Published on November 23, 2018
Not since they split the atom way back in 1917 has technology seen an advancement like this… Well it might be true for those in the solar industry and especially for Trina, but that’s still a little far-fetched for most. New advancements in panels are always occurring, power classes are constantly creeping up, perc technology, buzz bars, quantum thingy’s and wafers are all getting bigger and better while panels sizes stay the same. So what the big deal with this new craze?
Let’s call it half-cut technology instead of split cells. Mostly because it gives me an immature smile to think of panels on a roof being half-cut. This really is as simple as having 120 cells in the space that 60 cells would normally take up. The half-cut technology uses the exact same wafers as a normal panel but gives a better output in comparison to conventional panels because the half-cells produce half the current. Make sense so far? Power loss due to resistance within the panel is equal to the product of the square of the current and the resistance, halving the current reduces the losses due to resistance. Basically ‘half-cells produces half the current’ and ‘halving the current reduces the losses’
It’s not a huge difference in gains. All up, it can increase the output of a panel by up to 3% over what it would be with full-size cells. That’s about an 18% efficiency now being 18.5%. Making a 300-watt panel to 309 watts.
But it’s not just all about reducing losses. They have a better shading tolerance as well. The panel has two sides of strings of half-cut cells and the total output of the panel is from a parallel connection of the two sides, this is why the current in the datasheet for half-cut panels are not actually half of a conventional panel and why the junction box of the panel is at the centre rather than the edge of the panel. Having this setup brings in if one half of the panel experiences shading, it will affect the cells on the same side but not the cells on the other side of the panel. So what does this mean? A string of cells shut down when one cell is shaded, so a small spot of shade on a panel, caused by a low flying bird (poop), or fallen leaves, will knock one entire cell string out of action, but not affect the others. Because the half-cut panel has more strings and smaller cells, the effect of partial shade is less severe.
Overall, getting half-cut is a lot better for productivity and actually causes fewer losses.