ISE makes progress in »electroplating« for solar cell contacting

Fully automated roll-to-roll laser transfer and fire system at Fraunhofer ISE: The system was developed as part of the publicly funded project »C3PO«.

It is an old dream of the solar industry: to replace the expensive silver in the contact fingers with copper. When nickel and copper are applied directly by »electroplating«, the contact fingers can also be much thinner, which increases efficiency because the photovoltaic active surface of the cell is less shadowed. However, before the plating can be applied, an existing electrical protective layer must be opened by laser. The contact finger is then electrochemically grown on the contact openings created in this way, initially from nickel (as a diffusion barrier between the copper and silicon), then copper and finally silver. The Fraunhofer Institute for Solar Energy Systems ISE has now made progress in the joint project »C3PO« (»Cool Copper Contacts - Development of an industrial low-temperature technology for the production of 20 micrometer fine copper contacts for bifacial PERC, Hetero and TOPCon solar cells«): Together with industrial partners on a system from Pulsar Photonics GmbH, the »Laser Transfer and Firing (LTF)" process could be mapped fully automatically, as stated in a press release. In the LTF process, metal is first transferred from a metal-coated foil to a solar cell in the desired contact finger layout using a laser printing process. In the second process stage, the resulting metal structures are formed into contacts on the solar cell surface. The process is now to be systematically tested and optimized with a view to industrial implementation.

Related News