Solar cells are cut into the required size so as to get the desired output from the solar pv module. This is done by a machine called Laser cutter.
Setting up electrical connections between strings of solar photovoltaic cells involves the stringing process. Cells are stringed together using automated stringing equipment’s (Stringer with two robots and inspection units) employing pre-programmable software.
This step involves linking the cell strings in series or parallel with bus ribbons, in order to give the required shape to the module prior to encapsulation. Strings of cells are laid in proper configuration and each string is connected with bus ribbons to form one interconnected solar module.
EVA and back sheets are cut by automatic cutting machine. There are five layers to a solar module comprising of the following:
e. Back sheet
Once the lay up is done then the module is put through an EL machine where the quality of the cells used in the module is checked and incase there is any cell crack, black cell etc then the same is replaced with a fresh cell.
After EL testing, the PV laminator bonds the multiple layers of material with thermoplastic films and a vacuum process ensures the complete encapsulation of the photovoltaic materials. The interconnected solar PV cells are laminated with clear polymer-like material in highly automated laminators.
In the next stage the excess polymer sheet is trimmed off from the sides of the laminate with the help of a heated knife.
Anodized aluminum frames are then put on the four sides of the laminate with the help of sealant so as to ensure that the laminate is free from dust, water seepages or other unwanted matter. These aluminum frames have pre-fabricated holes so as to ensure proper and easy installation at the site.
Fixing a junction box and connection cables to rear side of each polycrystalline solar module comes next. This enables easy electrical integration among modules in the installation site. An electrical connection junction box is mounted and sealed to the back of the module using high quality sealant.
Once the junction box is fixed to the module then the module is ready and is put through a sun simulator for power output testing under standard test conditions.
Once the module is tested and QC passed then the modules are packed for delivery to the customer.