CuSun - Elektroplettering af kobberlederbaner på solceller

Silver is used in the silicon PV industry to metallize the solar cells, primarily on the front side but also on the backside in order to collect the photogenerated current and make contactable surfaces. The silver is the major part of a paste that is screen printed on the cells and subsequently fired to create contact via a glass frit process. The result is a porous conductive substance with relatively low conductivity - at least compared to silver. However despite reductions in the silver consumption per cell, owing to machinery and process improvements there will still be silver shortage as the PV industry is predicted to consume 20 % of the annual silver production in 2027, and until 2050 use 85-98% of the current silver reserves, with current production forecasts. Thus the industry needs a paradigm shift to replace silver.

Plating with copper is a potential candidate, providing self aligned, dense, highly conductive paths on the cell, however despite copper plating was commercialized via BP in the early 90ths, plating with copper faces significant challenges, such as adhesion to silicon, creation of recombination traps from copper diffusion, and long term stability of the interconnected modules with high voltage stress has not been proven.

Within this project a copper plating line, and process for modern silicon solar cells will be developed as well as the stability of the plating metal scheme will be proved - also supporting high efficiency concepts as Poly cells, HJT cells as well as (TOPcon) cells. In addition geometric limitations from screen printing will be removed, enabling a paradigm shift in front grid design, and this will take the ohmic and shading losses to a new level, with a significant reduction in metal use.

The plating lines will be sold via Elplatek to solar cell line and, apart from significant potential cost reductions, the plating lines are considered necessary to continue the large scale PV rollout. Cu costs around 1% of silver and therefore a 99% reduction in consumables for the metallization can be achieved and the product can therefore maintain a high purchase price, which is important for entering the market, where price reduction can then be driven by scaling.