Durable crystalline silicon photovoltaic modules based on breathable structure

• Published in: Japanese Journal of Applied Physics Vol. 60; no. 2; pp. 27001 - 27007
• Main Authors: Hara, Kohjiro, Chiba, Yasuo
• Format: Journal Article
• Language: English
• Published: Tokyo IOP Publishing 01.02.2021; Japanese Journal of Applied Physics
• Subjects: Acetic acid; Additives; Copolymers; Corrosion resistance; Crystal structure; Crystallinity; degradation; Durability; Encapsulation; Ethylene vinyl acetates; EVA encapsulant; Modules; Photovoltaic cells; photovoltaic module; Raman spectroscopy; Relative humidity; Silicon; silicon solar cell; Solar cells; Vinyl acetate
• ISSN: 0021-4922; 1347-4065
• DOI: 10.35848/1347-4065/abd447

The long-term durability of crystalline silicon (c-Si) photovoltaic (PV) modules was investigated by long-term damp-heat (DH) tests at 85 °C with 85% relative humidity. Breathable module structure using front or rear materials with low-barrier properties markedly improved the long-term DH resistance of c-Si PV modules. No corrosion of finger electrodes on c-Si solar cells occurred by diffusion of acetic acid, which was formed from an encapsulant of a random copolymer of ethylene and vinyl acetate (EVA) towards the outside of the modules by the breathable structure. Raman spectroscopy data indicated that degradation of the EVA encapsulants including additives (e.g. UV absorber) were suppressed by the usage of a breathable front film compared to a front cover glass used for the conventional modules. The breathable modules based on low-barrier components would improve the long-term photochemical and chemical durability of c-Si PV modules further to achieve 40 year operation.