It all began with a Youtube video. It was 2014, and a friend of Dan Steingart, professor of mechanical and aerospace engineering at Princeton, showed him a viral video of batteries bouncing. The clip, posted by an electrical engineer, demonstrated an intriguing phenomenon: drop a dead AA battery on your desk, and it will bounce. Drop a fresh battery, and it will land with a thud.

Steingart was intrigued, and rather than taking the Internet’s word for it, he did what any good skeptical scientist would do: he tested it out. “I verified it quickly with two batteries sitting on my desk,” Steingart recalled. As it happens, Steingart is not just any scientist, but one who specializes in researching batteries, and the bouncing Energizer was a phenomenon that he had not noticed in his years of studying batteries.

However, Steingart was not content to observe the difference in bounciness between dead batteries and fresh ones. He wanted to understand why it was happening. More questions had to be answered: What about half-dead batteries? Would they bounce half as much as fully dead ones? “Nobody had studied this before,” Steingart said.

Steingart and some of his doctoral students went about systematically studying how batteries with different charge levels bounced. They dropped batteries through a plexiglass tube, set up a microphone, and measured the time between bounce noises to determine how high each bounce was.

They also discovered the reason for the bounce by looking at x-ray scans of batteries from the Brookhaven National Laboratory and comparing the data with the results of their bounce tests. It had to do with the changes that take place within a battery as it discharges.

Batteries produce an electrical current by a reaction between zinc and manganese oxide. In a fully charged battery, the zinc is a powdery substance that flows easily, damping any potential bounces. But as the battery is used, the zinc oxidizes, forming hard, springy zinc oxide: the same chemical that gives a golf ball its bouncy core.

It turned out that a half-charged battery won’t bounce half as high. “It’s not a linear change,” Steingart said. “It’s not a straight line of bounciness between fresh and dead batteries: it’s a nonlinear curve. And anything that’s nonlinear is nearly always worth studying.”

The research, published in March, 2015, in the Journal of Materials Chemistry, was not only interesting, but commercially valuable. “We thought about this for a few months and there were a few experiments, and then we made inductive leaps,” he said.

Once the relationship between bounciness and electrical charge had been established, it became possible to determine exactly how much charge a battery had left just by bouncing it, up to a point (a battery will bounce its maximum height long before it is dead). It was also possible to use sound waves instead of shock waves from bouncing, meaning that you could measure the charge of a battery just using sound.

Steingart has wasted no time putting his discovery to use. He has founded a company, Feasible Inc., to commercialize the technology of using a tiny speaker and a computer to test the charge of a battery. If brought to market, the idea could solve a big inefficiency in battery and manufacturing and maintenance. Testing a battery, whether it’s newly made or already being used, can take several days, Steingart said.

He said his sound wave technique could measure battery life in a matter of minutes. If it pans out, Steingart’s technology could improve the efficiency of battery manufacturing and in theory bring the price of making and operating batteries down, helping them become a more viable energy storage medium compared to fossil fuels.

Steingart is just one of the researchers working at the Andlinger Center for Energy and the Environment, a building on Princeton’s north campus that was built with a $100 million grant from Gerhard R. Andlinger, a philanthropist, international business tycoon, and Princeton graduate. The Andlinger Center opened for business in the fall semester, and is about to host a seminar celebrating its public debut.

The three-day building opening celebration and symposium will begin Wednesday, May 18, and will host speakers from the Andlinger Center as well as leaders in energy research from around the world. Speakers include Emily Carter, the outgoing founding director of the Andlinger Center, who starts a new job as dean of engineering in July.

The roster of speakers also features Norman Augustine, retired CEO of Lockheed Martin; Ralph Cicerone, president of the National Academy of Sciences; Richard Kauffman, chairman of energy and finance for New York State; Elizabeth Sherwood-Randall, deputy secretary for the U.S. Department of Energy; Ellen Williams, director of research projects for the Advanced Research Projects Agency — Energy; and several Andlinger Center professors. Tickets are free. Register at

The symposium is a chance for Princeton to show off its newest research facility. The 129,000-square-foot research center, designed by New York-based architects Tod Williams and Billie Tsien, appears to be multiple buildings but is actually one gigantic structure, about 60 percent of which is underground. At surface level, gardens, plazas, and courtyards decorate the outside.

The inside contains classrooms, a lecture hall, and advanced research and teaching laboratories. To prevent interference with high-tech equipment, such as electron microscopes, anything in the building that could create interference, such as the elevator, is covered in aluminum shielding.

The building, which also incorporates “green” features, reflects the Andlinger Center’s mission to research sustainable energy production, improve energy efficiency, and protect the environment (U.S. 1, January 28, 2015). The center was founded in 2008 and work on the building began in 2012. Before the facility was constructed, faculty members were scattered all over campus.

Researchers there are studying ways that humanity can produce energy cleanly and use it more efficiently. Professors at the center are studying smart buildings, biofuel, solar power, climate change, advanced materials, nuclear power, and many other subjects. University officials say part of the reasoning behind putting all these projects under one roof is to encourage collaboration and an exchange of ideas between different fields related to energy and the environment.

Steingart grew up on Long Island where his father is a doctor and his mother is a retired attorney. Growing up, Steingart lived in a place where public transportation was a reliable option for everyone. But after graduating from Brown with a bachelor’s degree, he headed to the University of California-Berkeley, where he would earn a doctorate in engineering. On his way across the country, he saw firsthand how dependent much of the population was on their cars. What would happen to them when the oil ran out?

“I had traveled a bit beforehand but I never really went through rural expanses,” Steingart said. “Driving across the country was my first exposure to the great expanses of the U.S., and the real reliance on cars and oil outside of places where you had sufficient to good public transportation.”

The trip, which he took around 2000, inspired Steingart to specialize in batteries when he arrived at Berkeley. Nowadays, the threat of running out of oil has diminished. Instead, Steingart now believes we have the opposite problem.

“The reality is we probably have too much oil,” he said. “It’s too easy to use, and we’re too dependent on it … the real challenge of oil is more a problem of gluttony rather than famine right now.”

While Steingart is involved in the nuts and bolts of battery research, he often thinks about the broader view of the role of the batteries in the production and use of energy. Better, cheaper batteries could improve the economy in a multitude of ways. One of Steingart’s other research projects involves using batteries in the power grid. Currently, electrical plants have no means of storing the power they produce. That means they have to crank up power output as soon as it is needed during times of peak demand, such as a hot day when a lot of people turn on the air conditioning. All that power generating facility goes unused in times of low demand.

If the power grid had a way to smooth out that electricity production, such as storing it in batteries located close to where the electricity was used, it could get away with having a much smaller power plant. The system would also be more resilient in case of a natural disaster such as a hurricane. Furthermore, because power lines suffer the most wear and tear when they are carrying peak power, reducing the peak load would make them last a lot longer and reduce maintenance costs.

“I’m working on how to make a really cheap battery that lasts a long time for grid-scale applications,” Steingart said. “Grid-scale energy storage at its most daring will not allow us to go fully renewable, but it can iron out some of the stochastic nature of solar and wind power,” he said.

With batteries acting as “shock absorbers” to kick in during times of peak demand, the power grid could become tremendously more efficient, thereby using less resources and creating less pollution.

As climate change becomes a more important issue, Steingart and the other researchers at the Andlinger Center are doing critical work at a time in history when energy efficiency could be of crucial global importance.

“It’s just a very exciting time to be in batteries,” he said. “When I started, it was a very sleepy field and I kind of Forrest Gumped my way into it. I got pretty lucky in that regard.”

Andlinger Center for Energy and the Environment, 86 Olden Street, Princeton 08544; 609-258-4899; Emily Carter, founding director.

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