The company, a member of the Meyer Burger Technology Ltd group, says the new coating process, the HELiA system, uses inexpensive nickel in busbar metallization on both the front and rear sides of the solar cell. It is said to be available now.
In addition to nickel being a readily available material, Roth & Rau says the production costs of solar cells have been "significantly" reduced, since depending on the contact technology, between 50 and 70% in silver savings can be made.
In a statement released, it explains that the HELiA system uses a sputtering process to coat the solar cells with nickel in a shortened system configuration to form the busbars. The system is also said to permit simultaneous processing of both the front and rear solar cell surfaces.
Another feature of the new process, which has been primarily designed for the production of high efficiency heterojunction cells, is the "outstanding" adhesion of the cell connectors in the standard soldering process.
"The metallisation of the fingers can thus take place regardless of the electrical characteristics of the busbar and be optimised to match them. In this way, the metallisation of the fingers is de-coupled from the solderability of the busbar, thereby enabling the use of new pastes and metallisation processes that do not currently achieve reliable solderability. The performance of solar cells coated with this process is comparable with that of solar cells metallised in the conventional way by screen printing," continues the statement.
While no further information was made immediately available, pv magazine has contacted Roth & Rau for more specific details.