Power generation has made intriguing progress recently. Photonic Power Business Unit of JDSU says it has achieved a world record: its 3 V and 5 V gallium arsenide photovoltaic power converter produces optical-to-electrical conversion efficiency >50%, near the maximum theoretical limit. Photonic power cost-effectively drives electronic devices operating in high-voltage, RF/EMI, and magnetic fields, where traditional copper options are complex or impractical. The improvement brings competitive advantages to industrial sensor, wireless communications, and medical applications, the company says. (www.sensorsmag.com/1006/SCnrg1~)
Roy Freeland, CEO of the U.K. company Perpetuum, says of his company's new vibration energy harvester, "No competitive offering has come close . . . in terms of the amount of data that can be sent or the conditions under which it will operate reliably."
The PMG7 microgenerator, available to OEMs and end users, converts kinetic energy from the vibration of equipment running at mains frequency (50 or 60 Hz) into electrical energy. It can generate up to 5 mW, which is enough to power a wireless transmitter sending 6 KB of data every few minutes, or small amounts of data, such as temperature readings, several times a second. It installs easily and can operate in most industrial environments and at minimal vibration levels (25 mg). (www.sensorsmag.com/1006/SCnrg2~)
Battery Developments
Several new battery technologies are in the R&D stage. Oak Ridge Micro-Energy, for instance, has developed a new rechargeable thin-film lithiumion battery that can operate at high temperatures. Based on a new anode-cathode combination, the company's prototypes were cycled at a record high of 170°C (338° F). Compare that to the conventional rechargeable lithiumion batteries that can cycle at about 60°C maximum. According to Mark Meriwether, president and CEO, this could open up new markets in areas such as sensors for downhole and other harsh environments, and semiconductor diagnostic wafers. (www.sensorsmag.com/1006/SCnrg3~)
 Oak Ridge Micro-Energy s rechargeable thin-film battery |
Rutgers University has granted mPhase Technologies the right to test its lithium-based alternative chemistries for a prototype nano-structured battery, which Rutgers says "promises to significantly change the storage battery industry."
In another announcement, mPhase reported that the microscopic structure designs of its prototype battery and magnetometer survived a high acceleration test at 12,000 g, conducted at Picatinny Arsenal, the Army's foremost munitions research facility. The test paves the way for developing small guided munitions. (www.sensorsmag.com/1006/SCnrg4~, www.sensorsmag.com/1006/SCnrg5~)
Military—And More
In many of military scenarios, battery maintenance is undesirable or impossible. So Neah Power Systems Inc. is working to extend its patented fuel-cell technology, based on porous silicon electrodes, to power sensors for military, portable electronics, and homeland security applications. "Most fuel cells require air to react with the methanol fuel to produce electricity," said chairman Dan Rosen, PhD. "Neah uses liquid electrolytes that enable them to be configured to either use air or run as a closed system in applications where you don't want your sensor and its fuel cell to be detected." (www.sensorsmag.com/1006/SCnrg6~)
And finally, MTI MicroFuel Cells Inc. (MTI Micro) says it has achieved an energy density of more than 1.3 Wh/cc of fuel on a 30 W laboratory test unit—which represents a >30% increase in fuel efficiency. For high-power applications, MTI Micro's direct methanol fuel cell (DMFC) system, Mobion-30, is being designed to produce up to 30 W of continuous power in a portable, lightweight, energy-rich power-pack, allowing deployed soldiers to use portable electronic devices for much longer periods of time. For low-power military applications, MTI Micro's Mobion-1 is designed to produce 1 W of continuous power. (www.sensorsmag.com/1006/SCnrg7~)
 Concept model of MTI Micro s Mobion-30 system |