Researchers at Penn State University are working on a new type of thin glass capable of storing energy, a material that could help make electric and plug-in hybrid vehicles more affordable and reliable.
Thin and flexible glass has already been widely commercialized for computer and electronic displays. An even thinner version – about one-tenth the thickness of typical displays – can be manipulated to store energy at high temperatures and for high-power applications, such as electric vehicles, wind turbines and grid-tied solar photovoltaics, according to Penn State’s Materials Research Institute.
The researchers came to this conclusion after testing a variety of alkali-free glass compositions and thicknesses, and comparing their energy density with the commercial polymer capacitors used today in electric vehicles to send energy from the battery to the electric motor.
Because those capacitors require a separate cooling system, they are large and bulky. But the 10-micron-thick glass tested by Penn State (and made by Nippon Electric Glass) retains a very high charge-discharge efficiency at temperatures up 356 degrees Fahrenheit, without requiring that extra cooling component.
The researchers worked in collaboration with Strategic Polymer Sciences to produce the glass in thin sheets, using the same roll-to-roll process used by leading glass manufacturers — which means the material should be relatively straightforward to manufacture.
The glass was then coated with polymers that increased the energy density by 2.25 times and made them less subject to sudden failures, says Penn State post-doctoral researcher Mohan Manoharan, who lead the study.
“These flexible glass capacitors will reduce weight and cost if replacing polypropylene capacitors,” says Manoharan. “They could be used in any high energy density capacitor application — not only in electric vehicles, but in heart defibrillators or weapons systems such as the electric railgun the Navy is developing.”
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