Researchers in Japan say they have developed a battery with almost twice the energy density of the battery used in a Tesla Model 3 car, offering hope that much longer-lived batteries could soon make their way to mobile phones, electric vehicles—and even electric passenger planes.
The new lithium-air battery, developed by Japan’s National Institute for Materials Science (NIMS) and backed by Japanese conglomerate SoftBank, is claimed to have a record-breaking energy density of more than 500 watt hours per kilogram (Wh/kg)—nearly double that of the 260 Wh/kg lithium ion Panasonic battery found in Tesla’s Model 3.
The team also claim the battery holds up well under repeated charges, saying: “the repeated discharge and charge reaction proceeds at room temperature. The energy density and cycle life performance of this battery are among the highest ever achieved.”
The 500 Wh/kg figure is important because engineers regard that as the threshold for the point at which regional electric passenger aircraft become possible. The electrification of aircraft offers the promise of sustainable, efficient and close-to-silent air travel compatible with a zero carbon future. But numerous technological barriers stand in the way of that goal—most significantly the fact that current-generation lithium-ion batteries are heavy relative to the amount of electrical energy they can store.
I asked Patrick Wheeler, Global Director of the Institute of Aerospace Technology and a professor in the Department of Electrical and Electronic Engineering at the University of Nottingham in the U.K., for his views on the significance of the breakthrough.
“The figures they’re talking about are interesting because they’re at that pinch point where it will become feasible to have a medium distance electric flight—that’s a bit of a holy grail,” Wheeler said. “If you want all-electric flight over a large distance, the current lithium ion batteries aren’t going to do it, because they become too big and too heavy.”
But Wheeler emphasized that the news could be at least as relevant to other forms of transport that are already in use.
“What this does is give us a battery that is significantly better in energy storage than we have today,” he said. “Range anxiety is still an issue for electric vehicles, so if you can replace the battery pack an electric car today with something that takes you twice, three times as far, that’s going to be a good place to be.”
Wheeler noted that little detailed technical information was currently available on the NIMS unit, but he thought that such a battery, should it hold up under real-world conditions, could be brought to market fairly quickly owing to massive interest in electrification.
“If it proves that it will scale up, I can imagine that development is going to be fairly rapid, because the demand is there,” he said. “You have governments saying they want all electric vehicles and transport by 2030, 2035. There’s a good reason for a lot of people to want to invest in that—both governmental and commercial.”
Returning to the prospect of electric planes, Wheeler thought that the NIMS announcement was encouraging, but noted many other challenges would have to be overcome before electric aircraft became a common sight on the world’s runways—not least when it comes to charging.
“If you’re going down the route of rechargeable batteries on planes, charging the planes up as they’re sitting at the gate doesn’t look unfeasible,” he said. “But all that electrical energy has to come from somewhere: you need to make sure you have a zero carbon source for all that electrical energy, and the infrastructure to get it to the aircraft. That’s not insignificant, particularly at large airports.”
In the near term, another hurdle could prove to be legislative: the announcement from Japan coincides with news that Israeli company Eviation is gearing up to test what is purported to be the first electric passenger plane, dubbed Alice. But in the U.S., where Alice is due to take test flights in the next few weeks, the Federal Aviation Authority has yet to established any rules for electric aircraft, though it has issued “special conditions” for certain engines produced by MagniX, the firm that makes the engines used in the Alice.
At present, Alice’s specifications are modest. The plane can carry nine passengers a distance of just 506 miles at just under 290 miles per hour, using lithium-ion batteries that the company’s CEO has said make up 65% of the weight of the aircraft. So while these are still early days in the age of electric flight, advances of the sort described by the team at NIMS could prove a game-changer.
Courtesy of David Vetter from Frobes