I. Introduction to Solar Panels
A solar panel is a device that absorbs sunlight and converts solar radiation energy directly or indirectly into electrical energy through the photoelectric effect or photochemical effect. Most solar panels are primarily made of silicon, but their widespread use is limited due to their high manufacturing cost. Compared to ordinary batteries and rechargeable batteries, solar cells are more energy-efficient and environmentally friendly green products.
II. How long is the lifespan of solar panels?
Tempered glass laminated solar panels have a lifespan of 25 years, PET laminated solar panels have a lifespan of 5-8 years, and epoxy resin encapsulated solar panels have a lifespan of 2-3 years. Currently, over 95% of solar panels on the market are tempered glass laminated solar panels from companies like Risen Energy.
The lifespan of a photovoltaic module is determined by its power generation efficiency. The degree of bonding of the PN junction and the purity of the silicon wafer determine the intensity of electrical energy generated by the solar panel under the same light irradiation. Over time, the PN junction will break down, and the efficiency will continue to decline. After 15 years, the conversion efficiency will be over 90%, and after 25 years it will drop to about 85%. Therefore, the lifespan of a photovoltaic module is basically over 20 years.
The main influencing factors are as follows:
1. Hot spot effect
The hot spot effect refers to the phenomenon where, during a normal operation of a battery module, a single cell is covered by a small object at a certain moment. This reduces the current generated by that single cell. A single cell in a battery module can be considered as a PN junction structure similar to a diode, exhibiting reverse avalanche breakdown. According to Kirchhoff's current and voltage laws, when the current generated by the covered cell is less than the circuit current, that cell becomes negatively charged, acting as a load. It then dissipates the energy generated by other cells as heat.
The hot spot effect is also closely related to the manufacturing process of battery modules. Due to defects in manufacturing processes, uneven internal resistance often occurs in individual battery cells. Cells with uneven internal resistance are highly susceptible to hot spot phenomena.
Hot spot effects are extremely harmful to solar cells. At best, they can burn out the individual cells; at worst, they can cause the entire solar module to burn.
2. Impact of environmental factors
Temperature, light radiation intensity, wind load, and snow and ice load can also affect battery life.
III. Life Cycle of Solar Panels
Solar panels have a long lifespan; some installed in the 1890s can still generate clean electricity—but their durability comes from their economic cost.
To ensure that solar panels have a lifespan of 25 years or more, various expensive sealants and protective layers are used on them.
To help protect fragile crystalline silicon solar cells installed inside modules, many manufacturers use expensive EVA adhesive as a coating. Researchers at the Fraunhofer Center for Sustainable Energy Systems (CSE) in the United States have been investigating alternative, cheaper materials that can be used in solar cells.
One of the materials is silicone resin, which is neither an inorganic crystal nor an organic polymer, but is related to both. It should not be confused with silicon; silicone resin is inert and is a compound artificially synthesized in various forms and for various applications.
While various silicone resin mixtures are used to encapsulate photovoltaic modules, this material has not yet been widely used in laminated solar cells themselves.
Fraunhofer researchers have prepared a prototype of a silicone laminated solar cell and placed it in an artificial climate chamber under low temperature and cyclic loading. The cell was then tested using flash and electron fluorescence imaging techniques.
Compared with traditional solar cell modules, the silicon-coated photovoltaic cells are more resistant to cyclic loads when subjected to strong winds, especially at ultra-low temperatures of -40 degrees Celsius.
In other Fraunhofer news, the organization has announced the official launch of OTF-1, a new outdoor photovoltaic test site in Albuquerque, New Mexico. As an extension of the existing Albuquerque Solar Research Center for Sustainable Energy Systems (CSE), the facility will greatly assist photovoltaic module and component manufacturers in assessing the real-world performance and durability of their products, as well as helping system integrators collect crucial data on performance and lifespan expectations.
The Fraunhofer Society is the largest application-oriented research institution in Europe. It comprises more than 80 research entities, including 60 Fraunhofer Institutes in various locations in Germany, as well as research centers and representative offices in other parts of Europe, the United States, Asia, and the Middle East.
IV. Routine Inspection and Maintenance of Solar Panels
1. Check the solar panels for any damage and replace them promptly if any is found.
2. Check whether the solar panel connection wires and ground wires are making good contact and whether there is any looseness.
3. Check if there is any overheating at the junction box wiring points.
4. Check the solar panel brackets for any looseness or breakage.
5. Check and clear away any weeds that are obstructing the solar panels.
6. Check the surface of the solar panel for any obstructions.
7. Check the surface of the solar panels for bird droppings and clean them if necessary.
8. Assess the cleanliness of the solar panels.
9. In windy weather, the solar panels and their supports should be thoroughly inspected.
10. In heavy snow, the solar panels should be cleaned promptly to prevent snow and ice from accumulating on their surface.
11. During heavy rain, check all waterproof seals to ensure they are in good condition and there are no leaks.
12. Check if any animals have entered the power station and damaged the solar panels.
13. In hail weather, the surface of the solar panels should be thoroughly inspected.
14. Detect the temperature of the solar panel and analyze it by comparing it with the ambient temperature.
15. Problems identified during inspections should be addressed promptly, and analyses and summaries should be conducted.
16. Detailed records should be kept for each inspection to facilitate future analysis.
17. Conduct analysis, summarize, record, and archive the findings.
