Sir Isaac Newton 2.0: A body in motion might one day become a power pack

Jan 18, 2017

Electricity is an abundant power source.  But harnessing it for everyday use is sometimes tricky. 

But what if you could charge your phone with your own body?

 

That question is being studied at Michigan State University with a device that uses nanotechnology.

 


How often have you awakened early in the morning, eyes half-opened, and think, “I just don’t have the energy to get out of bed.”  We’ve all been there.

But what if the physical motion of getting out of bed actually created the energy you need to face the day? Even if it’s only just enough to turn on the coffee?

Every time we move, our bodies generate mechanical energy...and that force can be converted into electricity.

Dr. Nelson Sepulveda is an associate professor of electrical and computer engineering.  He’s leading a team that’s constructed a small, thin sheet of silicone.  It’s called the “FENG,” short for ferroelectric nanogenerator.

“And whenever it’s pressed, whenever it experiences some mechanical deflection, it generates some electricity,” Sepulveda explains.  “It’s flexible, it generates a substantial amount of electric power per unit (of) stress, and it increases the output by just folding (it).”

When the FENG is compressed, it gets stronger and can create up to four times its original power capacity.  The secret lies in layers.

Remember the wake-up analogy?  Think about your sheets and blankets.  There’s air pockets between each layer.  But they’re not exactly empty.  

“Imagine that within each bed sheet layer, you have really, really tiny particles that are charged,” Sepulveda says.  “They have a positive or negative charge.”

Those ions don’t like being pushed around.  So, if you press your hand on the stack of blankets, they’re going to fight back.  Quietly.

“And the way they do that is by creating an electric field that generates a force that opposes the mechanical deflection,” Sepulveda adds.  “That electric field is what generates the electric power that we’re extracting from the device.”

Doctoral student Wei Li demonstrates this concept.  Donning a latex glove, he presses the heel of his hand onto the nanogenerator, which is connected to an LED circuit board via two small wires.

No battery.  

It takes a few tries, but a series of green and blue lights start to blink with each thrust of Li’s hand.

Li was instrumental in the FENG’s creation.  He says even as electronic devices become smaller and more portable, they still only hold a very limited charge.

“So I was thinking about an idea.  People everyday...mechanical energy is generated from human beings, yourself.  If we can use this energy to charge a wearable or portable device, we can solve the problem of the shortage of the battery.”

Once its fully developed, the FENG might one day charge your smartphone for an entire week, not just a few hours.  

But that will take some time.  There’s still some lab work ahead.

“We need to understand all of the parameters that actually play a role in the performance of the device,” says Dr. Sepulveda.  “We once we do that, I think we’ll be in business.”

And when might that business arrive?  Sepulveda predicts it will take about five years for FENG to make it out of his lab and onto the market.