The chances that you are carrying lithium-ion batteries with you when flying are very high. They're everywhere, from mobile phones to laptops or cameras. 

Although very safe, they've been known to have created issues in the past, which is why airlines forbid you to check any in cargo.

Look at what happened during a recent KLM flight:

Battery on fire. (image credit:  @Accone)

Battery on fire. (image credit: @Accone)

It caught fire!

Whilst this remains an extremely rare occurrence, what do the airlines say specifically? Here's KLM's take:

Loose lithium batteries, such as rechargeable lithium batteries and AA lithium batteries for laptops and DVD players, may only be carried in hand baggage. Each spare battery must be packed in the original packaging. If you no longer have this packaging, you must cover the battery contact points with tape to insulate them and pack each battery in a separate plastic bag.

We don't have control of the batteries installed within our personal electronic devices but the rule on the extra ones (a second camera battery or a smartphone external battery for instance) is clear: we should put them in their original packaging or tape the contact points whilst placing each one in a separate plastic bag.

Do you do that? As Alex said during our last podcast episode, anybody who says they do is probably a liar.

And yet, look at the video:

No wonder they are now forbidden in cargo (thus also heavily restricted by postal services by air).

On a related note, similar batteries were the ones that were responsible for the fires that grounded the 787 Dreamliners. 

✈︎ LISTEN: A battery causes fire during a KLM flight (51:38)