Scientists at the Fraunhofer Institute for Solar Energy Systems have developed a new multi-crystalline solar cell with rear side contacts. The technique used in the production of these solar cells is known as ‘Metal Wrap Through’ or MWT.
In an MWT technique there are three main stages, which partially shift the front side contacts over to the rear side, thus reducing the front side metallization almost by 50%. During the first stage a laser is used to drill holes into the cells. The through-connection of the cells is simultaneously achieved through the subsequent silkscreen printing process for the production of rear side contacts. After this a silk-screen printing paste is used to cover the holes, which completes the electrical connection to the front side. This isolation of the contacts reduces additional costs.
Though the technique utilizes some great engineering work, still it is only able to increase the efficiency of a solar cell by a mere 0.5%. The additional expense is most definitely worth it because the minimization of metallization on the front side enables us to obtain reduced shading and thus increased energy production, which further leads to an increase in efficiency.
We cannot state this research is a breakthrough in solar cell technology, but if we want to see solar cells in the future then researches should be made on techniques that can increase the efficiency of the cell by a more respectable margin.
