It may start with something subtle, like a trackpad that just doesn’t click like it used to, or a laptop that doesn’t quite sit flush to the desk anymore – or it may be something blatantly obvious, like a notebook case that starts to warp and grow like a bag of popcorn in the microwave.
Either way, what you’re dealing with is modern technology’s equivalent of the plague – a swollen lithium-ion battery. Although this may seem like an interesting malfunction, it is actually extremely dangerous. Lithium-ion batteries are volatile and they’re in most of our tech devices today.
In this article, I’ll show you to safely handle swollen battery in your laptop, smartphone, or other high-tech devices.
Why are lithium-ion batteries useful?
Lithium-ion batteries have some major advantages over other battery chemistries. Lithium-ion batteries are very energy-dense, meaning that a large amount of electrical power can be stored in a relatively small and light space.
The batteries have very long cycle durations and shelf life, meaning that they can be charged and discharged many hundreds of times before losing efficiency. They are easy to charge with inexpensive, low-tech battery chargers, and can be charged fairly quickly relative to other battery types. They have low self-discharge rates, meaning that a charged battery can sit for some time between uses without losing significant amounts of power.
There are some disadvantages to this battery chemistry. One disadvantage is that the batteries have the potential to enter a thermal runaway cycle (i.e. they catch fire) if the battery is put under certain kinds of stress. For this reason, any device using a lithium-ion cell must include circuitry that can detect these runaway cycles and shut the battery down.
Lithium-ion batteries are vulnerable under high-temperature conditions, and can’t be charged at high voltages. In cold temperatures, the batteries function just fine, but cannot be rapidly recharged without causing severe damage.
Finally, the thermal hazard that a poorly-built battery represents means that transporting them requires precautions and is subject to numerous regulations.
Despite these disadvantages, the advantages of lithium batteries are such that the technology has become extremely useful, and lithium-ion batteries are used in practically all high-tech applications.
What causes a swollen battery?
There are a number of possible reasons that a lithium-ion battery can swell.
The most common cause is an overcharge of the battery, which causes a chemical reaction between the electrodes and the electrolyte, resulting in the release of heat and gases that expand inside the battery, causing the casing to swell or even to split open.
Swelling can also result from a manufacturer’s defect. Mechanical damage to the battery, such as striking a hard surface and denting the casing, can cause a swelling condition, as can exposure to excessively high temperatures.
Finally, lithium-ion batteries can swell as a result of deep discharge of the cells; usually, lithium-ion batteries are governed by circuitry (sometimes called a battery management system or BMS) that prevents this from happening.
In any event, whatever the primary cause of the swelling, what occurs inside the battery is that too much current is present inside a given cell of the battery. According to an article by Don Sadoway, professor of materials chemistry at MIT in Electronics Weekly : “There are strict limits on how much current can be put through a lithium-ion cell.”
This means that a lithium-ion battery malfunction can happen and when it does it can be catastrophic.
How to avoid a swollen battery
There are a number of things you can do to minimize the risk of battery failure. You can’t completely eliminate the risk because there is always the possibility of a factory defect, but owner mistreatment of the battery is by far the most common cause of a swollen battery.
In addition to preventing battery swelling, these suggestions are also good for optimizing your battery life.
Always use the appropriate power charger. Use only quality chargers from reputable manufacturers, not third-party chargers built by a no-name factory. If you don’t have the original charger that came with a battery, then get a charger with the exact same power output as the original charger. Just because the charging plug fits does NOT mean that it is appropriate for your specific battery configuration!
Don’t leave your device plugged in all the time. This is particularly an issue for laptop users who primarily use their laptop at home. The device sits plugged into the wall all the time, and the battery isn’t given the opportunity to exercise its capacity. For Mac users, the free tool coconutBattery  can help remind you when it’s time to unplug your power cord and let the battery complete a discharge and recharge cycle. Windows users can check out a number of options that offer similar functionality, such as BatteryCare  (free) and BatteryBar Pro  ($8). If this is something you do, check out our article. 
Keep your battery stored in a cool, dry environment. Occasional use in the sun is fine, but don’t store your laptop or smartphone in a hot car, or humid environment.
Replace your battery if it becomes exhausted or damaged. Batteries are consumable products; they’re meant to slowly degrade in performance over time. So if your battery is no longer holding a charge, or if it becomes damaged due to a drop or impact, make sure to replace it, before a catastrophic failure can occur.
How to deal with a swollen battery
If you suspect that your device has a swollen battery, the first step is to exercise caution. Puncturing a battery in any state is incredibly dangerous, but swollen batteries are especially vulnerable to compromise as their casing is already under stress from the built-up gases within. In short, handle any device with a suspected swollen battery with care.
Next, if your device has a user-removable battery, you can try to carefully remove it. Note that the battery’s swollen casing may make removal difficult. If you encounter any unusual resistance to removing the battery, stop and follow the advice below for those with devices containing non-user-removable batteries.
If, however, you are able to successfully remove the swollen battery, place it in a safe, cool container so that it won’t be vulnerable to punctures.
Do not discard the battery in the trash or elsewhere. Doing so can severely injure the health of sanitation workers who may come into contact with the battery, as well as the environment.
Instead, always dispose of batteries — swollen or not — at an authorized battery disposal facility.
Many computer repair locations have the equipment and procedures to safely handle swollen batteries. For example, if you have an Apple MacBook Pro, take the battery to your nearest Apple Store . Other electronics retailers, such as Best Buy , also offer recycling and disposal services. It’s best to call ahead and alert the retailer that you’re bringing a swollen lithium-ion battery in so they can be prepared to handle it.
If you can’t find a suitable location to dispose of your battery, contact your local government for instructions.
If your device does not have a user-replaceable battery don’t try to remove it yourself. Simply take the entire device to one of the locations mentioned above for assistance.
Note, however, that until your swollen battery is replaced, you shouldn’t connect your device to power or use it. Swollen batteries can explode if not properly dealt with, so you don’t want to take any actions that may hasten the arrival of this unpleasant event.
Above all else, be safe. Don’t try to puncture the battery, don’t leave it in a hot car or a location where it could be picked up by children or pets, and don’t ignore it. Your laptop or smartphone will likely continue to work with a swollen battery, at least for a little while. But ignoring the problem and continuing to use the battery will only increase the risk of a puncture or explosion, which could result in devastating injuries. Battery leaks and explosions are rare, to be sure, but you don’t want to test the odds.
What to Do if Your Battery Starts Smoking
In what is often referred to as a “battery event,” a swollen lithium-ion battery may start to smoke or even catch fire. You may also notice a “hissing” sound without seeing any visible signs of flames. If you find yourself in a situation where this happens, it is important to understand how to handle it.
DO NOT use water to extinguish the battery, this can release excess hydrogen making it even more volatile. Instead, submerge the battery in sand or even kitty litter to extinguish the flames or control the situation. Using a Class B fire extinguisher is ideal, but if you don’t have one of those handy, sand or litter will do the trick.
If the battery is smoking; it releases gas into the air, it’s also a good idea to increase ventilation to the room such as open windows while ensuring that nothing else will catch fire.