LeTID stands for Light and Elevated Temperature Induced Degradation of silicon-based PV cells and modules. It is a material based failure mechanism which significantly limits the life time of solar cells due to the light and temperature induced reduction of the cell efficiency. As the degradation varies from cell to cell the effect on the lifetime is not predictable. Therefore the industry requires a standardized test method applicable to a production environment to ensure the quality of the products.
The project was performed by a consortium of 6 partners (Fraunhofer-Center für Silizium-Photovoltaik CSP, Hochschule Anhalt, Wavelabs GmbH, centrotherm international AG, Hanwha Q Cells, DKE Deutsche Kommission Elektrotechnik), 3 associated partners (Mayer Burger AG, LayTec AG, IBC Solar AG) and 1 subcontractor (International Standards Consulting) founded by Federal Ministry for Economic Affairs and Energy (Germany).
The project aimed to understand the degradation process and develop a standardized LeTID test method including their implementation on commonly used LID test equipment. The test method developed in the project was published in a German national pre-standard, called “VDE Anwendungsregel”, under VDE-AR-E 2126-4-100.