The component decay rate refers to the ratio of the difference between the initial power of the component and the current maximum output power of the component to the initial power of the component. The key to calculating the attenuation rate lies in the measurement of the two parameters of the initial power of the component and the current maximum output power of the component.
The calculation formula is: attenuation rate = initial power of the module / (initial power of the module – current maximum output power of the module) * 100%
The initial power of the module is the maximum output power obtained from the factory test of the module, which is obtained from the solar simulator test in the laboratory of the module factory. The main factors affecting the factory test of components: 1) Ambient temperature: controlled by the air conditioner at 25±2°C; 2) Test equipment: the solar simulator is required to be AAA grade; 3) Calibration and standard components: use calibrated standard components to The solar simulator is calibrated to correct the test results.
The current maximum output power of the module refers to the maximum output power measured after the module has been running for a period of time. Generally, factors such as dust shielding and component defects should be excluded, and the maximum output power of the component itself should be tested. When testing the maximum output power of a module outdoors, the main influencing factors are as follows:
1) Test irradiance: For linear devices, the test should be performed at an irradiance of not less than 800W/m2;
2) Test temperature: For single-glass components with a general backplane structure, the battery junction temperature is reflected by the backplane temperature;
3) Solar spectrum: different regions and environments will have different solar spectra, and the accurate measurement should be corrected with the spectral value of AM 1.5;
4) Module incident angle: Different illumination angles affect the power generation performance of the module, and the impact of incident angle on the test results should be considered during accurate measurement;
5) Test equipment: handheld outdoor test equipment, which needs to be used together with radiation test and temperature test equipment;
6) Reference device: usually a well-packaged WPVS;
7) Correction of test results: According to the IEC60891 standard, the outdoor irradiance and temperature are corrected to the results under STC conditions.