Anti-PID Technology in the photovoltaic

The first studies on the degradation on PV modules performance begun in the seventies but only in the 2000s, with the widespread use of photovoltaic systems, the causes of the early decay of the module performance have been examined.

LID (Light Induced Degradation) is a first phenomenon of performance decay that affects the panel in the first moment of exposure to the sun; this phenomenon stops after some initial diminished performances and the module maintains its own characteristics within the warranty limits.

The second but much more heavier phenomenon is PID (Potential Induced Degradation) due to the difference in tension that is established between the cells and the frame of the modules.

The electric field that develops lead to two type of effects:

• the migration of sodium ions present in the glass toward the cells and the frame
• the polarization of the cells surface.

The first effect changes the characteristic of the cells themselves with a considerable reduction of the generated power, whereas the second effect can be undone by reversing polarity (for example at night).

Significant reduction of the PID phenomenon

The PID phenomenon is significantly reduced in the PV modules that have high quality quartz glass, which by their nature contains small concentration of sodium, with the optimization of the distances and of the EVA layer (the material that encloses the cells); it is thus important to rely on manufacturers of quality modules

In the Book Energetic Systems 4.0 dedicated section

This topic is presented in the section dedicated to photovoltaics on the book “Energetic Systems 4.0 innovative technologies for buildings and mobility” published by VP Solar engineers with the aim to lead resellers, installers and designers towards the evolution of the energetic systems’ market.

VP Solar has also dedicated specific services to support the revamping activities for the technical and product choices when the performances of a PV installation in operation need to be improved