Photovoltaic panel consists of many solar cells, which can be considered as semiconductor diodes with wide and extremely flat surface area for light to pass through. When projecting light to the photovoltaic battery, photons of light can stimulate electrons that are linked with atom to bounce off atom, and at the same time, holes appear in atom due to electron shortage, which is called “photon coming to create electron – hole pair”. If this pair is created near p – n junction, the contact voltage will push the electron to one side (N-type semiconductor’s) and the hole to one side (P-type semiconductor’s). As a result, if we connect two electrodes into two semiconductors, we can measure a voltage. The value of this voltage depends on the nature of the semiconductor substance and the impurities that are absorbed. This is also the photoelectric effect used mainly in the photovoltaic (PV) technology combined with semiconductor physics. Currently, manufacturers are constantly researching and manufacturing PV technologies to reduce losses, improve PV’s performance. In this article, we analyze the choice of PERC technology, Shingled, Silk 12BUSBAR for solar power projects.
PERC technology is very common nowadays, help increase conversion efficiency of PV dramatically.
The PERC PV cell has a passive layer made of P-type semiconductors, enables itself to absorb reflected ray of light at the back. The passive layer also help reduce the recombination of electrons and holes in the PV in order to increase the performance of semiconductor layer. At the same time, this passive layer with special structure reduces heat absorption of PV, resulting in reducing operating temperature and increasing working efficiency.
- Shingled is mono PV technology without busbar on the surface of the panel and the cells will be shredded and then reconnected together by busbar below the surface of the cell.
- To create a series of interconnected cells, a special link will be set up, connecting the busbar at the rear of this cell with the busbar at the front of the next cell. This cell will hang up the the cell behind, and the part covered by the cell in front, at the same time, also cover the remaining link between the two busbars.
With traditional PV panels, the busbars located on the surface of the cell cause obscuration to several parts of cell, make them unable to absorb sunlight, resulting in losses in the process of absorption and conversion of PV. Shingled managed to overcome that problem by hanging up several cells to cover the busbars, so that:
- No cell obscuration caused by busbar link;
- Reduce the distance between cells and increase surface area of cells;
- Reduce losses between busbar link;
The structure is divided into various cell ranges (up to 408 cells – more cells than other technologies) and the output current is normally higher than other technologies.
- SILK 12BUSBAR
In PV, the Busbars are responsible for “leading” electrons to move between cell rows and the more busbars, the higher PV’s performance gets. However, the increase of busbars results in great area on the cell surface, affecting light absorption. Therefore, in order to reconcile between the two factors, Silk 12 busbar technology appears by changing the shape of busbar from rod into tubular (as shown).
With the above characteristics, PV 12 busbar enables:
- Reduce shade caused by busbar on each cell;
- Increase the contact area between the cells with light;
- Reduced light reflection and increase the electrical current generated;
Special welding processes that benefits PV module with less mechanical stress helps reduce the heat convergence point, limit cracks and increase module reliability.
Thus, current PV technology are being developed and improved to increase conversion efficiency, probably up to 25%. For solar power projects, PV is an essential component in the whole system. Supposing that a solar system is a human, PV can be considered as skin protecting other organs. Only with good and high quality exterior part can the interior ones be assured to be well operated. Therefore, investing in solar power system requires choosing appropriate PV based on technical and technological requirements to ensure effective investment. Besides, another factor to consider is cost. With high-tech PV whose cost is usually high, it should be taken into deep consideration to reconcile the two factors to ensure the economic and technical feasibility of the project.