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1609wheeler-thesis-final.pdf (14.71 MB)

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Lifetime and Degradation Science of Polymeric Encapsulant in Photovoltaic Systems: Investigating the Role of Ethylene Vinyl Acetate in Photovoltaic Module Performance Loss with Semi-gSEM Analytics

Wheeler, Nicholas Robert
http://rave.ohiolink.edu/etdc/view?acc_num=case1473440287427776

Abstract Details

2017, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science and Engineering.
The lifetime performance and degradation behavior of photovoltaic (PV) modules is of the utmost importance for the success and growth of solar energy as a major resource for fulfilling growing worldwide energy needs. While PV reliability has been a concern for some time, existing qualification testing methods do not reflect a cohesive picture of the science behind module degradation, and are not capable of accurately predicting module lifetime performance. Towards these goals, a statistical methodology, semi-gSEM, was developed and applied to investigate the response of full sized PV modules to accelerated stress conditions. The results of this initial study indicated that a correlation exists between system level power loss and the buildup of acetic acid resulting from the hydrolytic degradation of ethylene-vinyl acetate (EVA) polymer encapsulant. To further explore this proposed mechanistic pathway, a study was designed and conducted to characterize the degradation of mini-module samples under damp heat accelerated stress conditions. Mini-module samples featured two construction geometries that differed in the thicknesses of screen-printed silver conductive lines (SP-Ag) to assess the impact of gridline size on damp heat induced degradation. Samples were measured non-destructively at many points along their degradation pathway, using techniques that gathered both chemical and electrical information. The semi-gSEM analytical method was applied to this dataset to highlight degradation pathways and mechanisms observed in the experimental results. An EVA encapsulant spectroscopic degradation feature was found to be statistically related to quantified degradation features of simultaneously measured EL images. In turn, the EL image degradation was found to be statistically related to I-V curve parameters describing system level power loss. The degradation pathway observed was attributed to EVA encapsulant degradation leading to metallization corrosion and ultimately system level power loss in the PV mini-module samples. Mini-module samples with thinner SP-Ag conductive lines were observed to be more severely damaged by the metallization corrosion process. This represents a valuable step in exploring the often misunderstood role of EVA degradation in PV module performance loss under damp heat conditions, and demonstrates novel methodologies for building a more integrated picture of PV module degradation as a whole.
Roger French (Advisor)
Michael Hore (Committee Member)
Timothy Peshek (Committee Member)
Laura Bruckman (Committee Member)
Ozan Akkus (Committee Member)
106 p.
Materials Science; Plastics; Polymers
Photovoltaics, PV, Lifetime and Degradation Science, EVA, semi-gSEM, Statistics, Data Science, Polymer Degradation, Polymer Science, Polymer Engineering, Materials Science

Recommended Citations

Citations

  • Wheeler, N. R. (2017). Lifetime and Degradation Science of Polymeric Encapsulant in Photovoltaic Systems: Investigating the Role of Ethylene Vinyl Acetate in Photovoltaic Module Performance Loss with Semi-gSEM Analytics [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1473440287427776

    APA Style (7th edition)

  • Wheeler, Nicholas. Lifetime and Degradation Science of Polymeric Encapsulant in Photovoltaic Systems: Investigating the Role of Ethylene Vinyl Acetate in Photovoltaic Module Performance Loss with Semi-gSEM Analytics. 2017. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1473440287427776.

    MLA Style (8th edition)

  • Wheeler, Nicholas. "Lifetime and Degradation Science of Polymeric Encapsulant in Photovoltaic Systems: Investigating the Role of Ethylene Vinyl Acetate in Photovoltaic Module Performance Loss with Semi-gSEM Analytics." Doctoral dissertation, Case Western Reserve University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1473440287427776

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.