Why lithium batteries explode
Lithium batteries have completely revolutionized the way we build and use our gadgets. They’re small and light, but pack a big energy wallop. They can also spontaneously explode, like when this this poor chap’s e-cigarette set his pants on fire. What’s going on here?
What are lithium batteries?
Lithium is the lightest metal. It packs the highest energy density of all metals. This makes it very useful for building batteries.
To build a battery, you “plasticize” lithium in a polymer electrolyte. Unlike a traditional “can” battery, this process allows the pack to be made into any shape or size you need. A typical cell phone battery is only as thick as a pair of credit cards, but contains twice the capacity and nearly three times the voltage of a AA.
So why do they blow up?
Lithium reacts violently when exposed to oxygen. You probably saw this demonstrated in high schools science class. If not, there are tons of great videos on YouTube.
If a lithium battery ruptures, it will spontaneously catch fire the second it’s exposed to air or water.
There are lots of ways to damage a battery. Physically puncturing it is definitely a bad idea. However, they can also be damaged by overheating, over-charging, or a short circuit. In this case, the contents expand in the pack causing it to “puff”and eventually burst like a balloon.
How do we prevent this from happening?
Physical damage is easy enough prevent through the use of hard cases surrounding the soft battery.
Over charging and shorting is prevented through the use of charge protection circuitry. A microchip monitors the pack while it is being topped up. Once the pack is full, or if any anomalies are detected, the charger immediately shuts off the power.
So if there’s protection devices, why are batteries still exploding?
Abuse by the end user is probably the leading cause. If you’re knocking the battery around or using the wrong charger, it can blow up.
However, faulty batteries and chargers are a problem. While high end devices certainly aren’t immune, this issue is mostly seen in low end products.
When you’re trying to produce a product as cheap as humanly possible, concern for safety and quality tends to gets thrown out the window. Many no-name overseas factories are not afraid to use rejected or low quality batteries. Nor are they afraid to bundle them with shoddy chargers that may even lack the proper protection circuitry.
A lot of Chinese knock-off goods, from e-cigarettes to hover boards, come from factories like this. They’re often sold online to skirt around the local authorities, but there’s little in the way of regulation keeping them out of the shops.
Should I be worried?
Given the billions of devices that use lithium batteries every day with no issue, the risk is statistically insignificant. As long as you treat you phone, vape, or whatever with care, you’re fine. However, there are still a few precautions you can take to protect yourself from faulty goods.
Only buy your devices from reputable brands, and only from reputable retailers. That deal on eBay that looks too good to be true, probably is. Also check to ensure your new device bears the Underwriters logo, or that of a similar safety standard organization in your country.
If you notice your device’s battery is puffing or getting abnormally hot, discontinue using it immediately and contact the shop you bought it from or the manufacturer. They should be able to replace it for you.
Photo by Mpt-matthew via Wikipedia. Used under CC BY-SA 3.0 license.
