Mini-Generator Could Power Smartphones for Days
CREDIT: Justin Knight
The frustratingly short battery life of smartphones and laptops could soon give way to new, button-size generators capable of powering our electronics for days. The MIT-made devices use the same butane fuel found in cigarette lighters, but convert the fuel's heat into precisely tuned light waves so that solar cells can generate electricity with maximum efficiency.
Each generator has a fuel-to-electricity conversion efficiency three times greater than a lithium-ion battery of similar size and weight found in today's gadgets. The MIT team believes that it can eventually triple the amount of energy packed into the device, and perhaps pave the way for a new generation of tiny devices that can power sensors, smartphones and medical monitors .
"At that point, our TPV (thermophotovoltaics) generator could power your smartphone for a whole week without being recharged," said Ivan Celanovic, a research engineer in MIT's Institute for Soldier Nanotechnologies.
Miniature power supplies may also lighten the load for U.S. soldiers who must carry hundreds of pounds of batteries on patrols. That would also reduce the U.S. military's logistics chain of airplanes and truck convoys , which risk enemy fire and roadside bombs to deliver gadgets to the frontlines.
"There are a lot of lives at stake, so if you can make the power sources more efficient, it could be a great benefit," said Mike Waits, an electronics engineer at the Army Research Laboratory in Adelphi, Md., who was not involved in this work.
The generator's secret comes from a specially engineered material that has billions of microscopic pits on its surface. Such detail ensures that the material only emits heat at the wavelengths that photovoltaic cells can absorb, and avoids wasting energy.
That heat-harnessing approach has also allowed MIT engineers to create a nuclear battery that can create electricity for 30 years without refueling or maintenance. Such a power source could prove ideal for robotic spacecraft heading away from the sun on deep space missions to other planets or their moons.
"Being able to convert heat from various sources into electricity without moving parts would bring huge benefits; especially if we could do it efficiently, relatively inexpensively and on a small scale," Celanovic said.