Why Do Phones Explode? (And How to Prevent It)

A woman gasping as her phone ignites
HomeArt / Shutterstock

Every few years, phones explode find ways to dominate the information cycle. And while these accidents are incredibly rare, they are a bit difficult to understand. Why are phones exploding? And how can I know that my phone will not explode?

Thermal leak causes phone explosion

Whenever a Li-ion battery explodes or catches fire, it undergoes a process called thermal runaway. This process can be a bit difficult to understand, so we will keep things short, enjoyable and free from dense scientific jargon.

Lithium-ion batteries contain a ton of Li-ion cells. Each of these cells has a critical temperature – consider it a boiling point. When the critical temperature of a cell is reached (due to external heat, overcharging, damage or poor manufacturing), it goes into exothermic failure. Basically, the cell itself starts to release a ton of heat.

A diagram that explains the thermal runaway
Wikipedia

This triggers the process of thermal runaway, which essentially consists of a positive feedback loop (such as when you place a microphone next to a speaker). Once a cell enters into exothermic decomposition and releases heat, the neighboring cells are intended to reach their own critical temperatures. Depending on the speed of this process, a battery may extinguish, ignite, or create a small explosion.

Now that we understand the process of thermal runaway, it is much easier to determine how, when and why phones (among other Li-ion devices) explode.

If your phone or other device has a swollen batteryHowever, you will want to do something about it now.

RELATED: What to do when your phone or laptop has an inflated battery

Do not leave your phone in the car

If you live in a snow-covered area, you probably know that car batteries work best when they are a bit warm, for example at 80 degrees Fahrenheit. You probably also know that too much heat can destroy a battery, as well as other components of a car. The same goes for phone batteries.

When a Li-ion battery discharges at high temperatures (sitting outside or in a car), its cells can become a little unstable. They can not enter into exothermic decomposition, but they can permanently cause a short circuit, deteriorate or (oddly enough) produce gases such as oxygen and carbon dioxide. These gases can cause the battery to swell like a balloon, creating pressure (energy that can cause an explosion) or compromising the battery structure.

Of course, this process can accelerate if a Li-ion is being charged at a high external temperature. That's why most phones stop the charging process or turn off if they become too hot.

That said, your phone will probably not explain after being left in a hot car for a day. And if permanent short-circuits and pressure buildup can cause thermal runaway, these forms of slow mechanical deterioration usually cause a battery to break before it can explode. In addition, phones and Li-ion batteries have built-in security features that prevent mechanical problems of slow formation from becoming uncontrollable. Do not forget that these security features usually result in the death of your phone.

Use reliable or certified chargers

In general, No matter which charger will work with any device. An old or cheap micro-USB cable will work with the new phones and a brand new super-fast charger will work with older devices. But you should probably stick with reliable chargers from good companies or chargers certified by the manufacturer of your phone.

Cheap or non-certified chargers (especially poor quality wireless chargers) can generate excessive heat and damage the phone's battery. Usually, this damage occurs over a long period of time and can cause "bubbles" or short circuits in your phone's battery. Again, this type of slow-acting mechanical damage will almost always damage your phone before it can ignite.

An iPhone charging in a car
Casezy Idea / Shutterstock

But do not worry, a cheap charger will not "overload" your phone (although it would definitely cause an explosion). The phones have built-in voltage limiters that prevent overcharging or "too fast" charges for the battery.

Finding the right charger for your phone is surprisingly easy. You can buy a charger directly from the manufacturer of your phone, consult Amazon reviews before you buy it or perform a Google search on your phone's name with the words "best chargers". If you have an Apple device, you should also watch for MFi certified chargers, and if you buy a wireless charger, look for a Qi certified device.

Do not bend and do not attack your phone

When a Li-ion battery is physically damaged, it can cause a short circuit, a buildup of gas or an explosion of flames. Unless you disassemble your phone or break it for fun, it's not a problem you need to worry about. When you drop a phone, important components such as the screen usually break before the battery is damaged.

Why does this happen? Li-ion batteries contain a thin layer of lithium and a thin layer of oxygen. An electrolyte solution separates these leaves. When this solution is broken or punctured, the lithium and oxygen layers react, triggering exothermic decomposition and thermal runaway.

In some cases, this can happen when replacing the phone's battery. Perforation or bending of a Li-ion can cause mechanical breakdowns. If a battery is not handled properly during installation, it may catch fire (immediately or in time). Recently, a woman's iPhone caught fire after having the battery replaced in an unofficial repair shop, and some Apple stores have fire treatment by replacing the batteries of the iPhone 6.

In addition, do not stab the batteries for fun. You may be able to avoid a fire or a minor explosion, but you will not be able to avoid the toxic gas released by a burning lithium-ion battery.

Most phone explosions are due to poor manufacturing

Overloading and overheating are like dangerous nightmares that blow up the battery, but they rarely cause fires or explosions. Slow mechanical breakdowns tend to break a battery before it can enter a thermal runaway, and the built-in security features prevent these failures from becoming uncontrollable.

Instead, the fate of a phone is usually determined during the manufacturing process. If a phone is going to explode, you can not do anything about it.

A machine assembling a smartphone
asharkyu / shutterstock

Li-ion batteries contain lithium, an incredibly unstable metal. This instability is ideal for storing and transferring electricity, but it can be disastrous if mixed poorly with other metals. Unfortunately, Li-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 bowels of a Li-ion battery and cause chemical instability, short circuits, and explosions.

A bad assembly can also be a problem. Like a skyscraper or a car, Li-ion batteries are welded together, from various elements, and poor soldering can create a lot of electrical resistance. This resistance (friction) generates heat, which can cause short circuits and mechanical problems over a very short period of time.

Relax, your phone is not likely to explode

Throughout the Galaxy Note 7 controversy, between 90 and 100 Note 7s exploded, caught fire or overheated. That's less than 1% of the 2.5 million Note 7 tickets delivered to stores by Samsung. Of course, Samsung's global recall probably prevented these numbers from rising, but it is clear that phone explosions are extremely rare.

That said, you should always keep in mind the explosion of phones. Avoid buying new phones and do a quick Google search before getting a new phone. And although slow-moving mechanical problems rarely lead to phone bursts, it's not a risk to take. Do not leave your phone in hot caTry to use reliable or certified chargers, and do not bend or stab your phone.

RELATED: Demystify the myths about battery life for mobile phones, tablets and laptops

sources: Natural Communications / PMC, Battery University, Battery power, Michigan Engineering

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