The future will be battery-powered

The future will be battery-powered


 
The battery might be the least sexy piece of technology ever invented. The lack of glamour is especially conspicuous on the lower floors of MIT’s materials science department, where one lab devoted to building and testing the next world-changing energy storage device could easily be mistaken for a storage closet.
At the back of the cramped room, Donald Sadoway, a silver-haired electrochemist in a trim black-striped suit and expensive-looking shoes, rummages through a plastic tub of parts like a kid in search of a particular Lego. He sets a pair of objects on the table, each about the size and shape of a can of soup with all the inherent drama of a paperweight.

No wonder it’s so hard to get anyone excited about batteries. But these paperweights — er, battery cells — could be the technology that revolutionizes our energy system.

Because batteries aren’t just boring. Frankly, they kinda suck. At best, the batteries that power our daily lives are merely invisible — easily drained reservoirs of power packed into smartphones and computers and cars. At worst, they are expensive, heavy, combustible, complicated to dispose of properly, and prone to dying in the cold or oozing corrosive fluid. Even as the devices they power become slimmer and smarter, batteries are still waiting for their next upgrade. Computer processors famously double their capacity every two years; batteries may scrounge only a few percentage points of improvement in the same amount of time.

Early prototypes of Sadoway's battery cell.
Early prototypes of Sadoway’s battery cell.Grist / Amelia Urry

Nevertheless, the future will be battery-powered. It has to be. From electric cars to industrial-scale solar farms, batteries are the key to a cleaner, more efficient energy system — and the sooner we get there, the sooner we can stop contributing to potentially catastrophic climate change.

But the batteries we’ve got — mostly lithium-ion — aren’t good enough. There’s been some progress: The cost of storing energy has fallen by half over the last five years, and big companies are increasingly making marquee investments in the technology, like Tesla’s ‘gigafactory.’ But in terms of wholesale economic transformation, lithium-ion batteries remain too expensive. They are powerful in our devices, but when you scale them up they are liable to overheat and even, occasionally, explode.

No wonder it’s so hard to get anyone excited about batteries. But these paperweights — er, battery cells — could be the technology that revolutionizes our energy system.

Because batteries aren’t just boring. Frankly, they kinda suck. At best, the batteries that power our daily lives are merely invisible — easily drained reservoirs of power packed into smartphones and computers and cars. At worst, they are expensive, heavy, combustible, complicated to dispose of properly, and prone to dying in the cold or oozing corrosive fluid. Even as the devices they power become slimmer and smarter, batteries are still waiting for their next upgrade. Computer processors famously double their capacity every two years; batteries may scrounge only a few percentage points of improvement in the same amount of time.

Early prototypes of Sadoway's battery cell.
Early prototypes of Sadoway’s battery cell.Grist / Amelia Urry

Nevertheless, the future will be battery-powered. It has to be. From electric cars to industrial-scale solar farms, batteries are the key to a cleaner, more efficient energy system — and the sooner we get there, the sooner we can stop contributing to potentially catastrophic climate change.

But the batteries we’ve got — mostly lithium-ion — aren’t good enough. There’s been some progress: The cost of storing energy has fallen by half over the last five years, and big companies are increasingly making marquee investments in the technology, like Tesla’s ‘gigafactory.’ But in terms of wholesale economic transformation, lithium-ion batteries remain too expensive. They are powerful in our devices, but when you scale them up they are liable to overheat and even, occasionally, explode.

Those canisters he showed me were early prototypes of cells for a “liquid metal battery” he started researching a decade ago.

“I started working on batteries just because I was crazy about cars,” Sadoway tells me. (His desktop background is a 1961 Studebaker Avanti he sold a few years ago. He keeps the picture around the way one would memorialize a family pet.) In 1995, he took a test drive in an early Ford electric vehicle and fell in love. “I realized the only reason we don’t have electric cars is because we don’t have batteries.”

So Sadoway started thinking. He had some experience with the process of refining aluminum, and he wondered if that could be a model for a new, unorthodox kind of battery. Aluminum smelting is a dirt-cheap, energy-intensive process by which purified metal is boiled out of ore. But if that one-way process could be doubled up and looped back on itself, maybe the huge amount of energy fed into the molten metal could be stored there.

In some ways, that’s insane — the molten battery would have to run around of 880 degrees F, only slightly cooler than the combustion chamber of a car engine. But it’s also a bizarrely simple concept, at least to an electrochemist. It turns out assembling a cell of a liquid metal battery cell is as easy as dropping a plug of metal, made up of two alloys of different densities, into a vessel and pouring some salt on top. When the cell is powered up, the two metals melt and divide into two layers automatically, like salad oil floating on vinegar. The molten salt forms a layer between them, conducting electrons back and forth.

But even with a promising start, developing a new battery is a glacially slow process, Sadoway says. Early funding from ARPA-E and the French oil giant Total helped him get the idea off the ground, but sustaining research for the years needed to build any brand new technology is expensive. Venture capitalists are shy about drawn-out engineering projects when there are so many software startups promising fast profits.

“In any capital-intensive industry, industry will stand in the way of innovation,” Sadoway says. Existing battery companies have too much invested in the status quo to be much help, he says. Lithium-ion came from outside the established battery industry of its time, he points out; the next battery will have to do the same.

The molten metal battery has long since moved out of the basement lab. In 2010, Sadoway started the battery company Ambri with several of his former students, then moved HQ into a manufacturing facility 30 miles west of Cambridge to the town of Marlborough. Now, Ambri employs about 40 people and is busy building prototype battery packs out of hundreds of the molten metal cells.

Sadoway says Ambri is less than a year away from deploying its first commercial models. All signs have been hopeful so far, he says. At the manufacturing facility, some test cells have been up and running for almost four years without showing any signs of wear and tear. Getting the assembled battery packs, each consisting of 432 individual cells, to work was trickier. But after ironing out some pesky issues with the heat seals, the battery packs can reach a self-sustaining operating temperature, hot enough to charge and discharge without any extra energy input. Now Ambri is in the middle of raising another round of funding, enough to reach market-ready production mode.

On my way out the door, I say that, for all the difficulty and delay, it seems like this battery could really be close. “I hope so,” Sadoway says, looking almost wistful. “Maybe this is it. I’d like to see that.”

coin battery
Grist / Amelia Bates

A crowded field

The molten metal battery isn’t the only moonshot battery. It’s not even the obvious front-runner. Other technologies are pushing ahead, quietly and without fanfare, from “iron flow batteries” to zinc- and lithium-air varieties.

Like Sadoway’s project, many of these untested technologies are funded initially by grants from ARPA-E. “These are very early stage, high-risk technologies,” says Rohlfing, the agency’s deputy director. “We take a lot of shots on goal.”

One especially promising contender in the better battery battle is the Pittsburgh-based company Aquion, whose founder, Carnegie Mellon professor Jay Whitacre, set out in 2008 to design the cheapest, most reliable battery you could make.

The result is something colloquially called a “saltwater battery.” It looks, more or less, like a Rubbermaid bin full of seawater. All of the materials in the Aquion batteries are abundant and easily obtained elements, from salt to stainless steel to cotton. What’s more, none of those materials carry the risks of a lithium-ion battery.

“Our chemistry is very simple,” says Matt Maroon, Aquion’s vice president of product management. “There’s nothing in our battery that is flammable, toxic, or caustic.”

aquion-batteries-at-stone-edge-farm
Aquion Energy

It’s also stupidly easy to assemble. “Our main piece of manufacturing assembly equipment comes out of the food packaging industry,” Maroon says. “It’s a simple pick-and-place robot that you’d find at Nabisco, putting crackers inside of blister packs.”

Aquion batteries have been on the market for nearly three years, installed in both homes and utility-scale facilities. Overall, Aquion has 35 megawatt hours of storage deployed around the world in 250 different installations. One in Hawaii has been up and running for two years; last year, the battery-plus-solar system powered several buildings for six months without ever falling back on a diesel generator.

“We need to get more of these things out into the field,” says Rohlfing. “Right now, if I’m a utility or a grid operator and I want to buy storage, I want to buy something that comes with a 20-year warranty. The technologies we’re talking about aren’t at that stage yet.”

But they’re getting close. Another ARPA-E-funded project, Energy Storage Systems, or ESS, announced last November that it would install one of its iron-flow batteries as part of an Army Corps of Engineers microgrid experiment on a military base in Missouri. ESS has also installed batteries to help power an off-grid organic winery in Napa Valley — for that matter, so has Aquion. As more and more of these one-off experiments prove successful — and more of these new kinds of batteries prove their worth — the possibility of a battery-powered energy system comes a little closer.

But will batteries ever be, well, cool? That’s a harder question. Aquion’s Matt Maroon has been working in the field since 2002, soon after he left college. At conferences, Maroon was often the youngest person in the room by 30 years. He was sure he wouldn’t be “a battery guy” for his whole career.

Fifteen years later, he’s still a battery guy — but he’s no longer the youngest person in the room. More students are starting to get involved with batteries, and people are starting to take notice. “It’s still not as a cool as working at Apple,” he says. “But I think people recognize its importance and that kind of makes it cool.”

“Or I hope so,” he laughs. “I’ve got a 9-year-old daughter. So I’d like to work on something that she thinks is cool someday. That’s my ultimate goal.”

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