Uber will bring you flying taxis, if you can help build a magical battery

Our eVTOL future?
Our eVTOL future?
Image: Uber
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Fort Lauderdale, Florida

Uber has a bold vision for the future of urban transport: flying cars. By 2023, the world’s highest-valued startup aims to make small aircraft rides, with vertical takeoff and landing, an affordable option for daily commuters (think San Francisco to San Jose in 15 minutes). Better still, to ensure a sustainable future for its business, Uber wants its flying machines to be 100% electric—and with energy coming from only clean sources—from the start. There will be pilots early on, but by 2030 the system will be fully autonomous, Uber says.

In a swanky presentation at the 2018 International Battery Seminar on March 27, Celina Mikolajczak, Uber’s director of engineering for energy-storage systems, laid out these impressive goals—then concluded that there’s no way for the company to meet them without help from others.

“The battery we need to do this really well…does not exist,” Mikolajczak admitted. She had come to Florida with a challenge for the battery-expert community: develop a battery that is lighter and has more storage capacity than anything produced so far.

Then came time for questions. “Do you have a back up plan?” asked Jeff Dahn, one of the world’s leading battery experts. The audience exploded in laughter, grounding Uber’s planes before they even took off.

Facing physics

Uber’s presentation was even more fantastical when considered in juxtaposition to the talk Dahn gave about his work just before it. Dahn, one of the world’s leading battery experts, is currently working on next-generation batteries for Tesla.

In his presentation, he noted how, despite decades of development, researchers have to cut the battery open to study every important thing going on inside it. That means they can’t always test the same battery at different times in its lifecycle.

Dahn’s team at Dalhousie University found a way around the crude technique. Inside every lithium-ion battery, there’s a liquid electrolyte that transports charged particles between the positive and the negative electrodes. Dahn said that you can find out crucial details about the health of the battery at different times in the lifecycle by studying how long it takes for a battery to freeze and defreeze, when compared with how the battery fared in the same process when it was new. In theory, this discovery could help lead scientists to build the new batteries Uber needs. But it’s also a strikingly modest step forward in battery science, and not the giant leap of Uber’s dreams.

The presentation seemed appropriate for one of the world’s premier conference on batteries. Many in the crowd of battery-community experts were taking notes furiously during Dahn’s presentation. As soon as Uber’s presentation began, however, they laid down their pens. The goals seemed too far from today’s reality.

Uber’s flying cars will need not only new aircraft designs but also a whole new regulatory system to support a new form of urban transport. Crucially, to be commercially successful, Uber’s planes will need a battery that is light, cheap, long-lasting, quick-charging, and powerful enough to supply energy to an aircraft big enough to carry a few people.

Here are the numbers that Mikolajczak’s dream battery needs to hit, in order to power a fleet of flying cars with a range of about 60 miles (100 km):

  • Battery size: 150 kWh (kilowatt-hours)
  • Battery pack energy density: 300 Wh/kg (watt-hours per kilogram)
  • Battery life: 500 cycles (by 2023); 1,000 cycles (2028); 2,000 cycles (2032)
  • Peak charge time: add about 20% capacity in five minutes

To put that in context, here are the stats for one of the most advanced electric cars on the market—the 2017 Tesla Model S 100D, which has a range of 335 miles (540 km):

  • Battery size: 100 kWh
  • Battery pack energy density: 200 Wh/kg
  • Battery life: at least 500 cycles
  • Peak charge time: add about 50% capacity in 30 minutes

By those figures alone, it might seem like Uber’s dream battery is feasible.

But the best lithium-ion technology of today is near the limit of its energy density. There are materials that can theoretically pack in more energy, but they would require a new chemistry. And industry experts say that bringing new chemistry to market can take as long as 15 years, because a lot goes into ensuring a reliable product: from securing the supply chain to performing rigorous safety tests. (One of the reasons for excitement around Dahn’s talk was that his technique, when commercialized, could reduce the time spent on these tests.)

Mikolajczak notes that the US department of energy is currently spending $50 million to create a battery with an energy density of as much as 500 Wh/kg by 2021. But industry experts know well that lofty government goals don’t always make for attainable research targets.

In the end, the reality may be somewhere in the middle. Given the extensive interest in new battery technology, not just for flying cars but many other more mundane applications, it may not take as much as 15 years to get there. But it’s unlikely we’ll hit the goal before Uber’s stated goal of 2023.

Uber watchers say flying cars were a pet project (pdf) of its former CEO Travis Kalanick. Though Uber has invested in building out the team for the project even after Kalanick’s departure, those that follow the company closely say the project seems more a PR exercise than a serious commercial venture.

Fly away… soon

People have dreamed of flying cars for more than a century. But commercial constraints have stopped them from becoming a reality. For instance, older designs of flying cars needed a runaway to take off and land, which is not something most people who want—and can afford—a flying car are able to spend money building.

That’s finally changing. The technology of small drones has matured to the point where developers can build flying cars that can take off and land vertically—eliminating the need for runways. If there has even been a time when flying cars could become a reality, it is now. Terrafugia, a Chinese-owned US startup, says its gas-powered flying car, the TF-X, will go on sale next year, for somewhere between $200,000 and $300,000—comparable to the sticker price of a luxury supercar.

Uber’s insistence on being all-electric from day one is noble, but not pragmatic. If Uber was serious about its aerial ambitions, it’d be better off building an initial fleet made up of TF-X’s, rather than waiting for an all-electric fleet that relies on development of a super battery on an “aggressive schedule,” as Mikolajczak puts it. Starting with reliable gas-powered planes would mean the company would face regulators sooner rather than later, smoothing the eventual transition to electric versions. It would also buy the company time to secure its dream battery. When I asked Mikolajczak why Uber isn’t considering a pilot program using gas-powered aircraft, she wouldn’t give me an answer. Uber confirmed that it may design batteries, but it won’t manufacture them. It also confirmed that it definitely won’t design or manufacture its own flying cars.

Seen from another angle, however, it may be good to have Uber as an instigator. In May 2017, it hosted an “Elevate Summit” in Dallas, Texas, inviting anyone who wanted to work on flying taxis, and another one is lined up for May this year in Los Angeles, California. The startup could create just the right chemistry among industry people by bringing together what has been a disparate group to work towards more unified goals. For the innovators, it doesn’t hurt to know that a $70-billion company is ready to purchase their products if they get them to hit those targets.