Solar cells convert sunlight directly into electricity through the photovoltaic effect. The cells can be used in larger systems in fields and on commercial roofs, contributing to renewable energy supply. As we all know, the solar cell is the main component of a solar PV module, and its value is around 60-70% of the total product. Eco Green Energy only uses Grade A PERC cells for its PV modules. Here, we list the differences between Standard and PERC solar cells for your reference to make good choices of PV modules purchasing.
Standard Solar Cell
A standard solar panel cell contains two layers of silicon, commonly called “n-type” and “p-type” for their negative and positive charge behavior. A solar panel creates electricity when sunlight hits the solar cells, knocking electrons loose from the n-type layer as the p-type layer accepts them, creating an electric field.
(Source: Aurora Solar – A simplified cross-section of a silicon solar cell.)
From the above cross-section, we can see the sunlight (orange) hits the solar cell and the light knocks electrons (blue) loose within the silicon material. Electrons that make their way to the electrical contact can then flow through an attached circuit, providing electrical energy.
(Diagram source: Aurora Solar)
Most silicon modules have layers that help avoid losses. Meanwhile, the front layer reduces reflection losses and prevents electrons from being lost on the front edge. The rear back surface field then repels electrons, reducing the number that makes it to the rear contact.
PERC Solar Cell
PERC stands for “passivated emitter and rear contact” or “rear cell”. Moreover, solar panels built with PERC cells have an additional layer on the back of the traditional solar cells. As a result, this additional layer allows more sunlight to capture and turn into electricity, making PERC cells more efficient than traditional cells. Also, PERC modules are able to mitigate rear recombination and prevent longer wavelengths from becoming heat that would impair the cell’s performance.
(Diagram source: Aurora Solar)
Like other high-efficiency modules, we can use PERC modules to maximize production on a limited roof area. Then, if you are installing on partially shade small roof areas or buildings, PERC modules would be a good option.
Standard Solar Cell VS PERC Solar Cell
Solar cell structure from front to rear side
Standard Solar Cell
Screen-printed Silver paste front contact
Anti-Reflective Coating (ARC)
Silicon wafers that form the P-N junction
Aluminum Back Surface Field (Al-BSF)
Screen-printed Aluminum paste layer
PERC Solar Cell
Screen-printed Silver paste front contact
Anti-Reflective Coating (ARC)
Silicon wafers that form the P-N junction
Local Aluminum Back Surface Field (Al-BSF)
Screen-printed Aluminum paste layer
Dielectric passivation layer
Capping Layer
Moreover, the attributing success of Standard Solar Cell structure is as following:
Obtain simple production technology in comparison to efficiency.
Tolerant structure and process against variations of the quality of the cells.
Readily available production technology, i.e., vital structure elements or process sequences are not severely protected by patents or other legal issues which allowed many manufacturers to compete.
(Sources: AZO Materials)
The dielectric passivation layer contributes to the increase of efficiency by:
Reducing electron recombination – electron recombination blocks the free flow of electrons through the cell, reducing efficiency. The extra passivation layer makes the flow of electrons steadier and more consistent thereby producing additional electric current.
Increasing the solar cell’s ability to capture light – passivation layer reflects unabsorbed light back to the solar cell for a second absorption attempt to produce additional energy making the cells more efficient.
Reflecting specific wavelengths that normally generate heat out of the solar cells. While the rear layer of the solar cell absorbs certain wavelengths by accumulating heat and reducing efficiency. Then, an additional passivation layer reflects these wavelengths out of the solar cell maintaining the temperature of the solar cell.
Conclusion
In a conclusion, PERC solar cell technology is more straightforward as they only differ slightly from the standard solar cells. In addition, it is more cost-effective as it allows maximized energy output due to more efficient energy conversion.
Last but not least, if you want to get more details about solar cells, please refer to our website, or contact us: info@eco-greenenergy.com
