Are Lithium Ion Batteries Safe?

Tesla Lithium Ion
Steve Jurvetson via Flickr

They power our mobile computing devices, cordless tools and even our electric automobiles. Lithium ion batteries have enabled nothing short of a peaceful revolution in personal technology.

You could even make a strong case for them being a “green” technology: They don’t directly produce emissions that cause climate change; and since they’re rechargeable and long-lasting, they prevent the production (and disposal) of far many more single-use alkaline batteries.

Yet for all their good deeds, lithium ion, (or Li-ion) batteries have people asking a very important question: Are they safe?

Over the years, Li-ion batteries have amassed a thick file of bad press for their rare but frequent-enough penchant for spontaneously combusting. The batteries have been found guilty in so-called “exploding laptops,” super-heated cell phones, and in early 2013, they were implicated in electrical fires aboard the Boeing 787 Dreamliner passenger jet. Questions have been raised about the safety of electric cars, too, with critics often citing what they see as untrustworthy Li-ion batteries.

This article will sleuth out the facts from the fear-mongering over the Li-ion battery’s spotty background. With the hype put in its proper perspective, you can make an informed decision about whether this source of energy poses any real risk for you.

What Are Li-ion Batteries?

Sony, the big electronics maker, was the first to market with a rechargeable, practical Li-ion battery in 1991. It was a huge milestone in battery technology, as Li-ion cells can hold twice the energy content of their closest rival, nickel-metal hydride batteries. They can hold four times the energy or more of lead-acid batteries, which many of us are familiar with from jumpstarting our internal combustion engine cars.

But there’s a dark side to the wonder batteries. Their high energy content means they’re also more chemically unstable.

How Often Do Lithium Ion Batteries Burn Up, and Why?

In short, enforcing strict quality control is the key to making safe Li-ion batteries. According to BatteryUniversity.com, a frequent culprit in Li-ion battery fires is outside contamination. Metal particles, if concentrated enough, can form a short circuit inside the battery. Given a large enough short, the batteries can heat up to a point where they spew gases under pressure – a phenomenon that batteryologists call “thermal runaway” and its consequence, “venting with flame.”

It isn’t easy keeping out stray metal particles – they’re the size of dust grains. Reputable and established battery makers can do it, by investing in modern, complex and fastidiously clean facilities. Cheaper manufacturers can provide lower-cost lithium cells, but those cheap batteries are notorious for warping and blistering at a high rate.

Occasionally, even a major electronics maker like Apple or Dell will get a bad lot of batteries from one of its subcontractors. Electric automaker Fisker had such a stroke of bad luck in 2012, prompting a recall when it learned its supplier A123 systems provided a faulty battery design.

Alternatives to Lithium Ion Batteries

It’s highly improbable that anyone would go out today and buy a smartphone with half the battery life of his or her previous one. Yet that’s what you’d be signing up for if you downgraded to the next-most powerful power source, nickel metal hydride batteries. You could, of course, forego the freedom afforded by battery power and plug in everywhere with your devices.

The truth is no power source is 100 percent safe. Lead-acid batteries are notorious for exploding when overcharged or charged near sparks or open flame (like a lit cigarette). And when it comes to cars, Li-ion batteries in electric vehicles so far have an enviable track record compared to internal combustion vehicles. There are more than a quarter million fires in conventional vehicles every year, according to the National Fire Protection Association.

As for the sporadic reports of electric cars catching on fire? In almost zero cases was the cause attributable to Li-ion batteries (Fisker replaced batteries in a 2012 action, citing faulty battery design, along with a separate recall to replace a defective cooling fan system.)

In one highly publicized but largely misunderstood event, the National Highway Traffic Safety Administration exonerated the Chevrolet Volt after a torture testing session caused a battery fire. The part missing from many news stories: the fire finally erupted three weeks after the Volt was crashed and left lying on its back.

The agency concluded from its tests, “Based on the available data, NHTSA does not believe that Chevy Volts or other electric vehicles pose a greater risk of fire than gasoline-powered vehicles.”

The Verdict

Li-ion batteries make our lives more convenient, productive and fun. For the most part, they’re safe, but they carry risks as does any modern, high-energy power source. Your best bet, if you ever have to replace a set, is to buy manufacturer-approved, genuine replacements only. The few extra bucks you’ll pay over no-name brand batteries are a small price for reducing the risk to your precious gadgets and data.

Would you fly in a plane that used lithium ion batteries in its electrical system? Drive a Li-on powered car? Why or why not?