The first thing solar investors look into PV models is outdoor reliability and efficiency. Since the panels are installed outdoors, the ability to withstand harsh weather conditions and the potential to perform are significant indicators of quality panels. A solid understanding of the solar panel circuitry, photovoltaic device design, and thermal resistance is crucial to identify whether a panel will be affected by such degradation or not.
The term “LID” (Light Induced Degradation) is commonly used in solar panel installation literature and industry trade journals as a synonym for thermal shock. However, it is a misnomer because the term LID has several inherent differences from that of Thermal Shock.
In this blog, we will clarify those differences – LID refers to a degradation of performance and quality due to direct light exposure during the initial hours of panel setup. It can indeed constitute an early degradation concerning the panel factory flash-on test data received from some PV panel manufacturers. For example, if sunlight is directed directly at the panel electronics, a small amount of heat may cause them to buckle, warp or break down.
What makes this degradation so damaging to your solar panel system is the fact that its energy is very low in comparison to the direct heat from the sun’s photons. That is why most PV cells fail the initial Factory Flash On tests during setup.
As stated earlier, LID has multiple forms. One of those is the degradation of the photovoltaic devices through the use of a thin layer of crystalline silicon oxide, which is referred to as the crystalline silicon oxide layer. Another type is called “direct light-induced degradation” (DLID), which is the degradation of photovoltaic cells from direct exposure to direct sunlight. The main difference between “DLID” and “LID” is the duration of the degradation. While the duration of a single solar panel exposure may be relatively short, “DLID” degradation may last a few hours, while”LID” degradation may last a few days or even more than a week.
When you compare the effects of LID and DLID, the two types are often compared based on how much electricity they generate during direct exposure to direct sunlight. The honest way to judge the comparative effects of the two is to consider how much power a person would have to generate for a complete charge and discharge cycle to completely saturate one or both of the photovoltaic devices.
When looking at the life cycle of a silicon PV module, the solar investor needs to keep an eye out for the different types of degradation that can be caused by the various UV lights and other environmental factors. The main degradation that we will look at here is the LID in crystalline silicon solar cells and the crystalline amorphous silicon solar cell degradation. The LID in crystalline silicon solar cells is caused by the reduction of photovoltaic efficiency at the initial stages of exposure to sunlight light. This is commonly referred to as “UV light-induced degradation” (UVID). This LID in crystalline silicon solar cells is typically associated with the formation of the boron dioxide complex which forms a dangerous oxide in the presence of sunlight and gradually reduces the carrier mass.
On the other hand, crystalline amorphous silicon solar cell degradation is caused by the interaction of the crystal structure of crystalline amorphous silicon cells with the outside environment. There are several different types of amorphous silicon solar cells that have different characteristics. Most of these types of amorphous silicon solar cells have low energy conversion rates. Therefore, it has been a major concern among photovoltaic manufacturers who have introduced different technologies to reduce this degradation. The most popular method involves the use of the semiconductor material called Silicon Dioxide or Silicon Oxide.
To understand the process of degradation in solar panels, we must understand the difference between a chemical process and a mechanical one, which means that to understand degradation we need to know the basic parts of solar panels. These are the panels that catch the light from the sun and convert it into usable energy and this is what allows us to utilize the solar energy to heat water, use it as a power source or to produce electricity. If a part of the panel is damaged, then the sunlight would not be able to pass through the damaged area and would have a much lower efficiency than it did previously.
Why is it crucial to test panels for LID?
LID can be primarily witnessed in panels with silicon solar cells particularly in PERC modules. It can result in a devastating loss in the conversion and generation of electricity because of the recombination active defects during the extra carrier injection by illumination. This testing helps ensure the performance of PV modules in their entire product life cycle. Therefore, evaluating LID is of paramount importance for cost-effectiveness and power conversion.
This test of solar cells is usually done during the early stage of manufacturing. It is very critical for quality assurance and reliability during panel production. The three testing techniques which are mainly used are LED techniques, LID stabilization test and electrical carrier injection.
Why should you use Novergy panels?
To combat these degradation issues, it is important to use solar cells and production processes that ensure low levels of LID. If you fail to do so, then the performance loss of panel ranges between 1-5%. Generally, monocrystalline cells have high-efficiency components and are more prone to get affected.
We at Novergy, carefully adhere to the standards and protocols set by the solar authorities to make sure the nominal power of the panel equates to the real power output. Our panels go under stringent performance testing to withstand the unfavourable weather conditions and to deliver outstanding conversion. To know more about our products and multiple solar solutions, please visit novergysolar.com.