Hot Spot Effect Anaysis On Silicon Cell Modules

With the wide application of solar energy, the installed capacity of PV system is improving. In order to ensure the power generation of the power station, People pay more and more attention to the quality of PV module. There are many factors can affect the performance and lifetime of the PV module, such as EVA yellow, delamination, cracked, PID and hot spot. Hot spot is mainly caused by shadow, cell defects and performance mismatch. Hot spot can cause power loss of module. It can make irreversible destruction such as local burn, melting of encapsulation, burst of the glass when the hot spot is serious. The hot spot of the crystalline is the only issue that related reliability and safety. In order to avoid hot spot, it is important to study the module hot spot and the hot-spot endurance text. Improving the thermal speckle evaluation criteria for the quality and performance of crystalline silicon components.First, make a deep study of hot spot, use Matlab/Simulink to simulate the electrical characteristics of PV module. Analysis the effect of electrical characteristics that comes from the irradiance and environment temperature. Found that the irradiance can make a big influence on the short-circuit current, the temperature make effect on the open-circuit voltage. At the same time, establish the simulation model of module under different shading condition and analysis the change of module electrical characteristics. When the one cell in the PV module is shading, the electrical characteristics of PV modules changed greatly. The Ⅰ-Ⅴ curves presents like the stepladder, and the P-V curves appears many peaks, the total output power change.Secondly, in commercial applications, it is still lack a widely accepted procedure deal with the hot spot and a reference standard that can judge the module with hot spot, which leads to a great dispute in the judge of modules with hot spot in the detection of photovoltaic array. In this paper, In this paper, the thermal spot detection of the actual operation station is carried out by infrared thermal imaging technology, select the temperature anomaly components module. Then taking the following experiment: appearance inspection, EL detection and power detection. Analysis the factors that affect the hot spot:the area and the number of the hot spot. The reasons that cause the hot spot. Found that different reasons with different images, based on this we can judge the origin of hot spot according to the image. And found that relative to the maximum temperature of the hot spot, there is a more direct relationship between the IR difference and the power loss. According to all the above, Standard for judging the hot spots in the spot detection is proposed.