PV Operation and Maintenance: Combating Hidden Cracks with el detector

In the process of photovoltaic (PV) operation and maintenance, "hidden cracks" is an important issue that cannot be ignored. It is like a "latent illness" lurking in PV modules, quietly affecting the performance of the system.

I. What are hidden cracks?

Hidden cracks, as the name implies, refer to the fine cracks that occur on the cells inside PV modules. These cracks are usually difficult to detect with the naked eye. They may be generated due to factors such as mechanical stress and thermal stress during the production, transportation, and installation of PV modules. For example, improper handling during the handling of modules or excessive squeezing of the cells during the installation process may trigger hidden cracks.

II. What are the consequences of hidden cracks?

Power attenuation: Once hidden cracks occur in the cells, the internal current conduction path will be affected. The cells that could originally efficiently convert solar energy into electrical energy will have some areas that cannot work properly due to the hidden cracks, resulting in a decrease in the power generation of the entire PV module. According to research, for PV modules with hidden cracks, the power attenuation may reach 10%-30%, which seriously impacts the overall power generation and revenue of the PV power station.

Exacerbation of the hot spot effect: Hidden cracks will increase the local resistance of the cells. Under sunlight exposure, the areas with high resistance will generate more heat. When this situation continues to develop, hot spots are likely to form. Hot spots not only accelerate the aging of the cells and shorten the service life of the modules but may even cause a fire in severe cases, endangering the safety of the entire PV power station.

Premature failure of the modules: Over time, under the combined action of environmental factors (such as temperature changes, humidity, etc.) and electrical stress, the hidden cracks will continue to expand. Eventually, the cells may completely break, leading to the complete failure of the PV module, which has to be replaced in advance. This undoubtedly increases the operation and maintenance costs.

So, how can the photovoltaic industry prevent "hidden cracks"? This is where the following "magic tool" comes in handy.

el detector —— A powerful tool for detecting hidden crack hazards!

The el detector is a highly efficient and accurate PV module detection device. Its emergence is not just for timely detecting the hidden crack hazards in PV modules...

What is an el detector?

The el detector, that is, the Electroluminescence detector. Its working principle is based on the electroluminescence effect of semiconductors. When a forward bias voltage is applied to the PV module, the minority carriers (electrons and holes) in the cells will recombine, and energy will be released in the form of photons during the recombination process, thus generating a luminescence phenomenon. A normal cell will exhibit a uniform and bright luminescence state in the EL image. For a cell with hidden cracks, due to the increase in resistance at the crack, the current conduction is blocked, resulting in a weakening or no luminescence in this area, and black lines or patches will be clearly displayed on the EL image, allowing the detection of PV panels with hidden cracks.

The el detector is a non-contact detection method and will not cause additional damage to the PV modules. It has a fast detection speed and can scan and detect a large number of PV modules in a short time, with high detection efficiency. Moreover, the detection results are intuitive and accurate. Through professional image analysis software, parameters such as the location, length, and width of the hidden cracks can be accurately measured and analyzed, providing a strong basis for subsequent maintenance decisions. In scenarios such as daily inspections of PV power stations and acceptance of new power stations, the el detector has become an essential tool, effectively ensuring the reliable operation of the PV system.