Will Your Headphones Explode?

Perhaps you remember the story from two weeks ago. A woman (pictured) wearing headphones on a plane was burned when the headphones exploded and caught fire. The woman was relatively okay, but it's never good when a piece of gear catches fire, especially when it's on a plane and especially if it's near your face. With the rise of battery-powered headphones, are in-ear explosions yet another thing to worry about?

First, the details on this exploding headphone: An Australian woman on a flight from Beijing to Melbourne fell asleep while wearing headphones. Two hours into the flight, she was awakened by a loud bang and a burning sensation. She grabbed the headphones and pulled them them off. According to the woman, the headphones "were sparking and had small amounts of fire." Alert flight attendants poured water on the headphones, which wound up as a melted lump on the floor of the plane. The woman's face and hands were burned, and reportedly passengers were "coughing and choking" for the rest of the flight.

In a statement, the Australian Transport Safety Bureau did not identify the brand of the headphones but did surmise that it was the lithium-ion battery in the headphone that caught fire. They issued a warning about the dangers of battery-operated devices in-flight.

None of this comes as news to Samsung. As you will recall, Samsung was the latest company caught in the firestorm of self-igniting electronics. The launch of the Samsung Galaxy Note 7, one of the most important product in the company's lineup, turned into a debacle when reports surfaced that the device was going up in smoke. Eventually, the Galaxy Note 7 was barred by many airlines, and the company was forced to recall the device, to the tune of about $17 billion in lost revenue.

The problem with the Galaxy Note 7 was its lithium-ion battery, a type of rechargeable battery technology that is widely used because of its high energy density, low self-discharge, and small memory effect. However, the design of lithium-ion batteries makes them susceptible to thermal runaway which can, in rare cases, lead to combustion. Lithium-ion batteries contain a pressurized flammable liquid electrolyte. Short-circuiting can cause a battery cell to overheat and possibly in turn overheat adjacent cells causing the entire battery to ignite To help avoid hazard, battery packs contain safety features such as circuitry that disconnects the battery when its voltage is outside a safe operating range.

All lithium-ion batteries have risks. Manufacturers must employ testing standards that are far more rigorous than with other types of batteries. One might casually counsel steering clear of sketchy battery companies, but in fact the battery suppliers for Samsung's Galaxy Note 7 were all top notch companies (one of them was a Samsung subsidiary and another was the main battery supplier for iPhones). Even the best battery manufacturers cannot make perfect lithium-ion batteries.

So, should we be worried by lithium-ion-powered headphones and other devices? Not really. The odds of an explosion or fire are extremely low, perhaps one in a million. Still, safety is always a concern. Because risks are inherent in any lithium-ion battery, consumers are best advised to understand the risk, adhere to any product recalls, and stay informed. To that end, consider articles on lithium-ion battery safety by Consumer Reports and Underwriters Laboratories.