SolidEnergy aims to power the next generation of drones and phones

Lithium-ion batteries power everything from smartphones to electric vehicles, and have changed our lives so profoundly that their development earned this year’s Nobel Prize in chemistry.

Now, Boston-based SolidEnergy is looking to make that technology obsolete.

Founded by Hu QiChao in 2012 at MIT, SolidEnergy is developing a lithium-metal battery that will double the energy density of its lithium-ion predecessor. But while the company says commercialization is imminent, proving safety on a mass scale remains a daunting challenge.

“The next battery revolution should be happening soon, and it’s going to be led by the lithium-metal battery,” Hu said at the MIT conference where he was named one of the “30 under 30 innovators” in September.

If history is any guide, the timing for such a revolution seems about right: Since the lead-acid battery was developed in 1870, the past five major breakthroughs in battery technology all happened 30 years apart, with energy density doubling each time.

And it has been almost 30 years since Sony sold the first lithium-ion batteries in 1991.

The idea of a lithium-metal battery is not new, but safety concerns have prevented the technology from being commercialized. This is because lithium metal is highly reactive. When charging, typical lithium-metal batteries tend to form needle-like structures that can pierce the separator, which in turn could create a short circuit and cause a fire or explosion.

SolidEnergy has come up with a liquid electrolyte solution that its says reduces the risk of combustion. “Even today’s lithium-ion battery still catch fire or explode. We just need to lower lithium-metal battery’s chance of fire to as low as the existing batteries on the market,” Hu said.

Hu, who was born in central China but moved to New York at age 12, saw enormous opportunities in both countries for a more efficient rechargeable battery. Asia’s growing dominance in battery technology, however, led him to choose Shanghai for SolidEnergy’s first large manufacturing facility, which opened in late 2019.

The factory will supply lithium-metal batteries to customers including Apple and Huawei, as well as Chinese robot maker DJI and several other drone and satellite makers, according to two people familiar with the situation. However, none of the big-name clients have any immediate plans to use the lithium-metal battery in actual products and will instead use them mostly for test purposes, the people added.

And despite SolidEnergy’s optimism, experts say it may take a few more years before the new battery finds its way into consumer devices, particularly electronics like smartphones.

“The scrutiny people place on consumer electronics battery is even greater compared to cars or other industries because people bring them everywhere. [That is the case] especially after the Samsung Note 7 safety incident,” said William Chueh, associate professor of materials science and engineering at Stanford University and senior fellow at the Precourt Institute for Energy.

“Safety issues in batteries are measured in [incidents] per million [batteries], which means that lithium-ion batteries today have extraordinarily high safety records,” Chueh added.

Because solid lithium metal is much more reactive than lithium-ion, it is very unlikely that companies will adopt the batteries until it can be proved that they have a similarly high level of safety, according to Chueh.

That is why the new factory in Shanghai is critical for SolidEnergy — and in some ways for the lithium-metal battery industry as a whole. As the largest manufacturing facility of its kind so far, it puts SolidEnergy closest to having enough production capacity to measure safety on the scale of incidents per million batteries.

SolidEnergy’s Shanghai factory is located about a 40-minute drive from the city center, in the Jiading district that is also home to dozens of electric vehicle manufacturers. The factory covers more than 20,000 sq. meters, but the majority of its floorspace was empty when Nikkei visited in October, as only one production line had been set up.

“We don’t have enough orders from customers for us to put all the space into use,” said Tang Yun Fei, director of admin and human resources at SolidEnergy Shanghai.

“It’s like a chicken and egg problem. You don’t have enough clients without an acceptable safety record, but you can’t manufacture enough batteries to get the per-million records before you have enough clients to make that many batteries,” said Hu.

However, with the new research and manufacture facility in Shanghai, Hu said the company has been gaining more Chinese customers and demand is picking up. SolidEnergy hopes to scale up production to tens of thousands of cells per month next year.

After testing SolidEnergy’s pilot line of lithium-metal batteries in drones for more than three years, Hu and his team are now eyeing something bigger: electric vehicles.

In January 2011, China selected Shanghai as the country’s EV pilot city and the Jiading district as the EV international demonstration zone, a designation that comes with attractive government tax incentives for companies setting up shop there.

“The Jiading factory location is perfect for us because we want to be close to our clients,” said Barron Wu, SolidEnergy China’s supply chain director.

A battery industry veteran, Wu left DJI, the market leader in the civilian drone industry, and joined SolidEnergy in 2018, when the company decided to build the world’s largest and first mass production facility of lithium metal batteries.

“I was in charge of battery purchase at DJI and I know how important batteries are to industries like drones. Twice the battery life means twice the flying range, which is a game-changer for drone-makers,” Wu said. “It’s the same thing for EVs. Longer battery life gives them a longer range, and range limit has been one of the main reasons keeping people from buying electric vehicles.”

Once lithium-metal battery replaces the existing rechargeable batteries, with the doubled energy density, electric vehicles can be made smaller and lighter with twice the driving range.

Electric vehicles is a major goal for SolidEnergy in the near term, but Hu and his team are dreaming even higher for the future.

“The flying car technology is pretty much perfected in every other aspect except the energy source,” Hu said. “How to generate enough power to get cars off the ground without the batteries weighing them down is one of the final hurdles to cross. The lithium-metal battery is the solution.”

Automaker are already taking note of lithium metal’s potential. Volkswagen and General Motors have signed up to test SolidEnergy’s batteries, according to two sources familiar with the matter. General Motor’s venture arm is also an investor in SolidEnergy, one of the sources added.

To date, SolidEnergy has raised more than $70 million. The company has started generating revenue since last year, and Hu said it aims to turn profitable in 2020.

“SolidEnergy has not been around long enough to really examine how their batteries will perform in the long run, and everything in their lab is very propriety so it’s hard to know what’s really going on right now,” said Stanford’s Chueh. “But they are up to something very exciting.”

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