1, component quality
Due to factors such as cell cracking, black core, oxidation, and virtual soldering, as well as material defects such as backplane and aging of long-term use, the power of the component is affected during long-term operation, resulting in low power generation of the module. It is noteworthy that the crystal structure of the single crystal determines its superior performance in resisting cracking.
2, PID effect
During the long-term work of the external components, the water vapor permeates into the interior of the module through the backing plate, causing the EVA to hydrolyze. The acetic acid ions cause metal ions to precipitate in the glass, resulting in a high bias voltage between the internal circuit and the frame of the module, resulting in electrical degradation. The amount of power generation has dropped dramatically.
3, solar racking component installation method
From the total amount of solar radiation on the inclined surface and the principle of direct dispersion of solar radiation, the total amount of solar radiation Ht on the inclined surface is composed of the direct solar radiation amount Hbt sky scattering amount Hdt and the ground reflected radiation amount Hrt, namely: Ht = Hbt + Hdt + Hrt. In the same geographical location, due to the difference in the solar racking installation angle, the cumulative amount of absorption of sunlight is different, and the cumulative difference in the amount of radiation causes a difference in power generation.
4, weather factors
The weather is also one of the factors that affect the power generation efficiency of the components. In the rainy weather and thicker clouds, the intensity of sunlight is reduced, the solar light absorbed by the cell is less, and the power generation is reduced. The low-light response of single crystal is better than polycrystalline under low irradiation. In the case where the conversion efficiency of the solar cell module is constant, the amount of power generated by the photovoltaic system is determined by the radiation intensity of the sun. The amount of electricity generated by a photovoltaic power plant is directly related to the amount of solar radiation. The radiation intensity and spectral characteristics of the sun change with meteorological conditions.
5, shadow blocking
During the working process, due to the partial shadow of the shadow and the degree of dust settlement, the pollution of bird droppings will cause the “hot spot effect”. The occluded part will not provide power contribution and become energy-consuming load inside the component, and cause The local temperature of the component rises, and the overheated region can cause the EVA to accelerate aging and yellowing, so that the transmittance of the region is lowered, thereby further worsening the hot spot, resulting in an increase in failure of the solar cell module.
6, temperature coefficient
The temperature coefficient of the crystalline silicon battery is generally -0.4% to -0.45% / ° C, and the single crystal temperature coefficient is smaller than polycrystalline. Changes in the ambient temperature and the heat generated by the components during operation cause the temperature of the components to rise, which also causes the power generation of the components to decrease.
7, clean and maintenance
When the components are in the field for a long time, dust and other debris will fall on the glass, and a large amount of dust or dust will settle for a long time, which will weaken the penetration of sunlight and cause the surface temperature of the component to rise and affect the power generation efficiency of the component. When the surface of the component is dusty, the difference between the power generation before cleaning and the cleaning is 5.7%. If the cleaning is not carried out for a long time, the difference in the amount of dirt generated in the surface of the component can reach more than 10%.
The above analysis only affects the power generation of the components from the components themselves and external environmental factors. In addition to the factors mentioned above affecting the power generation efficiency and power generation, there are also components in the working process due to the electrical system and other factors. Power attenuation, power generation reduction, etc., follow-up process improvement, technology improvement, material development and more related research to solve and improve the factors affecting component power generation.