The superstrate, which literally means the top layer, is the protective covering on the upper side of a photovoltaic module that faces the sun. The passive component plays a crucial role in the functionality of a solar cell. The main purpose of adding this protection is to safeguard the cell from the negative impact of weather and other environmental factors. It simultaneously ensures the optimal transmission of the necessary wavelengths of the solar spectrum.
Properties of Superstrate
Here is a brief description of the properties found in a superstrate to be used as the protective covering for a PV module.
1. Impact and Abrasion Protection: The primary function of this superstrate is to shield the front surface of the cell from potential damage such as impact, abrasion, and scratches. Transportation and maintenance activities often give rise to such situations.
2. Electrical Shock: This material needs to possess a high breakdown voltage in order to provide effective protection against electrical shock.
3. Light Weight and Recyclable: Just like any other equipment, our panels need to be lightweight, thus superstrate needs to be lightweight. Adding a heavy superstrate to the panel can make them heavier. Superstrate materials should be eco-friendly and Recyclable.
4. Protection against Wind and Sand: Flexural can be caused by wind and physical handling leading to microcracks within the solar cells. The solar panel is also susceptible to sandblasting caused by the wind. In a windy and dusty environment, the superstrate acts as a shield, safeguarding the front surface from abrasion.
5. Self-Cleaning: The superstrate will be subjected to dust, silt, smoke, snow, and other elements. Thus, they should have a self-cleaning surface or, a surface that can be easily washed.
6. Temperature Resistance: The material used as the superstrate must have the ability to withstand extreme temperatures at the operational location.
7. Transparency: This covering must have high transparency to ensure the optimal transmission of solar energy to the cell below.
8. Weather Protection: The Superstrate needs to provide protection against the elements of weather as Perovskites are highly susceptible to water. Both water, smoke, salt (in coastal areas), and water vapor have the potential to induce the corrosion of various materials.
9. Withstand Ultraviolet Radiation: It can undergo both chemical and physical changes when exposed to ultraviolet radiation, which possesses significant energy. Such exposure can lead to changes in color and opacity.
Also See: What is Module Derate Factor?