Re-Imagining Energy: Storing Energy

As the land-grant university for the energy-rich state of Pennsylvania, it isn’t surprising that Penn State counts among its core strengths a broad and deep expertise in energy-related research. Today, in areas from materials science to policy, from environmental chemistry to architectural and electrical engineering, the range and quality of our research make Penn State a world leader in energy research.

We've produced a package of five stories that capture just a sliver of that expertise, briefly sampling some of the more innovative ideas of Penn State researchers working together to solve key questions of making and using energy.

Please visit our other posts on:

Generating energy—tapping natural processes to power our future

Catching carbon—new technology to capture CO2 before it gets into the atmosphere and either sequester it or use it to create new products

The built environment—how new inventions and design principles are making our buildings and appliances more energy-efficient

Pulling it all together—integrating new sources of energy with the traditional electric grid to provide reliable, sustainable power for homes and businesses

And for an inside look at how Penn State students are making a mark in the field of wind energy, see A Shift in the Wind.

“The beauty of batteries is you don’t have to think about them,” says Chris Rahn, a mechanical engineer whose research focuses on battery systems. Rahn drives an electric car to work and has solar panels on his home. “When I make my daily commute, I’m not burning any fossil fuels,” he says. “It’s amazing that you can have the sun shine on a panel on your house, charge the battery in your car with that solar energy, and then drive. It’s revolutionary.”

The past few years have brought a surge in battery technology. Here’s a sampling of how Penn State researchers are changing the battery landscape.

TIME TO RECHARGE

Lithium-ion batteries came on the scene in the late 1990s and soon became ubiquitous. Used to power devices such as laptops and smartphones, rechargeable lithium-ion batteries are popular because they’re lightweight, store a lot of energy, and can run for a long time. 

Despite the advantages of lithium-ion batteries, they don’t handle high temperatures well and occasionally burst into flames. “Safety is an issue whenever you have high-energy-density batteries,” explains engineer Chao-Yang Wang. “When a lot of energy in a small volume is released all at once, that’s a problem.” Yang’s lab works at the materials and cell level on the thermal management of batteries, designing less flammable materials. 

They recently received a $1 million grant from the U.S. Department of Energy to work on fast charging of electric car batteries and have developed a technology that allows car batteries to be charged within ten minutes. “You can then drive 250 miles on that charge,” he says. “Yes, that’s a limited range, but you can charge up again in the few minutes it takes to get a cup of coffee and check your messages.” Because it can be charged so quickly, it can be smaller than electric vehicle batteries currently in use—which makes it safer as well.

—Krista Weidner 

START ME UP

Wang and his colleagues have also developed a battery that won’t freeze in cold climates, a feature that could make the use of electric vehicles more widespread. Like conventional car batteries, current electric vehicle batteries work poorly in extreme cold. They take hours to charge, and even when fully charged, they may not be able to start the car because the movement of ions within the battery slows down significantly. 

The new all-climate car battery warms itself up, allowing it to charge fast or promptly start the car no matter the outside temperature. The remote key used to unlock the car doors “could also trigger the pre-heat switch,” says Wang, “and by the time the person sits on the driver’s seat, some seconds later, the battery has already warmed up and is ready to drive away”—even at ambient temperatures as low as minus 45 degrees Fahrenheit. 

—Krista Weidner

BETTER POLYMERS FOR BIGGER BATTERIES

Materials scientist Mike Hickner and his group work at a molecular level to make better large-scale batteries—those that power buildings, water treatment plants, and neighborhoods. 

In these flow batteries, a polymer membrane separates the anode and the cathode to allow ions to flow back and forth during charging and discharging, while ensuring the active redox molecules are not lost. Hickner uses polymer chemistry to modify the membrane’s transport properties, designing next-generation membranes in iterative testing with cell engineers. “We like to send samples out and have the battery engineers break them and help us improve our materials,” says Hickner. “This back-and-forth is a real competitive advantage for my group.”

Hickner and his group are also beginning to explore using 3D printing technology to create battery membranes. “3D printing allows us to make unusual shapes and make them quickly,” he says. “In my lab, we have people who know about molecules, and we have students interested in 3D printing, so we can integrate ideas from different disciplines.”

—Krista Weidner

INTO THE FUTURE

These latest advances are just the beginning of smart batteries,” Rahn says. “On the horizon is a whole new world of batteries that can live a long time, operate at all temperatures, and charge quickly. When it comes to car batteries, this will eliminate what we call ‘range anxiety’—fear that your car battery will run out before you can recharge. In fact, one day we might see drivers of gasoline-powered cars having range anxiety because gas stations will be disappearing.”

Yang agrees that battery technology will change the future. “Before long, and it’s already starting, we’ll have battery-powered robots working diligently, cleaning the house, doing laundry, cooking for us, transporting people.”­­

—Krista Weidner

THE BEST CENTER: FROM MATERIALS TO SYSTEMS

The multidisciplinary Battery Energy Storage Technology (BEST) Center brings together researchers from across the University who look at battery technology at all levels, from materials to power cells to systems, and collaborate on new approaches.

“The work we do at BEST leads to real-world impact,” Rahn says. He and Chao-Yang Wang direct the BEST Center. “If you’re a materials person and demonstrate something on a small scale, you always wonder, can we scale up? Can we make this into a commercial product? So, for example, after Chao-Yang builds a good cell, he turns it over to me and I assemble it into a system. We have the whole chain here to test out any idea.”

“As a one-stop-shop, the BEST Center is unique. We’re always talking to each other. We couldn’t do these things by ourselves.”

—Krista Weidner

Chris Rahn is J. ‘Lee’ Everett Professor of Mechanical Engineering, co-director of the BEST Center, and associate dean for innovation in the College of Engineering at Penn State. Chao-Yang Wang is Professor and Diefenderfer Chair of Mechanical and Nuclear Engineering, and co-director of the BEST Center. Michael Hickner is Professor of Materials Science and Engineering and Chemical Engineering, and Corning Faculty Fellow.

This story first appeared in the Fall 2018 issue of Research/Penn State magazine.