STEVE INSKEEP, HOST:
Southwest Airlines has a new rule for passengers. The airline requires passengers to keep battery packs and other portable charging devices visible when using them in flight. Southwest says this is a safety measure so crew members can more easily respond to possible fires.
ANTHONY BRICKHOUSE: It could be a laptop, it could be a cellphone. It could be a power pack that we all typically use when we're traveling. So anything literally powered by a lithium ion battery could be problematic.
INSKEEP: Anthony Brickhouse is an aerospace safety consultant.
BRICKHOUSE: Sometimes those batteries can overheat or experience something that we call thermal runaway, which could result in them catching on fire.
INSKEEP: We had so many questions about this policy, one of them being how easily can it be enforced? If the thing is out of sight, it's out of sight. But in any case, there's the other question, which is how big a risk are lithium batteries on planes? Well, since the start of this year, there have been 22 verified incidents of those batteries catching fire or smoking or overheating, according to the FAA. David Wroth is director of the Thermal Runaway Incident Program at UL Standards & Engagement, a nonprofit working on safety.
DAVID WROTH: But the other side of that is there are 180,000 airline flights each week. So it is a rare situation, but having a fire at 35,000 feet is very scary.
INSKEEP: Wroth says Southwest's new policy means that help can come faster if something goes wrong. Some good news is there are people working to make batteries in our devices less of a risk. People like Kelsey Hatzell, who's a mechanical and aerospace engineer at Princeton.
KELSEY HATZELL: The Holy Grail of materials for a battery is lithium metal anode. So that's where I think the batteries are going. Lithium metal or silicon anodes are going to be really game changing for increasing the energy density of a battery and eliminating the need to carry so many extra charging devices around because then your battery will last longer.
INSKEEP: I hope she gets a real charge out of her work. It's energizing.
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