Technology and Performance of Bifacial Half-Cell Modules for desert climates

In this research plan, we aim at adapting Photovoltaic (PV) module design and material to ensure excellent performance and reliability of PV modules in Qatar climatic conditions. A bifacial half-cell PV module concept is proposed as a candidate for a sunny, dust and hot desert climates. Half-cell technology has the potential to reduce the series resistance and to improve the energy yield. The bifacial concept will be combined in order to utilize the diffuse and reflected solar irradiance. Anti-reflective and Anti-Soiling Coatings will be used to improve the light transmission and minimize soiling, respectively. In addition, the glass-glass module layout with an ionomer encapsulant material will be utilized to resist high humidity and UV irradiance conditions. The data obtained from real outdoor testing conditions serves as a design guideline to develop PV module performance and reliability. The obtained knowledge will be the basis for the development of new testing protocols for desert PV modules with enhanced module reliability and later transferred to international standards and certification of desert modules. The scope of work includes technology development, indoor and outdoor testing of PV modules and thermo-mechanical modelling. In summary, the following tasks will be carried out: • Fabrication of bifacial half-cell PV mini-modules with: o An advanced cell separation process for achieving bifacial half-cells o New materials and adapted technologies for desert modules (e.g. Different encapsulant materials) o Glass-Anti-Reflective Coating (ARC) and Anti-Soiling Coating (ASC) • Material and module characterization and indoor testing: o Adapted characterization techniques for bifacial half-cells and mini-modules for material screening o Characterization of encapsulant material o Defect analysis of field returns: material degradation (e.g. UV, T, LID) o Dedicated test standards/bench mark for desert PV modules and systems, such as, extended thermal cycling, damp heat and UV irradiance testing conditions • Outdoor testing o Monitoring and assessment of energy yield o Perform visual inspection, spectral imaging, thermal imaging, PID and Electroluminescence (EL) imaging to identify the most common failure mechanisms that affect module performance and reliability o PV soiling characteristics and contact angle measurements for different glass/ARCs • Thermo-mechanical and energy yield modelling o Development of a thermo-mechanical model for module components (cell interconnection)  prediction of module failure modes due to the thermal cycling o Development of a yield model  Prediction of energy yield Expected outcomes • Design a reliable PV module with high energy yield suited for desert climates • Benchmark gold standard for testing desert PV modules • Energy yield prediction for improved bankability analysis Expected impact of this project • The proposed research plan is expected to improve the fabrication of bifacial half-cell module and develop a low-cost, high energy yield and reliable PV module concept that suits desert climate conditions • A prototype module assembly line will be developed to accelerate the commercialization of bifacial half-cell PV modules • The project open new opportunities for further development of the technology and materials for desert-specific bifacial half-cell PV module in this constellation also after finishing the project (networking) • Using the unique indoor and outdoor capabilities at QEERI-HBKU, the project will create opportunities to have an accredit lab in Qatar for testing and certifications of desert-modules (since so far there are no specific tests within the International Electrotechnical Committee (IEC) for desert PV modules)

Hamad Bin Khalifa University (HBKU)