Why Do Backsheets Matter?
Photovoltaic backsheets play an important role in protecting solar modules over their lifetime. Some of their key functions include:
- Physical protection
- Moisture protection
- Electrical insulation
- Color that helps modules blend into their surroundings
- Efficiency to help modules generate more power
Module makers have a wide choice of backsheets. They all use different components and constructions. Selecting the right backsheet for a specific module design is often complex, time-consuming and expensive. But, making the right choice can ultimately impact your module’s ability to perform.
Backsheets Allow Modules to Operate Safely
Photovoltaic modules can operate at temperatures of 90ºC or higher. Backsheets insulate the electrical components of the module, ensuring they can produce electricity safely. A backsheet’s safety performance can be evaluated by looking at two key tests:
Breakdown voltage test: This test evaluates the voltage level that causes permanent failure of the backsheet and significant loss of electrical safety. The higher the breakdown voltage rating, the safer the backsheet. Low breakdown voltage can compromise module safety, resulting in potential shock or fire hazards
Wet leakage test: Measures the panel’s ability to keep electricity isolated within the proper components of the panel. If a panel fails a wet leakage test, it can mean that the module’s safety can become compromised in very wet conditions, such as melting snow, heavy rainfalls, condensing humidity and panel cleanings.
Learn more about the safety of your backsheet.
Backsheets Help Modules Produce Power Efficiently
Photovoltaic (PV) modules need to be a reliable source of power for 25 years or more, so their components all need to work in concert to ensure the panel continues to perform. Backsheets help do that – they insulate the electrical components of the module, protecting them over their lifetime.
You can judge backsheet performance by:
UV light can cause degradation: A UV aging test can determine whether a backsheet is more likely degrade and become yellow. Yellowing can also indicate a compromise in reflectivity, which can lead to decreased performance.
Embrittlement of PET layer: A brittle backsheet may crack under mechanical stress, causing the module to fail.
Delamination of backsheet and backsheet adhesive: Delamination of the backsheet layers or adhesive can decrease module performance, especially in harsh weather conditions.
Learn more about the performance of your backsheet.