What are the dangers of lithium ion batteries on a plane?

Rechargeable lithium ion batteries are an indispensable part of modern life.

They're powerful, compact in terms of their energy output, low maintenance, they can be recharged hundreds of times and they're relatively environmentally friendly. Without them our laptops, phones, tablets, cameras and hundreds of other devices would grind to a halt.

However they're also a potential fire hazard. A short circuit can result in high temperatures and combustion, as underlined by the recent problems experienced by Samsung Galaxy's G7 phone.

Concern around this issue has led the International Air Transport Association to impose restrictions on the power rating, number and type of lithium ion batteries that can be carried on aircraft.

The group most likely to be affected by this restriction is photographers and cinematographers, who might carry several backup lithium ion batteries.

Most airlines will permit lithium ion batteries up to 160 watt hours to be carried as checked luggage provided they are installed correctly in the equipment they're intended for with the on/off switch protected to prevent accidental activation.

Generally, spare batteries not installed in equipment or devices can only be taken on board as carry-ons, either in the original packaging or each battery placed inside its own plastic bag.

Cathay Pacific allows up to 20 spare batteries under 100 watt-hours in carry-ons, and only two spare batteries in the range 100-160 watt-hours.

Other airlines may differ in the number of lithium ion batteries that a passenger can carry. If you're flying with spare lithium-ion batteries, check under "baggage information" on your airline's website.