Ecoprogetti Srl has developed a new combined tabber and stringer (CTS) tool called ETS1800, which is wrapped with several advanced features. The Italian production equipment maker has put major emphasis on interconnecting high efficiency cell concepts, such as heterojunction, bifacial, PERC, on top of standard mono and multicrystalline cells. Other important improvements of the model are a higher throughput, less breakage, higher uptime and simple design.
The CTS can process solar cells with side lengths of 156 mm and 156.75 mm and thickness down to 160 µm. ETS1800 is designed to interconnect the cells with 4 and 5 busbars in standard configuration, while a possibility to process 3-busbar cells is optional. The cells are loaded into the machine by means of basket, which is loaded and unloaded automatically with a motorized belt.
A vision system inspects the cells for microcracks before sending them processing. The cell alignment is done mechanical as well as optically with a camera. The tool accepts ribbon sizes from 1.1 mm to 2 mm, which are stretched and fluxed by dipping before placed for soldering with a position accuracy of +/- 0.1 mm.
Regarding the core soldering process, the ETS1800 relies on a hybrid approach combining hot air with contact soldering in order to avoid thermal stress, which results in a high soldering quality with 2 N in peel test done with 1.5 mm ribbon. The cells are also heated pre- and post soldering, which again is done to avoid thermal stress. All this helps in keeping the breakage rate at less than 0.2%.
The ETS1800 offers the flexibility to adjust the soldering length as well as tab length. The distance between the cells in a string can be varied between 2 and 5 mm, the number of cells per string can be set between 1 to 12.
The entire process runs in two parallel lanes, finally attaining a throughput of 1,800 cells per hour. According to Ecoprogetti, the system is designed to be compact with a footprint of 3.4 m x 1.3 m and a special care has been taken to reduce the maintenance. The tool has a rated technical availability of 95%. The ETS1800 comes with remote access and online trouble shooting function.