German Solar Panels in India | Sustainable Urban Development

HOW SOLAR PANELS ARE MADE

Ben visited Vikram Solar’s factory in Falta, West Bengal, to see how a solar panel is produced. Vikram Solar is the company that installed the solar power plant at the Cochin International Airport which has more than 46,000 PV panels, making it the first airport in the world to operate solely on solar energy! Let’s get the details from Ben on how solar panels are made!

How are solar panels made?
With friendly support from Vikram Solar Pvt Ltd

STRINGING

Soldering operation connecting the negative side of a solar cell to the positive side of a consecutive cell like a chain with help of copper interconnect ribbons. Thus, it forms a string of 6/8/10/12 cells depending upon the configuration of the solar panel.

LAYUP-I

The stringed cells are laid up on the front encapsulant layer (ethyl vinyl acetate) over a low-iron tempered glass.

BUSSING

The strings are connected with help of copper bus ribbons as per the polarity of cells in each string and the output terminals are taken out. Proper insulators are placed in between the bus ribbons to avoid short circuiting.

LAYUP-II

Another encapsulant layer, same as that on the front, and a three-layered PV backsheet is put on the rear side. Output terminals are taken out through this backsheet, making a slit. Thus, a sandwich is formed that is ready for lamination under certain temperature.

LAMINATION

The sandwich is subjected in a chamber called laminator under requisite temperature for a fixed time cycle. The EVA melts and binds the sandwich components together with its gel. The sandwich comes out as a single unit post lamination.

FRAMING

This solar laminate is framed with “anodised” aluminium frames to enable mechanical strength. Framing is done with a glue called silicone sealant. Curing takes up to 8 hours.

JB FIXING

The output terminals taken out during bussing are fitted across metal plates/rails of a junction box which is fixed on the backsheet of the photovoltaic module through sealant application. This junction box is enabled with two copper-insulated cables that have two connectors, one as positive and the other as negative.

CLEANING

After curing, the modules are thoroughly cleaned with acetone and stacked on pallets to be readied for flash testing.

FLASH TESTING

Before flash testing, the modules are cured and cooled for around 4 hours to attain 25°C. Once cooled, the module is flashed using a sun simulator with an artificial Xenon light source, emitting light at 1000W/m2 irradiance. This action generates a current-voltage (IV) curve, stating all the electrical parameters like maximum power, open circuit voltage, short-circuit current.

ELECTROLUMINESCENCE TEST

The module is subjected under forward bias where the solar cells act as an LED and emit a light that is captured by an EL camera. The captured image depicts whether any low-performing cell, dead cell, microcracks, cross cracks, wafer-related defects are present or not.

FINAL QUALITY CONTROL

Before packing, the modules are checked aesthetically and proper gradation is done as per acceptance limits.