Sustainable Energy

China's Solar Industry

Behind the scenes at Suntech Power, the world’s largest solar manufacturer.

Dec 8, 2011
Suntech Power is the world’s largest maker of solar cells and panels. It reached this position through a combination of clever advances in manufacturing equipment with judicious use of cheap labor, a strategy apparent when Technology Review took a tour of the company’s factories this fall. Above, a worker at Suntech’s manufacturing facility in Wuxi, China, monitors a machine that etches the surface of crystalline silicon wafers for use in solar cells. The machine uses a novel process developed by Suntech that helps solar cells absorb more light.
A worker inspects a wafer that has been treated in a way that helps it absorb more light. 
Silicon wafers are exposed to phosphorous in a hot furnace and then cleaned using a special technique developed by Suntech. These steps allow the wafers to convert light into electricity.
A worker sorts solar cells as they emerge from a machine that adds electrical contacts to their surface. The contacts are the metal lines seen on the surface of the cells.
After the cells are sorted by hand, a machine exposes them to a brief flash of light and measures their response. A robot then sorts them by performance into the bins seen here. 
Workers solder electrical connections to solar cells, so that they can be strung together to make solar panels. Suntech has equipment that can automate this step, but the machines break more cells than workers do, so it’s typically done by hand.
Cells are then soldered together into strings, which are later put together to make complete solar panels.
A string of solar cells is delivered to a station where it will be combined with other strings to make a complete solar panel.
Workers line up strings of solar cells on top of light boxes that allow them to see guidelines. They sandwich the cells between protective sheets and a glass cover, then seal the cells in place inside a large laminator.
As part of quality control, a worker prepares solar panels for a test that will measure their degradation under bright ultraviolet light.