Lithium batteries do pose a safety risk

Question: I understand that lithium batteries are permitted only in carry-on luggage. What if someone accidentally left one in their checked luggage? Are checked bags scanned for these lithium batteries before being loaded?

— submitted by reader Dan K., Va.

Answer: The bags are scanned for security, not specifically for lithium batteries. If you leave a lithium battery in your bag, it will travel with you.

Lithium batteries provide a lot of power for their weight; consequently, they are the battery used in most electronic devices.

But lithium batteries can spontaneously overheat and have what’s called a thermal runaway, in which excessive heat causes more heat and potentially causes a device to explode. This is not common but does happen.

It is safer for the battery to be in the cabin so that if a thermal runaway occurs, the cabin crew can deal with it. This is why some airlines have recently instituted bans on so-called “smart bags” in checked luggage, as they contain lithium-ion batteries.

Lithium batteries present a risk. We are going to have to monitor them very carefully to maintain the necessary level of safety. Keeping them out of the cargo holds is a good idea.