Influences of Different Lamination Conditions on the Reliability of Encapsulation of PV Modules

• DOI: 10.4229/eupvsec20142014-5dv.3.43
• Publication Date: 2014-11-07
• Authors: Ralph Gottschalg; Thomas R. Betts; Daniel Montiel-Ch...; Jiang Zhu; Dan Wu
• Keywords: Encapsulation

29th European Photovoltaic Solar Energy Conference and Exhibition; 3415-3420<br/>A high quality encapsulation is required for photovoltaic (PV) modules to ensure the long-term performance and reliability. For crystalline silicon PV modules, the encapsulation is normally carried out using a flatbed laminator where temperature, time, pressure and cooling rate are able to be controlled. These parameters will influence the properties of encapsulation materials which are expected to be linked with their weather resistivity and thus the durability of PV modules. This paper investigates the influences of three different lamination temperatures of 125oC, 135oC and 145oC on the encapsulation durability of PV modules from the viewpoint of adhesion strength, the cross-linking states of Ethylene Vinyl Acetate (EVA), chemical stability and optical changes. Results show that laminates cured at 125oC is less stable than that cured at higher temperature with problems like weak adhesion between EVA and backsheet, bad crosslinking, unstable chemical properties and obvious optical yellowing and haze. Samples cured at 135oC and 145oC are comparable. Curing temperature of 145oC ensures high crosslinking which in turn reduces the mobility of EVA molecules which compensates the advantages of higher temperature on material diffusion. Higher temperature also increases material stiffness which although improves EVA creep resistance, increases material brittleness. 135oC has a good curing state but is less chemical and optical stable than that cured at 145oC.<br/>