Examining solar panel supplies on the microscale

Before making the funding in an array of solar panels, potential consumers could surprise: How lengthy will the expertise final earlier than it breaks down?

That’s simply what a group of NIST researchers—together with Stephanie Moffitt, Po-Chang Pan and Xiaohong Gu (proven right here)—got down to perceive.

Nowadays, 30- to 35-year warranties are the norm for industrial solar panels, however there are considerations that some solar panel supplies can present cracks and fail earlier.

For their exams, the group members used a number of accelerated weathering protocols to simulate growing old within the discipline, exposing their samples to stressors similar to warmth, humidity and ultraviolet light. They additionally had samples taken from a solar panel discipline in Arizona after seven years, which is when the panels began to indicate cracks.

They discovered that cracks may type within the backing materials (backsheets) of panels utilizing a sort of polyvinylidene fluoride (PVDF) polymer as a laminate, particularly when:

• The polymer is mechanically careworn (pulled or stretched) in a particular path, which weakens the crystalline construction of the fabric.
• The outer layer is mixed with acrylic polymers and pigments, which results in chemical degradation that produces floor pits. The backsheet then can not stand up to pressure, and the pits trigger micro-cracks.

Using microscopy methods, the researchers additionally found a change in a backsheet materials’s crystalline construction that occurs throughout cracking. That construction transitions from alpha to beta phase, that means the polymer chains start packing in a extra aligned formation.

In quick, the group discovered that not all PVDF-based backsheets behave the identical, and lumping all of them collectively could oversimplify the state of affairs.

In many circumstances, backsheet cracking generally is a large drawback for solar panel vitality, and it would not have a widespread, easy repair. Panels with extreme cracking require an entire alternative. But this kind of analysis supplies extra perception into the issues in order that producers could make extra knowledgeable decisions about supplies for extra dependable merchandise.