How are photovoltaic cells made?

Photovoltaic panels use photovoltaic cells, which are made of silicon crystalline wafers. Silicon wafers can be polycrystalline or monocrystalline and are manufactured using several different production methods. Currently, the most efficient type of cells are monocrystalline cells, which are produced using the Czochralski process. The Czochralski process is widely used to produce monocrystalline photovoltaic cells, particularly silicon cells. This method produces monocrystals with high purity and homogeneous structure, resulting in better performance and quality of photovoltaic cells.

Cell production

The production of silicon-based solar cells requires a number of processes, starting with a raw material called quartzite, which is a form of quartz sandstone.

The production of monocrystalline cells consists of the following stages:

1. Silicon crystals are dissolved in a special crucible. After melting, a mass is obtained to produce a uniform crystal of high mass.
2. A small monocrystal, the so-called embryo, is introduced into the liquid mass. This acts as a starting point for the growth of the monocrystal.
3. An ordered quartz-crystal structure grows around the embryo.
4. The process of crystal growth involves slowly pulling the embryo out of the liquid mass while rotating it, resulting in the gradual deposition of liquid atoms around the embryo - creating a monocrystalline shape.
5. The core thus prepared is cut into the form of a block with rounded corners. This is the stage where it is prepared for further processing.
6. Using a steel thread or a laser, the block is cut into even slices. Each slice is approximately 0.1 to 0.3 mm thick.
7. This produces wafers with a charge of p. To create a working module, some of the wafers are subjected to additional processing. They are enriched with elements that easily lose electrons, e.g. phosphorus, to produce wafers with an n charge.

How does the size of monocrystalline cells affect performance and cost?

Larger monocrystalline cells may have the potential to generate more electricity. The larger the individual cells, the greater the percentage of working surface area in the entire panel. The larger cell area allows more sunlight to be collected and converted into electricity.

Size does, however, affect price, as the manufacturing cost of the cells is proportional to the cell diameter. From a practical point of view, however, the size of the cell does not matter much, as the size and power of the entire cell system, i.e. the solar panel, determine the relevant parameters for the installation.