Inkapsling av solceller för att maximera effektintaget i en solbil
Examensarbete på kandidatnivå
The purpose of this study is to investigate suitable materials for encapsulating solar cells that will power an electric car. The encapsulation shall provide a protective layer against mechanical stresses and weatherability whilst reducing the efficiency as little as possible. Important characteristics that have been identified for the encapsulation material is high transmission, specific stiffness and strength including high operating temperatures, melting temperature and heat capacity. In the initial part of the study, a material database was used to sift materials that had potential. Followed by eliminating materials that had low transmission capabilities. Samples of the last remaining materials were then collected for tests to be carried out. Two types of experiments were carried out; 1) FTIR measurements to determine the transmission of the materials and 2) measurements on the solar cells inside a weatherometer to determine the materials weather resistance and the impact on the efficiency of solar cells. The weatherometer was set to simulate high temperature and UV-radiation. As for the mechanical properties, data from the materials datasheets was used to evaluate their performance. Measurements inside the weatherometer showed that the efficiency of the solar cells decreased when encapsulated with the respective material as follows: 2.9 % for polyethylene defthalate (PEN), 6.7 % for polymethyl methacrylate (PMMA), 4.6 % for polyethylene terephthalate (PET) and 3.8 % for fluorinated ethylenepropene (FEP). Some of the materials were deformed during the exposure inside the weatherometer. The material that had the least reduction in efficiency was PEN. The material had good mechanical and thermal properties and remained adhered to the solar cell with the chosen method of application. Thus, PEN was the material with the best overall performance and is therefore recommended as an encapsulant with the selected method of application.
Solar cells, Encapsulation, Efficiency, Polymers