New solar energy technology ready for mass production

The pioneering Metal Wrap Through (MWT) technology for solar cells and panels is on the eve of mass production. The technology is the key to further cost reductions in solar energy as a result of a simplified manufacturing process, combined with higher efficiency and output. This is the most important conclusion drawn by the world’s largest solar cell and module manufacturers, equipment manufacturers, materials suppliers and high-level research institutes at a workshop in Amsterdam organised by ECN.

Promising alternative

The fourth international MWT Workshop in November 2012 made it crystal clear: MWT technology opens the door wide to further cost reduction of solar energy thanks to simplification of the manufacturing process and a higher yield. Current solar panels are mainly produced with the H pattern cells and tabbing: cells are connected to each other by means of metal strips (tabbing) on the broad front-side contacts of the H pattern.  By changing the front-end contacts into back-end contacts (Metal Wrap Through) and linking the cells to each other by means of foil, ECN has enhanced the ECN module manufacturing technology significantly. The industry can now deploy the technology in the manufacturing process. The MWT technology has already been taken into production at Canadian Solar (based on tabbing instead of foil) and in pre-production at Tianwei (using the conductive back-contact foils). Materials suppliers of the foils have announced major price breakthroughs. Equipment suppliers such as the Dutch company Eurotron are ready and waiting for mass production to start.

Big leaps

Here are some of the other results of the workshop:

• Canadian Solar started manufacturing MWT cells and modules in 2011 and currently has a production capacity of 100 Megawatts. The company has been able to increase the efficiency of solar cells from 19.6 to 20.6 per cent.

• At Tianwei, a module production capacity of 150 Megawatt has been installed. The company perceives the main benefits of MWT to be a higher power yield, less breakage and a simple transfer from laboratory to industry.

• The Dutch company Eurotron has become a major player in the MWT industry. It presented equipment for module manufacturing using conductive foils and a new, more cost-effective production method for foils.

The workshop

The two-day MWT workshop in Amsterdam, which took place late November, was organised by ECN and is a joint initiative of ECN and Fraunhofer ISE. This year, the workshop was attended by over 170 participants from all over the world. The workshop was organised with the support of industrial sponsors from the solar energy sector and the EU project Sophia. The next MWT workshop in 2013 will be held in Freiburg, Germany. Undoubtedly, new major accomplishments will then be reported. Next to MWT technology, the workshop also offers sessions on other routes, such as the back-junction back-contact technologies.