Climate specific accelerated ageing tests

Eder, Gabriele; Voronko, Yuliya; Knöbl, Karl; Dimitriadis, Simon; Újvári, G.; Berger, Karl; Neumaier, Lukas

doi:10.1109/pvsc40753.2019.8981293

Cited by 4 publications

(6 citation statements)

References 6 publications

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“…Looking at the EL images of the test modules with differing encapsulants (EVA, TPO and POE) before and after DH storage (see Figure 9), it can be seen that the only sample showing dark areas in the grid finger region is the test module with the EVA encapsulant after prolonged storage time. 56 The test modules comprising the polyolefin backsheets POE and project, the similar modules just with EVA as encapsulant were exposed also for longer times; see Eder et al 57 Therefore, for longer exposure times, these dark areas were paralleled by an increase in the serial resistance and decrease in power. 57 3.3 | Discussion: Assessment of suitability…”

Section: Module Testingmentioning

confidence: 99%

“…In order to identify the processes/surface species giving rise to the black (inactive) cell areas of the EVA/PPF test modules after DH storage, the module was dismantled and FTIR spectra were taken of the encapsulant surface covering the inactive cell areas. The difference spectra (seeFigure 10)of the encapsulant taken from above the ribbon and above the cell correspond to those of Pb acetate56,57 ; others agree very well with reference spectra of Ag acetate, indicating the reaction of the degradation product of EVA, acetic acid, with the solder material (Pb) and grid finger metallization (Ag).F I G U R E 5 Coefficient of thermal expansion of encapsulant films EVA, TPO and POE in their original state (uncured). EVA, ethylene vinyl acetate; POE, polyolefin elastomer; TPO, thermoplastic polyolefin [Colour figure can be viewed at wileyonlinelibrary.com] Thus, direct evidence for the formation of acetic acid and lead acetate in the encapsulant EVA was found from FTIR measurements.…”

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confidence: 99%

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Properties and degradation behaviour of polyolefin encapsulants for photovoltaic modules

Oreški

Omazic

Eder

et al. 2020

Progress in Photovoltaics

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Various types of next-generation encapsulation films based on polyolefins have recently been introduced and could attract market attention. These material innovations can be classified as polyolefin elastomer (POE) and thermoplastic polyolefin (TPO) encapsulants, both of which consist of a polyethylene backbone with different side groups. The main advantage of these materials is the replacement of the vinyl acetate side groups of state-of-the-art encapsulant ethylene vinyl acetate (EVA) so that acetic acid cannot be formed. The main objective of this paper is to investigate the material properties of next-generation encapsulant films and compare them to an EVA reference. Two commercially available EVA alternatives (POE and TPO) have been selected. The material properties of single films as well as the electrical performance of test modules using these different encapsulants were investigated. The different films show comparable optical, thermal and thermo-mechanical properties, with slight differences in UV transparency and melting temperatures. Only shear viscosity values are higher for TPO than for POE and EVA, which requires adaption of the photovoltaic (PV) module lamination parameters. The test modules comprising the different encapsulation films show minor differences in the electrical performance after manufacturing; upon accelerated aging, no significant power loss is observed. But compared to TPO or POE, after 3000 h of damp heat exposure, test modules with EVA show the beginning of corrosion effects at the silver grid and above the ribbons. Based on the results, it can be stated that the new polyolefin encapsulation materials show great potential to be a valid replacement for EVA.

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Section: Module Testingmentioning

confidence: 99%

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confidence: 99%

Properties and degradation behaviour of polyolefin encapsulants for photovoltaic modules

Oreški

Omazic

Eder

et al. 2020

Progress in Photovoltaics

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“…The integrated area of the dark corrosion areas is directly proportional to an increase in the serial resistance R s and a loss in the P MPP. 9,63 …”

Section: Resultsmentioning

confidence: 99%

Quantifying the influence of encapsulant and backsheet composition on PV‐power and electrical degradation

Brune

Ortner

Eder

et al. 2023

Progress in Photovoltaics

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Although the technical and economic properties of the standard polymer photovoltaic (PV) materials (ethylene‐vinyl acetate (EVA) encapsulant and fluorine‐containing polyethylene terephthalate (PET) backsheet) meet the basic technical requirements, more sustainable polyolefin‐based encapsulants and backsheets have been developed. These new polyolefin materials have to prove their performance compared to the established standard materials in terms of the electrical performance of the modules and in terms of reliability. The long‐term stability of the new materials is tested and evaluated using accelerated aging tests and degradation modelling. Based on experimental results, the influence of the type of encapsulant and backsheet (i) on the electrical output power of PV test modules and (ii) on the aging‐related electrical and material degradation under accelerated stress tests was estimated using statistical modelling approaches. First results showing significant effects for encapsulant, backsheet and the combination of both on the initial power output are presented. In general, modules with polypropylene‐based backsheets have a higher initial power (PMPP) than those with PET‐based backsheets, with the combination of thermoplastic polyolefin (TPO) encapsulation material and polyolefin backsheet being superior to the other material combinations. A comparison of the material‐dependent degradation rates obtained from the mixed‐effects models clearly shows that the degradation rate upon damp heat exposure for modules with EVA is significantly larger than that using polyolefin encapsulants. The derived relations aim to provide valuable input for innovative material developments as well as predictive maintenance specifications.

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“…1) were used. While in 4 of the test procedures (so called Tropical 1 & 2, Arid 1 and Moderate 1) the application of stress was continuous, test "Alpine 1" comprised 3 consecutively applied stress procedures, which were repeated 5 times [24]. Beginning with 250 h of humidity and temperature (DH) storage, followed by 250 h temperature, humidity and irradiation aging and then by 1000 cycles of dynamic mechanical stress testing (DML).…”

Section: Experimental Approachmentioning

confidence: 99%

“…The UVF area ratio also significantly declined with aging duration. Increasing moisture penetration through the backsheet with exposure time was found to be responsible for (i) grid finger/busbar corrosion effects, reflected in changes in R S and P MPP and [24] (ii) changes in UVF area ratio [30] (Fig. 7).…”

Section: Accelerated Aging Tests: Temperature and Humidity Stress Imp...mentioning

confidence: 99%

Advanced UV-fluorescence image analysis for early detection of PV-power degradation

et al. 2023

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Reliability and durability of photovoltaic modules are a key factor for the development of emerging PV markets worldwide. Reliability is directly dependent on the chemical and physical stability of the polymeric encapsulation materials. One method capable of detecting ageing effects of the polymeric encapsulant directly on-site is UltraViolet Fluorescence (UVF) imaging. This work deals with advanced imaging analysis of UVF images and the subsequent correlation to electrical parameters of PV modules, which were exposed to climate-specific, long-term, accelerated aging procedures. For establishing a correlation, a so called UVF area ratio was established, resulting from the typical fluorescence patterns of the encapsulant material, which arise due to stress impact (e.g., water vapor ingress, elevated temperature, irradiation) and aging/degradation processes. Results of the data analysis show a clear correlation of the UVF area ratios and the electrical parameters with increasing aging time. In particular, the relationship between power and series resistance could be confirmed by extensive long-term test series with different climate-specific aging processes. Assuming the same type of polymeric encapsulation and backsheet and a comparable climate, determining the UVF area ratio can be used to estimate the service life and electrical power dissipation of each module installed in a PV array.

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Climate specific accelerated ageing tests

Cited by 4 publications

References 6 publications

Properties and degradation behaviour of polyolefin encapsulants for photovoltaic modules

Properties and degradation behaviour of polyolefin encapsulants for photovoltaic modules

Quantifying the influence of encapsulant and backsheet composition on PV‐power and electrical degradation

Advanced UV-fluorescence image analysis for early detection of PV-power degradation

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