Electroluminescence determines cell quality with the help of pictures of solar cells. Voltage is applied to the cell or the module. Current flows “backwards” through the solar cell. This current causes the solar cell to light up (electroluminescence or EL). The strength of the light corresponds to the effectiveness of the solar cell area that is being observed. With a camera that is sufficiently sensitive, it is possible to obtain the effectiveness of the solar cell areas in the form of a picture. If the cell has inactive zones (e.g. due to fractures, finger interruptions, hot spots, small crystals), effectiveness will decrease. This will be represented by dark shadows on the electroluminescence picture.
his method is used for quality control before or after the installation of solar parks. Mobile EL devices can also be used to take measurements on location.
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