Nav: Home

New technology may give electric car drivers more miles per minute of charging

August 23, 2016

Researchers have designed a thin plastic membrane that stops rechargeable batteries from discharging when not in use and allows for rapid recharging.

The patent-pending technology controls how charge flows inside a battery, and was inspired by how living cell membranes transport proteins in the body. It could find applications in high powered "supercapacitors" for electric cars and even help prevent the kinds of fires that plagued some models of hoverboards recently.

In the journal Energy & Environmental Science, the Ohio State University engineers describe the "smart" membrane that they hope will enable the development of a new category of fast-charging and powerful batteries called "redox transistor batteries" for automobiles that will travel farther on a single charge.

Along the way, they analyzed the performance of the leading hybrid and electric car batteries, and discovered something that, to their knowledge, has never before been stated outright. The best eco-car makers appear to have hit a performance limit, and that limit is 0.4 miles -- less than half a mile of driving -- per minute of charging.

Put another way, today's very best eco-friendly cars can travel around 200 miles after an 8-hour charge, while gas-powered cars can cover the same distance after only one minute spent at the pump. The researchers hope their new technology can boost electric car batteries to provide up to tens of miles per minute of charge.

"That's still an order of magnitude away from the equivalent measure in gasoline, but it's a place to start," said Vishnu-Baba Sundaresan, an assistant professor of mechanical and aerospace engineering at Ohio State and leader of the study.

Sundaresan said that today's hybrid and electric cars are hitting the performance limit because of how charge is stored in conventional batteries. He also believes that his new membrane technology might be the only way to push past that limit until entirely a new category of battery electrodes are developed.

"Research over the last 50-plus years has focused on advancing the chemistry of battery electrodes to increase capacity," Sundaresan said. "We've done that, but the increase in capacity has come at the cost of robustness and the ability to rapidly charge and discharge batteries. Electric vehicle design is mature enough now that we know the limit they're reaching is because of the chemistry of lithium-ion batteries."

Sundaresan and doctoral student Travis Hery call their invention an "ionic redox transistor," and they're using it to develop a new kind of battery in which energy is stored in a liquid electrolyte--which people can recharge or empty out and refill as they would refill a gas tank.

"For everyday commuting, the electrolyte can be simply regenerated by plugging it into a power outlet overnight or while parked at the garage. For long road trips, you could empty out the used electrolyte and refill the battery to get the kind of long driving range we are accustomed to with internal combustion engines," Sundaresan said.

"We believe that this flexibility presents a convincing case for weaning our dependence on internal combustion engines for transportation."

Batteries such as lithium-ion batteries already have membrane separators that conduct charge and physically separate the anode and the cathode from each other, but even the best of these batteries lose charge over time. That's because membranes can't completely prevent charge from leaking between the anode and cathode, explained doctoral student Travis Hery. The internal chemical reactions are called self-discharge.

In the best-case scenario, self-discharge slowly converts some of the battery's internal energy into heat--a gradual power drain. In the worst-case scenario, the leakage causes batteries to overheat and even catch fire, as recently happened with the popular lithium-ion-powered hoverboards and Boeing's environmentally friendly Dreamliner fleet.

The phenomenon is called thermal runaway, and there are very few ways to shut it down once it starts. But Sundaresan and Hery believe their membrane, when used with a specially designed electronic control unit, can shut down charge transport and prevent thermal runaway at its onset.

The design is inspired by cell membranes in the body, which open and close to let cells perform biological functions. Openings in the cell wall respond to the electrical charge of molecules to expand or contract, and it's this principle that the engineers applied to the smart membrane.

They combined an electrically conductive polymer with a polycarbonate filter used for air and water testing. By controlling how they grew the conductive polymer chains on the polycarbonate surface, the researchers found they could control the density of openings in the resulting membrane.

When the battery is charging or discharging, the conductive polymer shrinks to open the holes. When the battery isn't in use, the polymer swells to close the holes.

In laboratory tests, the engineers found that their membrane reliably controlled charging and discharging in batteries powered by ions of lithium, sodium and potassium. They connected batteries to an LED light, programming the holes to open and close in precise patterns. The membrane allowed the batteries to function normally, but reduced charge loss to zero when the batteries were not in use.

The university will license the technology to industry for further development.

The same technology could prevent self-discharge in supercapacitors, which give high power and rapid recharge capability to some electric cars, buses and light rail transit systems.

While the researchers have proven that the membrane works with conventional batteries, what Sundaresan and Hery most want to do is use it as the basis of a new type of battery. They are working to combine a so-called redox flow battery, in which an electrolyte is pumped from the anode to the cathode to generate power, with their smart membrane to create the so-called "redox transistor battery."
-end-
This research was funded by the National Science foundation.

Contact:

Vishnu-Baba Sundaresan
614-247-6367
Sundaresan.19@osu.edu

Ohio State University

Related Batteries Articles:

A new concept could make more environmentally friendly batteries possible
A new concept for an aluminium battery has twice the energy density as previous versions, is made of abundant materials, and could lead to reduced production costs and environmental impact.
Overcome the bottleneck of solid electrolytes for Li batteries
On Aug 21st, Prof. MA Cheng from the University of Science and Technology of China (USTC) and his collaborators proposed an effective strategy to address the electrode-electrolyte contact issue that is limiting the development of next-generation solid-state Li batteries.
Dangerous wild grass will be used in batteries
Hogweed, which has grown over vast territories of Russia, can be useful as a material for batteries.
Self-repairing batteries
Engineers at the University of Tokyo continually pioneer new ways to improve battery technology.
A close look at lithium batteries
Batteries with metallic lithium anodes offer enhanced efficiency compared to conventional lithium-ion batteries because of their higher capacity.
Advances point the way to smaller, safer batteries
New Cornell research advances the design of solid-state batteries, a technology that is inherently safer and more energy-dense than today's lithium-ion batteries, which rely on flammable liquid electrolytes for fast transfer of chemical energy stored in molecular bonds to electricity.
The secret life of batteries
A world with faster-charging batteries begins with an understanding of how positively charged lithium ions move through the electrode to deliver energy.
Cartilage could be key to safe 'structural batteries'
Your knees and your smartphone battery have some surprisingly similar needs, a University of Michigan professor has discovered, and that new insight has led to a 'structural battery' prototype that incorporates a cartilage-like material to make the batteries highly durable and easy to shape.
Focusing on the negative is good when it comes to batteries
Fluoride-based batteries have the potential to last up to eight times longer than those in use today.
Building better batteries by borrowing from biology
Using knowledge of biological ion channels, Osaka University researchers developed a new crystalline material containing potassium that may one day replace the lithium-based technology currently used in rechargeable batteries.
More Batteries News and Batteries Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.