For most AA batteries, ‘exploding’ usually means a loud ‘pop’ sound and ejection of corrosive materials. When alkaline, NiMH and even lithium AA batteries rupture, the force and heat of the explosion isn’t anywhere near that of, say, an explosive li-ion failure - although it’s still potentially hazardous to users, and the causes should be investigated when safe to do so, along with contacting the manufacturer or supplier.
If you’re ever faced with a badly leaking, ruptured or exploded alkaline AA battery, the best procedure is to immediately and carefully wash all traces of ejected material off your skin. Once this has been done, any traces of this remaining lye material should be neutralised with a household acid such as vinegar or lemon juice - but only do so after removing as much material as possible with water, otherwise, an exothermic chemical reaction can occur, generating more heat.
If any material has made direct contact with your eyes, wash them thoroughly and seek medical advice. Once you’ve taken care of yourself, it’s important to clean any leaked material off components and contacts in the battery enclosure, as it can damage devices irreparably if left to degrade the metals. Again, vinegar or lemon juice on a cotton bud will be effective here, as will careful scraping with a flat screwdriver for any stubborn residue.
Are AA batteries allowed on planes?
Yes, AA batteries are allowed on planes, although there are some caveats and best practices you should be aware of:
- Dry-cell batteries, which include alkaline, lithium and NiMH rechargeable AA batteries, are allowed in carry-on luggage (both inside devices and as spares)
- With the exception of spare lithium AA batteries, which must only be carried on board, all of the above are also allowed in checked baggage
- However, it’s generally not recommended to put spare batteries in checked baggage if you can possibly avoid it - it might seem counterintuitive, but in the unlikely event of a problem, you’re far safer having them with you in your carry-on luggage where they can be accessed by staff trained to deal with such issues
- All spare batteries carried outside devices should be packed in a protective plastic case, individual plastic bags, or at the very least have their contacts taped over for the duration of air travel
- Never carry loose batteries in bags containing other metal objects (including coins, paper clips, zips etc), as this can cause them to short-circuit and become dangerously hot
- Consult your airline for advice regarding any spare rechargeable Li-ion batteries - these are generally allowed as carry-on, but are often subject to strict size limits
How do you store AA batteries?
Many AA batteries today boast impressively long shelf-lives, which is especially useful given that you can often enjoy considerable discounts when buying in bulk or larger multipacks. However, achieving optimal shelf-life for most AA cells depends on proper care and storage.
Tips to be mindful of when considering how to store AA batteries long-term include:
- Keep them out of the reach of children
- Ensure they’re stored in a cool and dry environment (room temperature or below)
- Where possible, keep them in their original packaging until ready for use - this not only helps to protect unused cells, but also differentiates them from older or partially drained units
- Don’t store batteries inside devices if you’re not going to be using them for a long time
- If you’re storing a mixture of brand new and partially used batteries, keep them separate and clearly labelled
- Make sure they’re unable to short circuit through direct contact with any other metal items - use a plastic battery storage box, individual plastic bags, or put tape over the terminals
- Periodically test and top-up rechargeable AA batteries, if they’re going to be stored for a long time, as letting them fully discharge in storage, can seriously deplete their capacity
- Never disassemble, puncture, crush or burn batteries of any kind
- Never store rechargeable batteries inside a charger, and never attempt to recharge a battery that’s not designed to do so
Why do AA batteries leak?
Batteries eventually leaking or corroding is a relatively common occurrence, especially familiar with alkaline AA cells if they’re left unattended for long enough. In short, the reason alkaline batteries leak is that they’re continually self-discharging in tiny increments, even when not in use.
Because the discharging process in alkaline batteries creates small amounts of hydrogen gas, pressure gradually builds within the sealed casing of the battery, and in time a small amount of material from inside the cell will often be ejected under this mounting pressure. This material is usually corrosive and should be removed from the skin immediately, then cleaned away from electrical components as soon as possible after that.
The best way to avoid leakage is to regularly replace older batteries, take note of the battery storage best practices outlined in the section above, and to switch to lithium or rechargeable cells for long-term storage if you only need to power a device very occasionally.