Exploding Lithium-Ion Batteries Are Rare: Here’s Why
Have you heard stories of lithium-ion (Li-ion) batteries exploding? Every now and again the news outlets will report on an exploding e-cigarette or hoverboard battery, only to then begin a frenzy of follow-up stories that can last for weeks. By all accounts it would seem as though these batteries are exploding just about every day. They are not. Exploding lithium-ion batteries are rare.
Government estimates suggest that only one in every 10 million lithium-ion batteries fail. That may not have been the case when Li-ion batteries were first introduced in the early 1990s, but a lot has changed over the last 30 years. Today’s Li-ion batteries are extremely safe.
When Li-ion Batteries Overheat
Virtually every instance of a Li-ion battery exploding or catching fire is the result of overheating. The batteries produce too much heat, resulting in hot spots that eventually lead to catastrophic failure. Prevent a Li-ion battery from overheating and you will pretty much mitigate any risk of fire or explosion.
Pale Blue Earth, the most popular USB rechargeable battery company, explains that Li-ion batteries are smart batteries. They are smart in the sense that they are equipped with on-board computer chips that regulate both charging and discharge. The computer chips are designed to prevent overheating and hot spots.
Preventing Thermal Runaway
The challenge with Li-ion batteries is that they can overheat when either under- or overcharged. It boils down to something known as thermal runaway. Thermal runaway occurs when lithium builds up on the anode (negative electrode). This build up causes a chemical reaction that leads to hot spots.
Note that excess lithium buildup can occur due to excessive discharge or overcharging. A battery discharged below about 5% can be problematic, just like a battery charged in excess of 100%. Thus, the need for some sort of regulator – in this case, the computer chip.
Chips are programmed to monitor charge level. For example, your laptop might warn you when your battery level is under 5%. Truth be told, the power level in the battery is not actually that low. The warning is telling you that your battery is quickly approaching the need to be recharged. Its on-board chip will shut your device off to prevent the battery from being discharged below 5%.
Forcing your device to shut down is the chip’s way of preventing your laptop battery from overheating. Likewise, that same chip cuts off power to the battery once it is fully recharged. This prevents overheating once again.
Exploding Batteries Are Cheap Batteries
All of this is to say that lithium-ion batteries that do explode are, more often than not, cheap batteries. Their computer chips are either poor quality or not installed correctly. The cheaper the battery, the greater the risk.
It is worth pointing out that some rechargeable lithium-ion batteries can only be used with proprietary chargers. In such cases, mixing those batteries with generic chargers could result in overheating. It is always best to purchase batteries and chargers together. If chargers have to be replaced, they should only be replaced with units recommended by the battery manufacturer.
Reusable lithium-ion batteries have changed the way we live. They power nearly every portable electronic device in our homes and offices. Without them, we would have a quite different view of portability.
Thankfully, exploding batteries are rare. Despite alarming news headlines intended to sell newspapers and digital subscriptions, only about one in every 10 million lithium-ion batteries fails. That is certainly reassuring. We can use our lithium-ion batteries with confidence, knowing that there is nothing to worry about as long as we follow manufacturer instructions.