Energy harvesting (EH), sometimes referred to as energy scavenging, has gained tremendous attention as a means to lessen or eliminate the need for battery power. Novel approaches have been available to generate power by utilizing energy from human and environmental sources. Given battery limitations wider adoption of EH is coming but requires a clever combination of design skills. A multi-discipline approach that leverages knowledge in several fields of engineering is required, including electrical, mechanical, material, and process.
EH itself is not new. Consider hand cranked radios, flashlights powered by shaking, windmill farms, and solar energy. What is new is the application of EH for ultra low power embedded electronics. The convergence of high charge piezoelectric ceramics and fiber composite process technology has enabled the application of self-powered systems for a wide array of electronic systems.
Convergence of technologies: Ultra low power electronics
The science of piezoelectric devices is fairly well understood in the engineering world, but their application remains a nascent field rich with possibilities. The emergence of piezoelectric ceramic fiber “super transducers” that offer increasing deliverable power, combined with electronic components that measure performance in nanowatts, is opening a wide range of new product and services. The need for Extreme Life Span Power Supplies (ELSPS) for numerous electronics systems and devices is fueling extensive research, development, and growth.
Piezoelectric ceramic fibers, given their unique properties, offer the greatest potential for enabling the wide-scale deployment of self-powered systems.
Convergence of technologies: Piezoelectric ceramic fibers from VSSP
Conventional piezoelectric ceramic materials are rigid, heavy, and produced in block form. A low-cost technology termed the Viscose Suspension Spinning Process (VSSP) can produce fibers range in diameter from 10 microns (1/50 of a human hair) to 250 microns. When formed into user defined (shaped) composites, the ceramic fibers possess all the desirable properties of ceramics (electrical, thermal, chemical) but eliminate the detrimental characteristics (brittleness, weight). The VSSP generates fibers with 20-30% more efficient energy conversion than traditional bulk ceramics. To put this into perspective, mechanical to electrical transduction efficiency can reach 70% compared with the 16-18% common to solar energy harvesting. And vibrations can be harvested 24 hours per day!