DESTRUCTIVE TESTS

CEP Solar carries out destructive tests to evaluate mechanical and physical characteristics of materials used for PV modules production, in particular EVA encapsulating and sticking properties.

Note:
Destructive tests are only done with Client approval and the quantity of module to employ for the tests is agreed with the Client.

EVA peel strength test

Random samples are taken from different point of the test module.
Peel test is carried out by means of a digital force gauge.

Clamped samples to the force gauge, peeling test from the glass is carried out up as 90°angle from glass surface.

To measure EVA peeling strength from back-sheet the force gauge is fastened on the operating table. The back-sheet and the EVA layer are clamped to the device and the two clamps are moved in opposite directions slowly.

Reading the maximum EVA peel strength from glass and back-sheet detected by the digital force gauge and comparing them with recommended values, it is possible to evaluate if the adhesion value of EVA to the glass and the back-sheet reach the applicable requirements.

EVA pull strength test

Pull test is carried out by means of a digital force gauge. Two sides of EVA sample are clamped to the device and the two clamps are moved in opposite directions slowly until breaking point.

Measuring EVA pull strength at break and comparing it with recommended value, it is possible to evaluate if the EVA tensile strength and the anti-tearing ability reach the applicable requirements.

EVA gel content test

Several fragments of EVA are taken from different parts of test module and the sample is put in a stainless steel net bag

When EVA is heated up during the lamination process, part of EVA cross-links changing his physical state. Extracting by a solvent the part of EVA without cross-linking, it is possible to evaluate the gel content in the sample and compare it with recommended value.

Cross-link rate is an important parameter to evaluate EVA encapsulating properties. The gel content test is done at least for every lot of EVA, or when adjusting process parameters.