As the size of specialized electronic components continues to shrink, the absence of an equally shrinkable power source has been an Achilles heel.
What's the value of having a device smaller than a postage stamp if it has to be strapped to a battery many times its size?A team of Brigham Young University engineers and Orem-based Bipolar Technologies have refined microbattery technology to produce a battery so small it can best be viewed under a microscope.
Potential uses for the device leave development team leader Linton Salmon's head swimming as he considers the possibilities: implantable insulin monitors; tiny transmitters on box labels that let a computer track or inventory them; self-powered smart cards.
The batteries can also be recharged using solar cells, which could make a remote sensing device self-recharging, or by exposing them to radio frequency energy, which could make a pacemaker rechargeable without the battery having to be surgically replaced.
Don't expect to see micro-battery-powered flashlights or toys on the market. Their development follows a need for power in more specialized devices. "Wherever you need an autonomous, low-power power source, that's where these microbatteries really shine," said Salmon, BYU's associate dean of engineering and technology. The development team was also led by John Harb, associate professor of chemical engineering.
A single microbattery measures one-tenth of a millimeter. Most uses would incorporate a group of the tiny batteries in a series or parallel configuration that would still be small enough to package with a microchip.
"We build microbatteries using the same processes employed to build computer chips - intricate patterning with extremely small dimensions and extremely pure materials. We hope to achieve the same kind of performance advances in the micropower field that have occurred in the computer industry," Salmon said.
Salmon, who received a doctorate in applied physics from Cornell University, presented the results of his team's research at the Solid-State and Actuator Workshop, a premier industry forum, last week.
Robert Huber, a professor of electrical engineering at the University of Utah and a member of the workshop's program committee, says Salmon's paper was selected because it represents new and innovative work of high quality that could potentially impact the field.
"What Salmon's research does is allow producers to simplify the circuitry in heretofore complex systems," Huber said. Engineers can now design the power source directly into micro-elec-tromechanical systems - tiny devices also known as MEMS.
Salmon supervised MEMS research for the National Science Foundation in the early 1990s. He noticed fellow engineers were developing tiny, intricate systems that could be very useful except for one problem: "Many of them were powered by a D-cell battery," Salmon remembers."There's no point in building a MEMS product if there is no energy source correspondingly small enough to power it."
He and his colleagues set out to conquer the power-source challenge when he left the government job for his BYU faculty post.
Bipolar Technologies has applied for patents on the microbattery and will be pitching the new device to potential users. "Initially we will target the markets that can use remote or autonomous sensors, such as the automotive and medical industries," said Bipolar Technologies President Rodney LaFollette.
Protracted FDA approval processes for medical devices means non-medical uses for microbatteries will likely develop first, Salmon said.