New technologies for flexible solar power
Aesthetics seems to be one of the driving forces for widespread deployment of building-integrated photovoltaics (PVs). This tantalising sustainable energy concept provides opportunities for generating electricity and replacing conventional construction materials. The demand for diverse shapes, sizes, colours and transparency levels is high; however, the products are lacking. Current PV modules are based on fixed shapes and electric output. Although this may be great for large solar plants, it is costly and inefficient for building designs or other solar-powered products. The EU-funded project SOLAR DESIGN (On-the-fly alterable thin-film solar modules for design driven applications) addressed the need for customised PV cells that are flexible and easy to integrate through the development of novel solar cell materials and manufacturing processes. The project developed new scribing and printing technologies that enable monolithically interconnected flexible solar modules. The new monolithic interconnection processes simplify the production of thin-film modules. They allow not only adjustment of the module's electrical properties on the fly but also the production of fully customised PV modules with respect to size, shape and voltage. In particular, the team implemented this process on the solar foil of width 300 mm, allowing curved solar cells and interconnection patterns of a radius of at least 10 mm. Project members replaced the use of cadmium in sulphide buffer layers with other materials such as stainless steel and polyimide, which are abundant and not toxic. They also delivered thin, flexible and transparent encapsulants for protecting the most sensitive portions of PV modules. Choosing the right material not only increases module durability, but also enhances light entrapment and thus module efficiency. Except for buildings, thin-film, lightweight and flexible high-performance solar modules are attractive for numerous applications such as electronic devices and electric vehicles. SOLAR DESIGN is expected to accelerate widespread uptake of solar-powered products that will be developed and showcased all over Europe.
Keywords
Thin-film solar cell, CIGS, building-integrated photovoltaics, SOLAR DESIGN, solar modules