei eventuellen Zusammenstoessen zwischen der Duesenanordnung und dem Fahrzeug bei ihrer Relativbewegung zu vermindern und die Steuerung der Duesenbewegung leichter und sicherer zu machen, sieht die Erfindung vor, dass der Duesenkoerper (1) mindestens teilweise aus einem flexiblen, luftundurchlaessigen Material gebildet ist. In Weiterbildung der Erfindung ist vorgesehen, dass der Hohlraum des Duesenkoerpers (1) eine konische Form aufweist, wobei der Querschnittsverlauf des Hohlraums und die Schlitzbreite (b) des Schlitzteils (3) derart bemessen sin d, dass die Stroemungsgeschwindigkeit der Luft im Hohlraum groesser als 0 ist und auf der ganzen Laenge des Schlitzteils (3) ein positives Druckprofil besteht. Hierdurch tritt die Luft in schraeger Richtung aus dem Schlitzteil aus

Einrichtung zum Steuern von Arbeitsgeraeten, insbesondere von Geblaesen, Buersten, Duesen oder dgl. in einer automatischen Fahrzeugwaschanlage

Die Erfindung betrifft eine Einrichtung zum Steuern von Arbeitsgeraeten in einer oder mehreren Arbeitsstationen, insbesondere von Geblaesen, Buersten, Duesen od.dgl. in einer automatischen Fahrzeugwaschanlage, die die Oberflaeche eines Fahrzeuges bearbeiten, wobei Fahrzeug und Arbeitsstation relativ zueinander bewegbar sind, mit einem die Konturen des Fahrzeuges beruehrungslos abtastenden, durch mehrere Strahlungsschranken gebildeten Abtastsystem, dessen Strahlungsempfaenger bei Unterbrechung der Strahlungsschranken durch das Fahrzeug Ausgangssignale liefern, die ueber eine Schaltungsanordnung den Antrieb zur Positionierung des Arbeitsgeraetes steuern. Um die Stoerungsanfaelligkeit des Abtastsystems gegenueber Staub und verspruehten Wasserteilchen zu vermindern und es dennoch gleichzeitig in mehreren, aufeinanderfolgenden Arbeitsstationen einsetzen zu koennen, sieht die Erfindung vor, dass das Abtastsystem (1, 2) in Form von mehreren, mindestens in einer Reihe uebereinander und quer zu r relativen Vorschubrichtung von Fahrzeug bzw. Arbeitsgeraet angeordneten und seriell eingeschalteten und abgefragten Strahlungsschranken (7) sich vor der ersten Arbeitsstation (15) befindet, dass mindestens ein Speicher (8) zur Aufnahme von durch die Abtastung gewonnenen, der Lage der einzelnen Punkte der Kontur entsprechenden Messwerten sowie Mittel zur synchron mit dem Vorschub des Fahrzeuges (3) zu den Arbeitsstationen (15, 20, 22, 24) erfolgenden Uebertragung der Messwerte an eine einen Positionierungsantri ..

Correlations between finger geometry and dispensing paste rheology

An optimum adjustment of printing medium and machine parameters is essential to establish dispensing as an alternative front side metallization process for silicon solar cells. In previous studies [1-3], paste rheology was found to have a major impact on resulting finger geometry and process stability. In order to find a good balance between printability and resulting contact geometry, different dispensing pastes were evaluated and dispensed on Cz–Si 156x156 mm² precursor material equipped with standard aluminium printed back surfaces and pre-printed front side busbars. In order to determine the optimum co-firing temperature, three completely screenprinted cell groups were processed in parallel serving as reference cells. Cell results were investigated concerning finger geometry and electrical parameters. With increasing paste elasticity, the finger width could be reduced down to 43 ?m. Furthermore, contact width indicating possible paste spreading on the wafer surface as well as finger necking turned out to be a crucial geometrical parameter of dispensed contact fingers. Once more, the enormous potential of dispensing as a front side metallization technique could be demonstrated

Plasma etching for industrial in-line processing of c-si solar cells: Presentation held at the 19th European Photovoltaic Solar Energy Conference

Thinner wafers and the reduction of breakage losses make it attractive for solar cell manufacturers to use in-line production systems. Closing the gap between diffusion and in-line silicon nitride deposition systems a plasma etching system has been designed suitable for a throughput of 1000 wafer/h with an automated transport system. Different plasma sources appropriate for etching large areas were tested and etch rates of around 13 µm/min for saw damage removal could be reached with sufficient homogeneity. For phosphorous glass (PSG) removal selectivities between PSG and silicon above 10 could be achieved with a CF4/C2H4 etch gas mixtures with sufficient PSG etch each rates of around 80 nm/min. Solar cells processed with the plasma PSG removal step show slightly decreased efficiencies attributed to the plasma induced damage to the emitter layer and the silicon bulk. Further process optimization is needed to reduce this damage