Earlier this year, Goodyear, like all tire companies, has spent a lot of time and money developing tires with lower rolling resistance, which helps increase the fuel economy of conventional cars and the range of electric vehicles. Those efforts led Goodyear engineers to wonder if they couldn’t make the tires generate electricity.
Another idea was creating electricity through thermoelectricity, converting variations in temperature into electric voltage. Whether they’re sitting in the sun or spinning on the road, tires generate heat. Goodyear was looking to use thermoelectric materials (like bismuth telluride and tin selenide), to generate electricity from the difference between the hottest and coolest parts of the rubber. Again, the challenge was incorporating those materials without sacrificing elasticity and durability. Since then, researchers from the University of Wisconsin-Madison have been hard at work on their own accord to develop a tire that can harvest the typically wasted power produced from friction.
A team of UW-Madison researchers got together, led by Dr. Xudong Wang, to develop a nanogenerator that has the ability to harvest the energy from a car’s rolling tire friction, which will potentially make care tires a much more efficient product.
Xudong Wang’s team has developed a new way to harvest energy from rolling tires. The researchers used toy cars during the initial trials. (Credit: UW-Madison College of Engineering)
Xudong Wang, the Harvey D. Spangler fellow and an associate professor of materials science and engineering at UW-Madison, and his PhD student Yanchao Mao have been working on this device for about a year. The nanogenerator relies on the triboelectric effect to harness energy from the changing electric potential between the pavement and a vehicle’s wheels. The triboelectric effect is the electric charge that results from the contact or rubbing together of two dissimilar objects.
Wang says the nanogenerator provides an excellent way to take advantage of energy that is usually lost due to friction. “The friction between the tire and the ground consumes about 10 percent of a vehicle’s fuel,” he says. “That energy is wasted. So if we can convert that energy, it could give us very good improvement in fuel efficiency.”
The nanogenerator relies on an electrode integrated into a segment of the tire. When this part of the tire surface comes into contact with the ground, the friction between those two surfaces ultimately produces an electrical charge-a type of contact electrification known as the triboelectric effect.(Source: Gizmag