- Factors affecting the conversion efficiency of solar cells
(1) The influence of sunshine intensity The influence of sunshine intensity E on the volt-ampere characteristics: As long as the solar spectrum and module temperature remain unchanged, the conversion efficiency is not significantly affected by the sunshine intensity; only when E<0.2kW/m², the efficiency begins to be obvious decline.
(2) The influence of working temperature The working temperature has a great influence on the volt-ampere characteristics of solar cell modules. Under normal conditions, when the temperature rises, the current and voltage ratings will change, but the various indicators are around the standard temperature of 25℃. There is little change with the parameters, which is why the battery test conditions require the temperature to be 25°C. In the engineering design of the photovoltaic system, the temperature correction coefficient should be increased or decreased to make the system work in the best condition.
- Standard solar cell
Standard solar cells are used to calibrate the irradiance of the test light source. The standard solar cell during actual testing is generally AM1.5 working standard solar cell.
(1) Type Standard batteries are usually divided into three levels, namely, primary standard solar cells, secondary standard solar cells, and working standard solar cells.
The first-level standard solar cell usually refers to the national-level standard battery, which is used and maintained by the statutory measurement unit designated by the country; the second-level standard solar cell is based on the first-level standard solar cell and is performed under the specified accuracy of the solar simulator Standard solar cells that are calibrated and copied, usually the company-level standard battery refers to the secondary standard solar cell; the working standard solar cell is based on the secondary standard solar cell, and is used after calibration and copying under the specified solar simulator Standard solar cell for daily testing. The battery usually refers to the battery that is calibrated by the inspector during production.
In addition, there are spectral standard solar cells used to calibrate the irradiance of monochromatic light and standard solar cells with filters. This kind of battery uses monocrystalline silicon solar cells plus appropriate filters to correct its spectral response to It is basically the same as the amorphous silicon solar cell, and can be used as the standard solar cell for the amorphous silicon solar cell test.
(2) Standard test conditions The standard test conditions for solar cells are: ①Temperature is 25±2℃; ②The light source irradiance is 1000 W/m², and it has a standard solar spectrum irradiance distribution.
(3) Standard working conditions The standard working conditions are that the irradiance measured with a standard solar cell is 1000W/m², with a standard solar spectral irradiance distribution, and the solar cell temperature is the battery rated operating temperature (NOCT) of the module.
(4) The rated operating temperature of the battery of the module is 800W/m² with an irradiance of 800W/m², an ambient temperature of 20°C, and a wind speed of 1m/s. The battery is in an open circuit state and sunlight is vertically irradiated to the module installed in the open frame at noon. On time; the measured average equilibrium temperature of the solar cells in the module is called the nominal operating temperature of the module (Nominal Operating Cell Temperature, NOCT).