A hot idea for insulating tiny batteries

Jan 10, 2007

Engineering physics researchers are devising a unique "blanket" that will enable them to squeeze as much electricity as possible from nuclear-powered batteries the size of a grain of coarse salt.

Such batteries, which exploit the natural decay of radioisotopes to generate electricity, could provide virtually indefinite power for micro-technologies like fly-sized robots for military applications or sensors that monitor a building's health.

Other technologies such as fuel cells, chemical batteries or turbine generators also might work in micro-scale applications, says Professor James Blanchard. "But all of them are short-lived," he says. "They either need to be recharged or refueled. Our niche is things that need to be placed and ignored, and just keep running for years."

Nuclear microbatteries convert heat or energy to electricity more efficiently when they are hot, so it makes sense to insulate them, says Blanchard. "The better the insulation, the hotter the source gets, so the more efficient the battery can be," he says.

However, insulating a millimeter-square battery in a way that minimizes heat loss is no easy task. Multifoil insulation is an effective macro-level insulator that combines several thin layers of foil each separated by a vacuum. "They work because they're radiating heat from one layer to another, as opposed to conducting heat through a solid," says Blanchard.

For the microscale, however, multifoil insulation is far too thick.

So, capitalizing on the layered concept, which reduces heat radiation for a fixed temperature drop, Blanchard and graduate student Rui Yao decided to sandwich semicircular silicon oxide pillars-poor conductors-between very thin silicon sheets.

"You want as little conduction through these pillars as possible," says Blanchard.

They developed elaborate computer models to study the heat radiation and conduction of their microscale insulaton. And, using Wisconsin Center for Applied Microelectronics clean room facilities, Yao constructed silicon prototypes.

He now is experimentally verifying what his computer models suggest-that heat is radiating through the silicon layers without much heat loss. "The prototypes he built are a little thicker than the ones we ultimately want to get, but they're consistent with his models," says Blanchard.

Funded by a three-year, $300,000 Department of Energy grant and inspired by an earlier collaboration with Sandia National Laboratory researchers, Blanchard and Yao are still testing and refining the insulation. Implementation for this promising technology, they say, is a couple of years down the road.

"It looks like we'll have an effective insulator that's better than any solid-and better, even, than some of the multi-foil insulations that you can buy commercially," says Blanchard.

Source: University of Wisconsin

Explore further: New filter could advance terahertz data transmission

add to favorites email to friend print save as pdf

Related Stories

Several "new" craters found in Siberia

11 minutes ago

At least seven newly created mysterious craters have now been officially discovered in Siberia, though satellite imagery suggests there may be as many as 20. The discovery of the first three last year caused a small media stor ...

Canada looks east-west to ship oil after Keystone veto

5 hours ago

After US President Barack Obama vetoed a bill to expedite construction of the Keystone XL pipeline Tuesday, petroleum producers are expected to turn to Canadian routes to ship oil internationally, but hurdles ...

Internet access limited in developing world

5 hours ago

Most people in the developing world do not use the Internet, with access limited by high costs, poor availability and a lack of relevant content, a Facebook report said Tuesday.

Manhattan Project physicist Ralph Nobles dies at 94

5 hours ago

(AP)—Ralph Nobles, a nuclear physicist who worked on the Manhattan Project and later led efforts to save thousands of acres of San Francisco Bay wetlands from development, died following complications of pneumonia, according ...

In Japan, robot dogs are for life - and death

6 hours ago

Incense smoke wafts through the cold air of the centuries-old Buddhist temple as a priest chants a sutra, praying for the peaceful transition of the souls of the departed.

Recommended for you

New filter could advance terahertz data transmission

10 hours ago

University of Utah engineers have discovered a new approach for designing filters capable of separating different frequencies in the terahertz spectrum, the next generation of communications bandwidth that ...

The super-resolution revolution

10 hours ago

Cambridge scientists are part of a resolution revolution. Building powerful instruments that shatter the physical limits of optical microscopy, they are beginning to watch molecular processes as they happen, ...

A new X-ray microscope for nanoscale imaging

13 hours ago

Delivering the capability to image nanostructures and chemical reactions down to nanometer resolution requires a new class of x-ray microscope that can perform precision microscopy experiments using ultra-bright ...

Top-precision optical atomic clock starts ticking

Feb 26, 2015

A state-of-the-art optical atomic clock, collaboratively developed by scientists from the University of Warsaw, Jagiellonian University, and Nicolaus Copernicus University, is now "ticking away" at the National ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.