Some of the gadgets powered by lithium-ion batteries which you should take into the aircraft cabin with you and not pack away in your suitcase in the hold Some of the gadgets powered by lithium-ion batteries which you should take into the aircraft cabin with you and not pack away in your suitcase in the hold

Lithium-ion batteries are classed as dangerous goods when it comes to transporting them by air.

This means they cannot be shipped in the cargo holds of passenger aircraft.

The fear is that if they catch fire they will go into what is known as thermal runaway and the cargo holds of planes are simply not designed to deal with such a fierce blaze.  The fires are often caused by faulty lithium-ion batteries inside electronic devices ranging from mobile phones to laptops carried on board by passengers.

During thermal runaway one cell overheating in a battery can produce enough heat – up to 900°C (1652°F) – to cause adjacent cells to overheat. This can cause a lithium battery fire to flare repeatedly. Incidents of thermal runaway are on the rise.

It means passengers should always pack their lithium-ion batteries in bags they take into the aircraft cabin so if there is a problem the flight crew is trained to deal with it.

This means that spare lithium-ion batteries as well as external battery packs are prohibited in checked luggage along with e-cigs and vaporizers and should be kept with the passenger in the cabin. Spare batteries should be protected from short circuiting with terminal caps or tape and never put in pockets where they could come into contact with change, keys and other conductors, causing terminals to be bridged.

Airlines now publish strict rules for transporting lithium-ion batteries on their websites and the responsibility is on passengers to always check them before travelling. They are often similar to these from British Airways:

“You can take with you for your own personal use portable electronic devices that contain lithium batteries such as a laptop, tablet, smart phone, camera and music player.

Please always ensure that you:

Pack all battery-powered devices to prevent accidental activation.

Protect spare batteries from short circuit and damage by keeping them in their original packaging (if possible), in a protective case or a strong plastic bag, or by placing electrical tape over the terminals.

Don't take any damaged batteries or equipment with you.

Important note: If your hand baggage is checked in or removed at the gate and placed in the hold you must remove all spare batteries and power banks and carry them with you in the cabin."

Lynn McGuigan, cargo safety section technical officer at United Nations agency the International Civil Aviation Organisation (ICAO), told online aviation news organisation Aviation Week: “Up to a few years ago li-ion batteries by themselves (in bulk) were permitted to be carried in the holds of passenger aircraft.”

Katherine Rooney, chief of the Cargo Safety Section, added: “There have been instances where batteries that have not been abused have still gone into thermal runaway and we have to assume they were incorrectly manufactured.”

The Federal Aviation Administration (FAA) added: “The U.S. Department of Transportation (DOT) supports the ICAO Council’s decision to prohibit the carriage of lithium-ion batteries as cargo aboard passenger aircraft until safer methods of transport are developed. The DOT and the FAA agree this is a necessary action to protect passengers, crews and aircraft from the risk to aviation safety. In addition, the FAA recommends that passengers safely pack their spare lithium batteries in their carry-on bags.”

* Specially-designed fire containment bags called AvSax which can deal with fires in personal electronic devices are now carried on planes operated by 65 airline companies across the world – including some of the biggest and best-known.

AvSax  – which won the Queen’s Award for Enterprise this year - has been used 28 times to deal with emergencies since the start of 2017.