If Boeing is having trouble with the batteries in its 787 Dreamliners, it is not alone. "As 21st century technology strains to become ever faster, cleaner and cheaper, an invention from more than 200 years ago keeps holding it back," writes the AP's Seth Borenstein. That invention would be the battery. "It's why electric cars aren't clogging the roads and why Boeing's new ultra-efficient 787 Dreamliners aren't flying high," he continues.
He reminds us that in 2006 and 2007, "more than 46 million cell-phone batteries and 10 million laptop batteries--all lithium-ion--were recalled because of the risk of overheating, short-circuiting, and exploding." It almost makes you want to scrap your lithium-powered laptop for one of the old steam-powered models of yesteryear.
Borenstein explains why we tolerate lithium-ion batteries, and why Boeing demands them: they "store more energy at a higher voltage and a lighter weight than earlier types." But these things have been around (and exploding?) for 25 years. What is the next big battery thing? "None of the 10 experts who talked to the Associated Press said they know what that big thing will be yet, or when it will come," Borenstein writes.
Gautam Naik of The Wall Street Journal explains, in a story headlined "The Science Behind Dreamliner's Batteries," that the chemistry that makes lithium-ion batteries so light and powerful is precisely what "may increase their risk of overheating and catching fire." The batteries on the Dreamliner are continually charged by the plane's generators, but when the batteries become overcharged, the electrolyte--the chemical mix that resides between the batteries' two electrodes--can break down and generate heat, Naik reports. So far, there is no evidence that the plane's batteries were overcharged.
Chemists call it "thermal runaway," a process that can generate more and more heat until the battery ignites. Naik tells us temperatures can reach between 570 and 750 degrees Fahrenheit. Not a comforting thought when you're cruising at 36,000 feet. Engineers don't yet know whether that's what happened to the Dreamliner's batteries, Naik reports.
Craig Timberg at The Washington Post says even model-plane enthusiasts know the risks of lithium-ion batteries. He describes a scale model crashing to earth in a puff of smoke seconds after takeoff with an incinerated battery. "I've had buddies blow the ends of their fingers off with them," one hobbyist tells Timberg.
But Kevin Bullis at Technology Review is reassuring. Lithium-ion battery fires "are extremely rare," he writes, "and usually result from damage to the battery--such as piercing or overcharging--or problems with the manufacturing process."
Extremely rare? I guess I'll keep my laptop.