Every few years, exploding phones find a way to dominate the news cycle. And while these accidents are incredibly rare, they are a bit difficult to understand. Why do phones explode? And how do I know my phone won’t explode?
Heat escape caused the phone to explode
Whenever a lithium-ion battery explodes or catches fire, it undergoes a process called thermal runaway. This process can be a little tricky to understand, so we’ll keep things short, sweet, and free of dense scientific jargon.
Lithium-ion batteries contain a ton of lithium-ion cells. Each of these cells has a critical temperature — think of it as the boiling point. When a cell’s critical temperature is reached (due to external heating, overcharging, damage, or poor manufacturing), it enters an exothermic failure. In fact, the cell itself begins to release a ton of heat.
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This starts the process of thermal runaway, which is essentially a positive feedback loop (like when you put a microphone next to a speaker). Once a cell enters exothermic decay and releases heat, its neighboring cells are destined to reach their own critical temperatures. Depending on the speed of this process, the battery may exhale quietly, catch fire, or cause a minor explosion.
Now that we understand the process of thermal runaway, it’s much easier to determine how, when, and why phones explode (among other lithium-ion devices).
However, if your phone or other device has a swollen battery, you need to do something about it right away.
RELATED:What to do if your phone or laptop has a swollen battery
Don’t leave your phone in the car
If you live in a snowy area, you probably know that car batteries work best when they’re a little warm—say, 80 degrees Fahrenheit. You probably also know that too much heat can ruin a battery along with other components in a car. Well, the same goes for phone batteries.
When a Li-ion battery is discharged at high temperatures (whether sitting outdoors or in a car), the cells may become slightly unstable. They may not enter into an exothermic breakdown, but they may permanently short out, deteriorate, or (oddly enough) produce gases such as oxygen and carbon dioxide. These gases can cause the battery to inflate like a balloon, which builds up pressure (energy that can cause an explosion) or disrupts the battery’s structure.
Naturally, this process can be accelerated if the lithium-ion is charged at a high ambient temperature. This is why most phones stop charging or turn off if they get too hot.
However, your phone probably won’t explode after being left in a hot car for a day. And while constant short circuits and pressurization can lead to overheating, these slow forms of mechanical wear usually cause the battery to fail before it has a chance to explode. In addition, phones and lithium-ion batteries have built-in safety features that prevent slow-onset mechanical problems from failing. Just remember that these security features usually result in the death of your phone.
Use reliable or certified chargers
Generally speaking, any charger will work with any device. An old or cheap micro-USB cable will work with new phones, and a new ultra-fast charger will work with older devices. But you should probably stick with reliable chargers from good companies or chargers certified by your phone manufacturer.
Cheap or uncertified chargers (especially crappy wireless chargers) can generate excess heat and damage your phone’s battery. Usually this damage happens over a long period of time and it results in «bubbles» or short circuits in your phone’s battery. Again, this type of slow mechanical damage will almost always break your phone before it can catch fire.
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But don’t worry, a cheap charger won’t «recharge» your phone (although it will undoubtedly cause an explosion). Phones have built-in voltage limiters that prevent overcharging or charging the battery too fast.
Finding the right charger for your phone is surprisingly easy. You can buy a charger directly from your phone’s manufacturer, check charger reviews on Amazon before you buy, or search Google for your phone’s name for «best chargers.» If you have an Apple device, you should also look for MFi-certified chargers, and if you’re shopping for a wireless charger, look for a Qi-certified device.
Do not bend or hit your phone
When a Li-Ion battery is physically damaged, it can short out, build up gases, or flare up in place. If you don’t disassemble your phone or smash it for fun, you don’t have to worry about it. When a phone is dropped, critical components such as the display usually break before the battery is damaged.
Why is this happening? Okay, lithium-ion batteries contain a thin sheet of lithium and a thin sheet of oxygen. The electrolyte solution separates these sheets. When this solution is ruptured or pierced, the layers of lithium and oxygen react, which initiates exothermic destruction and thermal destruction.
In some cases, this can happen when you change your phone’s battery. Breakdown or bending of Li-ion can lead to mechanical failures and if the battery is not working properly during installation, it can catch fire (immediately or over time). Recently, a woman’s iPhone caught fire at an unofficial repair shop, and some Apple Stores caught fire while changing iPhone 6 batteries.
Also, as a side note, don’t stick batteries in for fun. You may be able to avoid a fire or a small explosion, but you cannot avoid the toxic gas released by a burning lithium-ion battery.
Most phone explosions are due to poor manufacturing
While overcharging and overheating sound like dangerous, battery-bursting nightmares, they rarely cause fires or explosions. Slow-forming mechanical failures tend to destroy a battery before it has a chance to enter a thermal runaway, and built-in safety features prevent these failures from getting out of hand.
Instead, the fate of the phone is usually determined during the manufacturing process. If the phone is meant to explode, then there’s nothing you can do about it.
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Lithium-ion batteries contain lithium, an incredibly unstable metal. This instability is good for holding and transmitting electricity, but it can be disastrous if not properly mixed with other metals. Unfortunately, lithium-ion batteries must also contain nickel, cobalt, and graphite. During the manufacturing process, these metals can form deposits on manufacturing equipment, which can then contaminate the inside of a lithium-ion battery and cause chemical instability, short circuits, and explosions.
Poor assembly can also be a problem. Like a skyscraper or a car, lithium-ion batteries are welded from different pieces, and poor welding can create a lot of electrical resistance. This resistance (friction) generates heat which can cause short circuits and mechanical problems within a very short period.
Relax, your phone probably won’t explode
Throughout the entirety of the Galaxy Note 7 between 90 and 100 Note 7s exploded, caught fire or overheated. That’s less than 1% of the 2.5 million Note 7s that Samsung has shipped to stores. Sure, Samsung’s global recall probably kept those numbers from rising, but it’s clear that phone explosions are extremely rare.
However, you should be mindful of exploding phones. Avoid buying phones that are brand new and do a quick Google search before you get a new phone. And while slow-onset mechanical issues rarely cause phone explosions, the risk isn’t worth taking. Do not leave your phone hot, try using reliable or certified chargers and please do not hit or bend the phone.
RELATED:Debunking myths about battery life on mobile phones, tablets and laptops
