Technology Solar Cells | Solaria

Photovoltaic Cells

The Company has designed a production line of solar cells so that it can accept wafers (a thin coat of silicone semi conductor material), both high productivity mono-crystalline and poly-crystalline that reaches an efficient minimum of 15% in standard testing conditions. The production of solar cells is one of the most complex technological tasks on the photovoltaic production line.

Below is a summary of the most important steps in the production process of photovoltaic cells:

• Quality controls before production. Solaria carry out a series of previous checks on all the wafers obtained from other suppliers. The quality of the wafers is a key factor in the production of the cells and those damaged or defective are removed before being used on the production line.
• Texturising. Each wafer is subjected to a chemical process called “texturising,” where the wafers are cleaned, graduated and rinsed. Once the superficial treatment is finished, they are dried by hot air.
• Diffusion oven. Then a coating with a negative charge is applied to the bulk wafers that have positive charge in a diffusion oven at a temperature of 800 to 900 degrees centigrade, using gaseous phosphorous. This process that is often known as “doped,” creates two separate layers within each wafer: one layer with a negative charge and another with a positive charge below it. This positive-negative field is what allows the solar cell to generate electricity when it is exposed to the sunlight.
• Elimination of the silicon glass edges with phosphorous. To obtain a clean separation of the negative and positive layers, the edges of the wafers are isolated by using a graduation technique by plasma.
• Silicone nitrate coating. So that the cells are able to capture the largest quantity of sunlight possible, they are covered with a layer of anti-reflective silicon nitrate, reducing the reflection indexes. Then cameras are used to check the homogeneity of the heat of the coated cells.
• Contacts. To capture the electric energy created by a solar cell, layers of electric contacts are fixed to allow the electric current to flow towards the inside and the outside of the cell.
• Classification. Then a solar simulator is used to check the power production levels and efficiency for each finished cell and then the cells are classified according to the results and optic criteria. The cells are tested both in standard sunlight and low sunlight conditions.