Since the very first solar cells by Bell Labs, the main aim of R&D in the industry has been to manufacture modules with lower cost/watt and higher efficiencies. Around 60 years ago, we started with meagre conversion efficiencies of 4-7%. Currently, the mono and polycrystalline offering from key market players (tier-1 companies like Jinko) can provide at least 17% efficiency with over 25 years linear performance warranty. As the technology behind these standards are unchanged, small alterations in manufacturing processes that can result into better real-world performance gives an edge over competition. Even though newer innovations like bifacial (with applications in BIPV) and thin film are picking up traction, it will be a few years before they are ready for mass adoption, leaving a gap in the market till then. This is where the half cell solar modules fit in.
Half Cell Solar
The common polycrystalline panels (cells made from multiple silicon crystals with less material wastage) were always a cost-effective option for residential customers and small-business owners. However, over the past 2-3 years, newer manufacturing processes have started making mono panels much more economical. These modules can offer efficiencies upto 22.5%. Now, what if these cells are cut in half? Yes, that is the simplest explanation of half-cells. In these type of panels. the solar cells are cut in half to reduces losses. So, an usual run-off-the-mill 60 cell mono panel becomes 120 half-cell.
The electrical losses is directly proportional to the square of the current flow. Therefore, if we cut a cell in half, it reduces the current by half and cuts down the losses by one-fourth. This increases the panel efficiency and output. The other advantage of these type of PV cells is the better shade tolerance due to the 6-cell strings per panel. For example, a 120 half cell solar panel is essentially two lots of 60 half cells with three strings in parallel. Thus, even of some shade cuts-off one of the strings, theoretically, the remaining strings will generate power.
How Half Cut Panels Fits In?
Large manufacturers like Risen already have these types of PV cells in their product catalogue. They also invest in R&D to further fine-tune these products to reduce production (soldering and cell integrity) defects. These type of new incremental innovations are important in the industry because panels still contribute to about 45% of the system cost. As a result, efforts to minimize cost per wattage and overall system efficiency are technologically laudable, and increases solar power penetration and accessibility. To conclude, we can say that even these minor innovations in renewable energy field are significant to further our cause of a sustainable energy ecosystem.