At the Semicon West convention held earlier this month, several representatives from Darnell Group held a panel discussion on the energy harvesting and its forthcoming mass appeal. Speakers included Jeff Shepard, president of Darnell, Jerry ruddle, executive vice president with Advanced Cerametrics and Solicore’s vice president, Jarreth Solomon.
Shepard opened by discussing the different market strategies needed in order for energy harvesting devices and micro fuel cells to take off and hold in the market. Shepard focused on the lack of success micro fuel cells have faced—blaming its troubles on targeting inappropriate markets like the cell phones and laptop industries.
"Both micro fuel cells and energy harvesting devices can find markets when they are used to replaced large numbers of batteries," Shepard observed. "For energy harvesting devices, that means applications such as wireless sensor networks with large numbers of nodes. For micro fuel cells, it is auxiliary or remote power applications where the need is for hundreds of watt-hours of continuous operation, and the fuel cell replaces many individual batteries; not small portable devices such as handsets or laptops."
Ruddle spoke on the ability of Advanced Cerametrics’ flexible piezoelectric fiber composite transducers to harvest mechanical energy and convert it into electrical energy. He showed the ability of piezoelectric fiber composites to produce 500 V (at resonance frequency of 35 Hz, that can charge a 400 µF capacitor to 50 V in less than 4 seconds. He claimed that materials have been configured to produce 145-mW output.
Moving past piezoelectric technology, Ruddle focused on Advanced Cerametrics’ Viscose Suspension Spinning Process (VSSP). This technique meshes two old technologies: fiber spinning and ceramics with today’s techniques. According to Ruddle, VSSP creates lighter, stronger, more flexible, and less expensive ceramics compared to traditional methods.
Presenting the latest developments from Solicore, Solomon spoke about the Flexion lion of lithium-polymer batteries. These are solid state, polyimide-based batteries claimed to delive up to 50 mA and can withstand 135°C. The unit has a shelf life of three years and is .45-mm thick. Its primary use is in smart cards and can perform tens-of-thousands of transactions, according to Solicore.