Quality in all Aspects
Accelerated ageing tests are used to determine long-term durability. The quality standards are set out in testing standards IEC 61215, IEC 61646 and IEC 61730. ICOSOLAR® samples, too, are subjected to selective climate testing as well as mechanical, chemical and electrical tests. They are manufactured under near-industrial conditions on professional equipment and can be supplied in sizes ranging from A4 up to large format.
- Climatic Tests
- Damp Heat
At 85°C and 85% relative humidity Icosolar® is tested for at least 2,000 hours as standard practice
At ISOVOLTA, one test cycle consists of 4 days damp heat (= 96h), 2 days TCT (= 8 cycles) and one day HF (=1 cycle). The resulting load totals after 25 cycles are 2,400h damp heat, 200 TC and 25 HF cycles
After 1,524h in the UV weathering test (8h radiation exposure and 4h weathering), the glass-EVA-film samples are exposed to >5kWh/m² in the UV-B range and >50kWh/m² in the UV-A range. In the course of the weathering test, the samples are subjected to a colour measurement, and the yellowing index is calculated from the colour coordinates
- Physical Tests
- Bonding to encapsulating materials
The bonding test is carried out with accelerated ageing in damp heat. A high initial value and adequate stability after weathering guarantee the long module service lives.
Inner layer adhesion
The inner layers adhesion is tested by a 180° peel test before and after 1,000h damp heat.
Bonding to junction box adhesives
In order to test the bonding strength of standard junction boxes it is simulated someone lifting the module by the connecting cable. The adhesive bond has to hold for a defined time. The test is then repeated under damp heat conditions.
Shrinkage / Dimension stability
The dimensions of composite films with a PET core may only change between 0 and 1.5% in the mashine direction and between 0 and 1% in a transverse direction after being exposed to a temperature of 150°C for 30 minutes.
Water vapour transmition
The barrier efficiency is tested using measuring devices with sensitive sensors which can detect even the tiniest amount of water.
Scratching and abrasion resistance
Backsheets are constantly in danger of their surfaces being scratched, cut, or damaged in some other way. Mecanical resistance is therefore tested by a scratch and abrasion test..
- Chemical Tests
- Resistance to chemicals
Resistance to chemicals is an important issue, especially as regards cleaning agents. The backsheet film may on no account dissolve or disintegrate when cleaned with MEK, acetone, ethanol, isopropanol or water following module production. The "solvent rub test" has proved to be a reliable test method. In this test, a cloth is soaked in the chemical and then rubbed to and fro on the backsheet 50 times with a defined pressure. The surface must not be damaged and must not dissolve or disintegrate.
- Electrical Tests
- Breakdown voltage
In order to test the breakdown voltage, a backsheet film is placed between two electrodes and the voltage applied to the electrodes is progressively increased. The breakdown voltage is reached when arcing occurs. Normally, the breakdown voltage is 15-20kV. The material composition and thickness are designed to handle the critical value of freedom of partial discharges.
Partial discharge is a local electrical breakdown which always occurs when the maximum breakdown voltage of an insulating material has been reached due to inhomogeneities. This does not result in total failure of the insulation, but nevertheless it greatly impairs the material's insulating properties. The suitability of a backsheet film to withstand certain system voltages without any great difficulty is measured by a parameter called resistance to partial discharge. Nowadays the standard requirement is >1,000V and this is checked by approved high-voltage testing institutions.