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Verfahren zur lichtinduzierten galvanischen Pulsabscheidung zur Verstaerkung von Metallkontakten von Solarzellen und Anordnung zur Durchfuehrung des Verfahrens

Light-induced pulsed electroplating to reinforce front metal contacts of solar cells, varies potential, irradiation and current density periodically
 
: Radtke, V.; Bartsch, J.; Hörteis, M.

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Frontpage ()

DE 102008053621 A: 20081029
DE 102008053621 A: 20081029
C25D0005
C25D0007
Deutsch
Patent, Elektronische Publikation
Fraunhofer ISE ()

Abstract
(A1) Die vorliegende Erfindung bezieht sich auf ein Licht-induziertes galvanisches Pulsabscheidungsverfahren zur galvanischen Verstaerkung eines Metallkontaktes einer Solarzelle (S), wobei die Solarzelle (S) und eine als Anode dienende Hilfselektrode (H) zumindest abschnittsweise in einem elektrolytischen Bad (6) angeordnet werden, zwischen dem ersten Metallkontakt (R) der Solarzelle und der Hilfselektrode eine Potentialdifferenz ?URH so angelegt wird, dass der erste Metallkontakt gegenueber der Hilfselektrode zumindest zeitweise auf einem negativen Potential liegt, die Solarzelle so mit Licht bestrahlt wird (5), dass mittels des photovoltaischen Effekts ein Strom in der Solarzelle induziert wird und der zweite Metallkontakt (V) der Solarzelle als Kathode dient, wobei die Potentialdifferenz ?URH zwischen dem ersten Metallkontakt (R) und der Hilfselektrode (H), die Potentialdifferenz ?URV zwischen dem ersten Metallkontakt (R) und dem zweiten Metallkontakt (V), die Potentialdifferenz ?UVH zwischen dem zweiten Metallkontakt (V) und der Hilfselektrode (H) und/oder die Lichteinstrahlung auf die Solarzelle gemaess einer vordefinierten Spannungs-Zeit-Charakteristik und/oder Lichtbestrahlungs-Zeit-Charakteristik zeitabhaengig variiert wird/werden und/oder dass dieser Variation entsprechende Stromdichteaenderungen erzeugt werden.

 

DE 102008053621 A1 UPAB: 20100511 NOVELTY - In an electroplating apparatus for the solar cells, one or more of the following are varied: potential difference between electrodes and contacts, irradiation of the solar cells and current density. The relevant potential differences are: Delta URH between the first metal contact (R) and the auxiliary electrode (H); Delta URV between the first metal contact (R) and the second contact (V) and Delta UVH between the second metal contact (V) and the auxiliary electrode (H). The applied variation accords with a pre-defined voltage/time characteristic and/or corresponding current density variation. DETAILED DESCRIPTION - The first metal contact (R) is part of the rear solar cell contact and/or a contact on its p-doped side. In addition or alternatively the second metal contact (V) is part of a front contact, an electrical contact on the side facing the light irradiation and/or a contact on the n-doped side. The voltage, current-density or light irradiation is periodic in time. It follows a pulse sequence. Several pulse sequences, including intervals with no variation, are applied. A triangular-, square- or sine waveform is used. Second-, third- or higher degree polynomial waveforms are used. The waveform is exponential. Potential difference variations are produced by appropriately-connected function generator(s) which vary the relevant potential differences between contacts and electrodes. Irradiation of the solar cells is varied over time by a source connected to a frequency generator varying the voltage supplied. As an alternative the cell may be exposed to continuous light, which is interrupted by a mechanical chopper operating periodically. Delta URH is varied in accordance with the predetermined characteristic. In one variant method, Delta URV, Delta UVH, and/or the corresponding current density are not varied. Further details of applied voltage time variations between electrodes are described, in accordance with the foregoing principles. AN INDEPENDENT CLAIM IS INCLUDED FOR corresponding apparatus. USE - Light-induced pulsed electroplating used to reinforce front metal contacts of solar cells. The method is used especially in the manufacture of thin-layer solar cells (claimed). ADVANTAGE - The conductivity of the contacts is increased, so increasing the efficiency of the solar cells. The process is carried out by simple means and produces reliable results. Adhesion of the metal contacts is optimized. Internal stressing of the contacts is reduced. This also allows contacts to be manufactured with an improved aspect ratio. Dissolution of the rear contact is prevented. Production line manufacture of solar cells is cited.

: http://publica.fraunhofer.de/dokumente/N-139588.html