If you keep a Lithium Ion battery powered device long enough, you may notice it start to grow a bit. It may even happen if you haven’t had the device for very long. You may wake up one day and notice that the case on your phone is a more snug than it used to be, or that the trackpad on your laptop doesn’t have that “give” when you tap it. Much like a pair of jeans or your pet’s waistline, electronics that start to show more mass than usual is a sign that something may be going on with it health-wise.
The first suspect? The beautiful battery that is powering it. Lithium-ion (Li-ion) batteries are great things; they have high capacities, can handle a lot of recharge/discharge cycles, and they don’t have “memory” effect like their nickel-cadmium predecessors. The downside to all that greatness is that Lithium is inherently a VERY unstable element.
You see, Lithium and Oxygen aren’t on good speaking terms, so to speak (see what I did there?). Oxygen is the popular jock that everyone loves and talks about, with all of that “I give life to everything on this planet” bravado, and Lithium is the quiet kid that is sick and tired of hearing about it. When they are in the same room, they have to be kept apart (or at the very least, heavily controlled) by other elements or physical barriers. If they aren’t separated, they go all “Gangs of New York” with each other, which is either entertaining to watch or just plain catastrophic, depending on what happens to be near them.
Remember those Samsung Note 7 phones exploding and catching fire? That’s what happens when Oxygen goes all “COME AT ME, BRO” and Lithium calls that bluff. They break through their physical and chemical barriers.
All batteries degrade over time; it’s a fact of life when it comes to repeated charging and discharging and the environmental factors that go along with toting them in a pocket or bag. Batteries have numerous built-in safeguards that prevent catastrophic failures resulting in fires, like circuitry that will prevent the battery from accepting electrical current and/or warning messages with more advanced devices like computers and phones. When a battery begins to swell, that is a surefire sign that those preliminary safety measures have failed and Oxygen and Lithium are about to meet in the middle.
Battery swelling is the last safeguard, and allows for the battery to fail safely by trapping the flammable gasses and compounds that are released as the battery degrades and reacts. All of this is not to say that EVERY battery with swelling will explode or catch fire; in fact, most do not. Those safety features do their job properly most of the time, and only fail horribly when either a defect is present in the battery, or the person using it ignores the warning signs and mishandles it.
There may be someone out there right now saying, “But Jordan!! The battery in the phone/laptop/surgically-implanted-iPad-in-my-hand that I am using to read this is swollen! What do I do?”. Turn it off. Remove the battery. Do not pass go, do not collect $200. Take the battery to a company that disposes of Li-ion batteries, and let them know that it is swollen. There are TONS of places that accept batteries to be recycled for free, and for the love of Golden Retriever puppies, DON’T THROW IT IN THE TRASH. You don’t want to be responsible for a fire or a waste handler losing a finger because you were lazy.