A newly-developed fabric can be used to continuously power electrical components by weaving a piezoelectric yarn.
We have previously seen materials that provide power in unusual ways, including a fabric that can harvest energy from wind and a fuel cell powered by sweat. Now, researchers at Chalmers University of Technology, in Sweden, have developed a woven fabric that generates electricity when it is stretched or exposed to pressure. Chalmers researchers, Anja Lund and Christian Müller, created the material by weaving a piezoelectric yarn together with an electrically conducting yarn. The resulting fabric can generate enough energy to light an LED. Additionally, it can also send wireless signals or power a pocket calculator or digital watch.
The yarn is made up of twenty-four fibres, each as thin as a strand of hair. The piezoelectric strands generate electricity when they are stretched, and the conducting strands transport the current. Lund explains, “The piezoelectric fibres consist of a piezoelectric shell around an electrically conducting core. The piezoelectric yarn in combination with a commercial conducting yarn constitute an electric circuit connected in series”. The new material is soft and flexible, and becomes more efficient when moist or wet.
The researchers demonstrated their results by incorporating a piece of the material into the strap of a shoulder bag. When the bag is loaded with books, it bounces up and down, generating a current. Lund suggests that making an entire bag from the textile would generate enough energy to transmit wireless signals. Previous work has already led to the ability to generate electric signals using pressure. However, being able to use piezoelectric fibres to continuously power electronic components is unique. The researchers believe that the technology is ready for larger scale production, with the cost of production being comparable with that of Gore-Tex. They have already collaborated with the Swedish School of Textiles to demonstrate that the yarn can be woven in industrial looms. What uses might there be for a yarn that can generate electricity?