Maximizing Energy from Solar Panels on Slanted Roofs with kirigami shapechanging solar cells

Researchers have shown a new way to help solar cells track the sun as it moves across the sky, which could boost a panel’s energy generation by 40 percent.

Most of the solar panels in the world sit on rooftops at a fixed angle, so they miss out on capturing energy during parts of every day. Now researchers have shown that by cutting solar cells into specific designs using kirigami, a variation of origami which entails cutting in addition to folding, they can allow the cells to track the sun’s angle without having to tilt the whole panel. This could have a substantial payoff: solar panels with tracking mechanisms can generate 20 to 40 percent more energy per year than those without trackers

As shown in the video here, applying a specific kirigami cut creates strips in a solar cell. Pulling the two ends in opposite directions causes the strips to tilt and assume a desired angle. Crucially, the structure morphs in such a way that prevents the individual strips from casting shadows on the others, and the “waviness” of the new form does not detract from performance, says Max Shtein, a professor of materials science and engineering at the University of Michigan. Shtein led the research along with Stephen Forrest, also a professor of materials science and engineering at the University of Michigan.

Kirigami structures combined with thin-film active materials may be used as a simple, low-cost, lightweight and low-profile method to track solar position, thereby maximizing solar power generation. These systems provide benefits over conventional mechanisms, where additional heavy, bulky components and structural supports are often required to synchronize tracking between panels and accommodate forces due to wind loading. By eliminating the need for such components, kirigami serves to decrease installation costs and expose new markets for solar tracking, including widespread rooftop, mobile and spaceborne installations. Kirigami-enabled systems are also cost-effective and scalable in both fabrication and materials, and similar design rules may be extended for use in a wide range of optical and mechanical applications, including phased array radar and optical beam steering.