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A Winthrop paramedic's Samsung Galaxy Note 7 smartphone, after it exploded while charging during an overnight shift at Action Ambulance Services early September.
A Winthrop paramedic's Samsung Galaxy Note 7 smartphone, after it exploded while charging during an overnight shift at Action Ambulance Services early September.Action Ambulance Services.

There's nothing like a loud explosion and a burst of flame to get your attention. That's why everybody's suddenly talking about one of the most boring technologies around — rechargeable batteries.

Lithium-ion batteries inside dozens of Samsung Corp.'s new Galaxy Note 7 smartphones have exploded and burned over the past month. On Friday, the US Consumer Product Safety Commission issued a statement urging phone owners to switch them off and unplug them. The agency said it was working with Samsung to launch a nationwide recall of the phones, though Samsung had already said it would recall all 2.5 million of the phones it has distributed worldwide. Also, US and European aviation regulators have warned travelers not to carry the phones in checked luggage or switch them on or charge them during flights, though the agencies stopped short of a total ban.

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Meanwhile, the popular two-wheeled scooters known as "hoverboards" earlier this year were beset with a spate of battery fires that damaged homes and businesses.

These are just the most recent fiascos attributed to problems with rechargeable lithium-ion batteries, and there are plenty more to choose from. In 2013, the batteries in several Tesla Motors Model S electric cars caught fire after their battery casings ruptured in traffic accidents. And in the same year, Boeing Co. had to ground its entire fleet of 787 Dreamliner jets when their battery packs began to smoulder due to short circuits inside the batteries.

Let's not exaggerate the dangers. Billions of lithium-ion batteries are used every day to power laptops, smartphones, toys, and even hybrid cars. Failures like these are exceedingly rare. Still, disasters happen, and even when they don't, lithium-ion batteries are far from perfect. As we make more demands on our mobile devices, battery improvements aren't keeping up. Many smartphones can't make it through the day on a single charge, and those batteries lose their ability to hold a charge after a couple of years. Then we must either buy a replacement battery, or a whole new device.

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It makes you wonder if there isn't a better, safer way to power mobile devices. For now, there isn't. A few years ago, engineers hoped to replace batteries with fuel cells, which use hydrogen-based fuels such as alcohol to generate electricity, with water and heat as the only waste products. A small vial of liquid could keep a machine running for hours.

A Boston-area company called Lilliputian Systems, spun off from the Massachusetts Institute of Technology, spent $150 million to develop such a device. They promised a finished product in 2012, then in 2013. And then in 2014, Lilliputian shut its doors forever.

A British company, Intelligent Energy, which sells a system for use in remote regions without electricity, has built a prototype fuel cell for an Apple iPhone and hopes to bring a product to market next year. But there's good reason for pessimism. Only a last-minute cash infusion in May kept Intelligent Energy out of bankruptcy court.

For now, we're stuck with batteries, and the lithium-ion design is the gold standard. They're reasonably cheap and have high "energy density," meaning they pack a lot of power in very little space.

"Lithium-ion is the only promising battery that we have right now," said Isidor Buchmann, founder of Cadex Corp., a Canadian maker of battery testing equipment.

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But lithium-ion batteries are also finicky devices that must be built just right. Otherwise, short circuits can occur inside them, setting off a malignant chain reaction.

"A battery is really a bomb," said Qichao Hu, founder of SolidEnergy Systems, a battery- technology startup in Woburn.

That's because in a standard lithium-ion battery, the electricity flows through a flammable liquid, such as ethylene carbonate. In addition, the battery's electrodes can release oxygen when heated. Now imagine a short circuit in the battery, caused by a minor mistake at the factory. This short circuit generates intense heat, which releases oxygen, which mixes with the flammable liquid. Let the temperature rise too high, and eventually there'll be a loud bang.

SolidEnergy Systems is another MIT spinoff that hopes to solve the problem, but not by inventing an alternative to lithium-ion batteries. Instead, SolidEnergy is redesigning the innards of lithium-ion batteries, to make them less dangerous and more powerful at the same time.

Hu said that SolidEnergy has developed a battery solution using a nonflammable liquid. In addition, Hu's batteries would use a new kind of electrode material that should increase energy density, so it can crank out more power per ounce of weight.

"We can provide twice the capacity in the same volume," Hu said.

SolidEnergy has raised over $16 million in venture funding from multiple sources, including General Motors Corp.

There's lots of other work being done to upgrade batteries. Sony Corp. recently announced it will use a new charging system to make the standard batteries inside its smartphones last for up to four years, instead of the usual two, before they need replacement. And researchers at Sony and other companies are trying to build solid-state batteries that eliminate liquids that can catch fire.

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Still, nobody expects radical breakthroughs anytime soon.

"I think people with electronics come to expect these rapid advances," said Christopher Robinson, a battery analyst at Lux Research in Boston.

That often happens with microchips, but not with batteries. Instead, Robinson said, "it's just the steady incremental improvements that make the energy a little more dense, the batteries a little more safe."


Hiawatha Bray can be reached at hiawatha.bray@globe.com. Follow him on Twitter @GlobeTechLab.