In general, the cracks of solar panels are not directly detected by the naked eye, and they need to be observed by El imaging and other detection methods. The hidden crack will lead to the decrease of the power generation of the battery module. In severe cases, it will also cause the hot spot effect, which will affect the service life of the entire PV module. Here is why the solar panel will be cracked.
1、 Causes of cracks in solar panels
1. Raw material defects
The defect of raw materials is the main factor that causes hidden cracks in components. The quality of raw materials of battery chips directly affects the quality of products. The cells are produced by growing, cutting, printing and sintering silicon rods. Insufficient purity of crystalline silicon, too large curvature of crystalline silicon battery and too large horizontal and vertical shortening rate of EVA material will all cause hidden cracks in the production of battery modules.
2. Production process error
In the production of battery modules, sorting, single series welding and lamination are required. Framing, cleaning, curing test, packaging, etc. The use of incorrect process in the production process will also constitute a crack in the battery module. For example, during single welding, the temperature of the welding heating plate is too low, the welding temperature is too high, the welding speed is too slow, the lamination parameter setting is unreasonable, and the vacuum pressure is too large or too fast, all of which will lead to hidden cracks in the components.
3. Improper equipment setting
During the production process of battery modules, the series welding machine, laminating machine and framing machine all directly exert force on the battery modules. If the equipment output is improperly set or the equipment is faulty, it will form a hidden crack of the battery modules. If the iron head used in the single series welding process is not treated in time after long-term use, the concave part of the iron head will be uneven, resulting in uneven force during welding, resulting in hidden cracks in the battery module.
4. Manual operation error
There are many hidden cracks caused by human factors in battery modules, which occur in production, transportation, equipment operation and maintenance and other links. Although many automatic equipment are used in production now, manual transfer and fixation are still required in the processes of lamination, framing and cleaning, and finger pressing will be caused in the transfer process. The journey of loading and unloading goods is not firm and constitutes a hidden crack. Other workers’ equipment and nonstandard operation in the cleaning process will also cause hidden cracks in the components, such as the construction personnel stepping on the equipment on the components; The operation and maintenance personnel shall stand on the components to sort out the nonstandard operations such as components.
5. Climate and environmental impact
In the application process of the battery module, due to the impact of the environment, it will also constitute the hidden crack of the photovoltaic module. For example, violent shaking of components in strong wind climate; After heavy snow, the component surface receives uneven pressure from the snow; In hail climate, the components may be cracked due to the severe impact of hail.
2、 Methods of preventing solar panel from cracking
1. Strictly control the incoming quality of the battery, and reasonably select the thickness, hardness and weldability of the interconnection strip.
2. The ambient relative humidity shall be lower than 60% to ensure that the battery is fully preheated before welding.
3. Technical welding shall adhere to light, fast and flat gestures to prevent false welding and over welding, and to prevent pressing the battery, especially on the series welding template.
4. The welding quality of machine welding shall be strictly monitored to prevent false welding, over welding and welding strip deviation.
5. Pay attention to the El check before lamination, and repair the cracks before lamination as much as possible to prevent the expansion of cracks caused by lamination.
6. After laminating, the components shall be fully cooled before edge cutting. It is advisable to use the glass face down method for edge cutting and framing.
7. The laminated parts before framing shall be prevented from overturning and manual transfer.
8. The worktops for trimming and pre framing shall be large enough. After the components are placed in the center, the distance from the edge to the edge of the worktops shall be greater than 200 mm. 20W polycrystalline solar energy
9. When tightening the cover of junction box, the force shall be appropriate, and a large area of support shall be set in the corresponding direction under the table.
10. Steel frame pallet or double-layer wooden pallet should be selected to turnover flat components. When using hydraulic truck, the fork should completely pass through the pallet. Solar panel
The above is the introduction about the causes of the hidden cracks of solar panels. The small area of hidden cracks has little impact on the battery modules, but it does not mean that this problem can be ignored. Therefore, it is necessary to do a good job to prevent problems.