Virgin Australia says it is considering changes to its rules around lithium batteries after a fire on a flight from Sydney was thought to have been caused by a power bank in a passenger’s carry-on luggage.
Australia’s Civil Aviation Safety Authority (Casa) has said the average passenger travels with at least four rechargeable lithium battery devices, which can be contained in smartphones, laptops and portable power banks.
If you’re wondering what the rules are, and why lithium-ion batteries are considered a risk on flights, here’s a quick overview.
Can I bring a power bank on a plane?
Yes. But rules vary, so you should check the airline’s restrictions before you fly.
Generally, laptops and cameras can be packed in checked luggage as long as they are completely switched off, according to Casa.
But spare batteries and power banks should only go into carry-on baggage because batteries and power banks can short circuit, overheat and catch fire during a flight.
Lithium-ion batteries that exceed 160Wh are not permitted at all, unless they are used for mobility aids.
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Smart bags with power banks or lithium-ion batteries are allowed as long as the battery can be removed before check-in and carried in a passenger’s cabin baggage.
Virgin Australia says any spare or loose batteries, including power banks, must be in carry-on baggage only and must be protected by placing them in their original retail packaging, or placing each battery in a separate plastic bag or protective pouch, or taping over exposed terminals.
Qantas says passengers travelling with power banks, including Apple AirPod cases, and spare or loose batteries, must only take them in carry-on baggage.
The airline says it does not recommend the use or charging of power banks onboard due to safety.
Can I take a power bank on a plane overseas?
Several international airlines have banned the use of power banks on board, including Thai Airways, South Korean Airlines, EVA Air, Cathay Pacific, China Airlines, Singapore Airlines and its budget subsidiary, Scoot.
If you’re flying with an international carrier, you should check its rules before your flight.
Generally, passengers are required to pack their power banks in their carry-on luggage. But whether they can be used on the plane depends on the specific airline.
Are lithium battery fires more likely to happen on planes?
Not necessarily. Prof Neeraj Sharma, a battery expert at the University of New South Wales, says lithium-ion batteries can have 20 different components, some of which are liquids, making them more volatile than other, solid parts such as the electrodes or casing.
Applying pressure to a lithium-ion battery can lead to “thermal runaway” – an uncontrollable increase in temperature – but a battery exploding is incredibly rare.
Sharma says airlines still instruct people to carry batteries in their hand luggage as a way to mitigate risk, because there is a minimal pressure difference in a plane cabin compared with the baggage hold.
Sharma says power banks and other lithium-ion battery devices that aren’t as well regulated as mobile phones or laptops – such as e-scooters and vapes – pose more of a risk and may have lower quality batteries.
Prof Amanda Ellis, the head of the University of Melbourne’s School of Chemical & Biomedical Engineering, says lithium battery fires aren’t more likely on planes.
She says airline cabin pressure wouldn’t get to the batteries because they are covered by “multiple layers of casing” but any enclosed environment makes fires particularly dangerous, especially as a plane can’t be evacuated mid-air.
“They give off a very toxic gas and in a confined space that’s not ideal,” she says.
Ellis says lithium-ion battery fires are difficult to extinguish because often the lithium metal catches on fire, along with all the casing and the plastic – high-energy materials that can burn for much longer.
“You wouldn’t want to put water on a lithium fire. And that’s the first thing people [on a plane] might think of doing.”
Why do lithium-ion batteries catch on fire?
The batteries contain lithium ions suspended in an electrolyte solution. The ions flow through the electrolyte, travelling back and forth between two electrodes as the battery charges and discharges.
Ellis says a common cause is from people overcharging their batteries, so they overheat, which results in thermal runaway. If there’s too much energy in the battery, it can crack, causing the highly flammable electrolyte inside it to burst into flames when exposed to air.
She says phones and other, more sophisticated lithium battery-powered devices have an internal “trickle system” which slowly adds current into the battery to prevent overcharging.
But cheaper power banks typically don’t have this safeguard, Ellis says, making them more of a risk.
“Never charge your power bank overnight,” she says. “Never charge it more than it has to be charged. In a way you’ve got to watch the power bank for when the light goes from red to green, and unplug it.”
Ellis says that, overall, batteries are very safe if used appropriately and in the right conditions, and people shouldn’t be worried about flying because of them.