SCOTT SIMON, HOST:

One of the hottest gifts of the season is a little too hot, hot enough to catch fire. Hoverboards have been burning up because of problems with their lithium-ion batteries. And lithium-ion batteries are in a lot of things these days from smartphones to laptops to Tesla automobiles to Boeing 787s. Jay Whitacre is a professor of materials science and engineering at Carnegie Mellon University. He's joins us from WQED in Pittsburgh. Thanks so much for being with us.

JAY WHITACRE: Thank you very much.

SIMON: So are all of these batteries dangerous?

WHITACRE: No. I mean, in principle all batteries do contain - lithium-ion batteries do contain a flammable electrolyte that will burn if it gets hot enough. But most of them, the vast majority of them, are made safely and as long as they're used properly, that is, they're not overcharged or physically abused to the point where you rupture their package, they're OK. But a very small fraction have internal defects that can lead to the kind of problems we're seeing right now in the marketplace.

SIMON: Would you hazard a guess, Professor, as to why hoverboards seem to be - in particular, maybe seem to be having these problems?

WHITACRE: We have a confluence of at least two things. One is there's a lot of companies making these right now and I think a lot of them are using second-tier battery sources which are going to have probably a higher rate of defects, number one. And number two, these things have more lithium-ion batteries in them than most things because they're used to move you around. It takes more batteries to get the power and energy to do that. And as such, there's just more energy in a small space, and so if something does go wrong, it's a bit more catastrophic.

SIMON: Are there any precautions people realistically can take?

WHITACRE: There's a sense that if you pay more for one of these it may have better batteries in it. When I say better, I mean from a tier-one supplier like LG Chem or Samsung or someone else like that. And I have not verified that. If that was true, that would help. Another precaution would be, especially early on, don't charge or use this indoors because you could seriously have an issue with a household fire or something like that.

SIMON: You mean the hoverboard.

WHITACRE: The hoverboard themselves, yeah. In general...

SIMON: But there's other stuff like...

WHITACRE: Laptops. Yeah, well, that's a great point but these have a fewer numbers of cells inside them, a few - less energy in general. And most of these, you know, the Apples, the computer suppliers that we typically buy from the United States usually have top quality batteries inside them that have a lower frequency of this kind of issue, although you will still see it. Sony had a real problem in 2006. There were a lot of failures in a major battery recall. And they learned a lot from that process. So even the big boys can have this kind of thing once in a while.

SIMON: How do you put out a fire like this, a lithium-ion fire?

WHITACRE: The first thing you want to do is isolate the thing that's on fire. Put it in a nonflammable container. If you had a metal garbage can, for example, you would do that. If you could completely submerge it in something like water or something else that would - that's going to completely squelch the flame, that would be another thing to do.

SIMON: So put your laptop in a full bathtub if something happens?

WHITACRE: Sit it in a bathtub that's full or just put it in the bathtub when it's empty and contain where the fire is. No, seriously, these are - they burn very hot and very fast.

SIMON: You know, interviewing you, I suddenly wonder should we - should we be taking laptops and tablets on airplanes?

WHITACRE: Yes, I think it's impractical for us to say you shouldn't do that. It would be - there'd be, I think, a major mutiny if that was asked of the public in the first place. But more importantly, these are - the frequency of this issue, especially in laptops and cellphones, is very, very low. And if it happens with somebody who can do something about it, usually even on an airplane you can contain it and it will maybe force a landing but not - certainly not down the airplane. Both the U.N. and the, you know, the North American Transportation Authority have been very focused on increasing the scrutiny on lithium-ion battery air shipment and making the rules more stringent and, I think, for good reason. If it's in an unmanned cargo hold where there's lots of cells next to each other and something goes wrong, it could be a real problem.

SIMON: Jay Whitacre, at Carnegie Mellon University, thanks so much for being with us.

WHITACRE: Thank you. It's a real pleasure.