In today’s world of electronics and PV applications, the components may have to be used under very harsh environmental conditions. The 85/85 test describes a standardized procedure to determine the resistance of materials, coatings, and encapsulated devices to moisture and thermal stress exposures. It regards those samples under exposure to high temperature combined with high humidity, which subsequently reveal phenomena such as delamination, corrosion, insulation failure, and effects on optical or electrical properties. This is often conducted during quality assurance processes concerning semiconductors, solar panels, LEDs, or other sensitive assemblies.
Principle and Methodology
The core idea of 85/85 tests is to quicken aging and moisture absorption by placing samples in a controlled chamber with 85°C and 85% relative humidity for a set time, often ranging from 500 to 1000 hours. The tests usually precondition the samples and monitor electrical properties continuously with periodic evaluation for any physical manifestation of degradation, such as cracking, fogging, or discoloration. In many situations, the samples are biased electrically during the test to resemble the working conditions and provide better chances of observing a failure mode that might occur during field use.
Instrumentation
The experiments are performed in environmental chambers with accurate temperature and humidity control. These chambers enable uniform environmental conditions that exhibit very low fluctuation. For active devices, setting up may include power supplies and monitoring equipment to apply and track electrical bias during the test. Oftentimes, data loggers and imaging devices are used to capture test progress and visually document any material changes. Modern test chambers may include alarm systems to ensure rapid intervention in the event of deviations from preset conditions.
Strengths and Limitations
Testing Precision 85/85 is a great choice for an early detection tool considering material and design vulnerability. Exposure for long periods in a real-life simulation of field conditions, which most components will see over the years, enhances the chances of latent failures occurring in real-world environments. There are definite downsides, such as the time involved in these tests and the possible different modes of failure between accelerated aging mechanisms and real field failure. The method does not apply to all types of materials, especially those that will, unless to determine failure threshold, not survive in humid environments for a very short duration.
Conclusion
The Precision 85/85 test has become the cornerstone of environmental reliability testing for electronics and photovoltaic systems. It provides manufacturers with an opportunity to assess the durability of encapsulation, coatings, and assemblies by subjecting materials to high humidity and heat for prolonged periods. If this test is applied rightly to support the durability of products that withstand the operational stresses imposed on them, it leads to greater customer satisfaction and lower maintenance over time.
