A solar cell that tracks the sun’s movement across the sky can generate 40% more electricity than a stationary panel. But tracking devices add complexity and cost. They also are subject to malfunction due to ice, snow, or high winds.
Researchers at the University of Michigan, led by Max Shtein and Stephen Forrest, both professors of materials science and engineering, say they have devised a new solar tracking technology that follows the sun without moving an entire solar panel. They cut solar cells into specific designs using kirigami, a variation of origami which entails cutting in addition to folding, reports CleanTechnica.
Making a specific kirigami cut creates strips in a solar cell. By pulling the two ends in opposite directions, the strips can make the solar cells tilt and assume a desired angle. Done correctly, the structure changes shape in a way that prevents the individual strips from casting shadows on each other and the “waviness” of the new form does not detract from solar performance.
The kirigami approach makes it possible to generate more electricity while using the same amount of semiconducting material and is nearly as effective as conventional tracking systems, says Shtein. Most of those systems are cumbersome and costly. Not only that, they don’t work well on most pitched rooftop systems, which account for the majority of rooftop solar installations.
The University of Michigan system uses flexible solar cells made of gallium arsenide. The research is only at the “proof of concept” phase and will take a lot more work before the system is suitable for commercial applications. The researchers need to devise a system for encasing the structures to protect them against the weather and provide mechanical support. Then they will need small electric motors to pull the cells apart at specific times during the day.
“It doesn’t take much force at all,” says Shtein. Although the approach is best suited for thin, flexible materials; in principle, it could work with “almost any kind of solar cell,” he says.