Exploring Contact-Less Cell Cutting Technologies
Why are solar cells cut?
Modules made with half-cut cells have a higher efficiency than full-cell modules made using the same PV cells.
This is because modules with half-cut cells have a lower series resistance loss, and the inter-cell gaps allow more light to reflect off, of the Backsheet, and return to the active cell areas. As a result, the module efficiency can increase by approximately 3% !
However, cutting a solar PV cell in half is a tricky process.
Solar cells are extremely thin (generally between 130 µm and 190 µm), making them highly susceptible to electrical and mechanical damage when subjected to even the slightest pressure.
These damages not only lower the output of the module but also reduce the durability and longevity of the modules.
An excellent way to mitigate these risks is to use a contact-less cutting technology.
Contact-less cutting involves the use of lasers to cut a solar cell. This method eliminates the need for physical contact, thereby minimizing the potential for damage.
Contact-less cutting technologies
As half-cut solar modules become more popular, many new technologies have emerged to minimize the electrical and mechanical damages resulting from the cutting process.
The two prominent contact-less cell cutting methods used at RenewSys' module manufacturing facilities are Laser Scribe and Cleavage (LSC), and Thermal Laser Separation (TLS).
The LSC is a two-step process involving laser scribing of the rear of the cell, followed by mechanical cleavage of the cell. This method cuts solar PV cells in half, reducing the current flowing through them. As a result, resistive losses from transporting energy via current are decreased, leading to improved performance.
The TLS technology, also referred to as Non-Destructive Cutting (NDC), is a damage-free and kerfless (without material loss) dicing technology specifically for brittle materials like silicon. Kerfless When compared to the LSC method, cut cells produced using TLS exhibit slightly better electrical and mechanical performance.
References:
https://thesolarlabs.com/ros/half-cut-solar-cells/
https://www.researchgate.net/publication/282831596_High_Quality_Half-cell_Processing_Using_Thermal_Laser_Separation