Is there any sign before a battery explode?

[louis2008]

I have heard about battery in smartphones exploded, but I did not study the details.
Now, I am going to replace my battery, but since the model is a bit old, there is no way to replace it with the original battery, so chances are I am probably getting a generic battery or even a counterfeit one from a shop that fixes smartphone,

Is there any sign before a battery explode, or could it happen without any sign? Then it would be so dangerous!

 

[nickdalzell]

Swelling is the most common one. It's also called a 'spicy pillow' since sometimes the back pops off to reveal a pillow-style puffy battery.

Otherwise it can get very, VERY hot. Suddenly. It's called thermal runaway and can result in either the pillow or an actual spewing of contents or even fire. Usually results from a shorted cell that causes a cascade failure on any Lithium battery.

 

[ocnbrze]

^^^^^^this^^^^^^^

 

[louis2008]

Swelling is the most common one. It's also called a 'spicy pillow' since sometimes the back pops off to reveal a pillow-style puffy battery.

View attachment 167105

Otherwise it can get very, VERY hot. Suddenly. It's called thermal runaway and can result in either the pillow or an actual spewing of contents or even fire. Usually results from a shorted cell that causes a cascade failure on any Lithium battery.

Hi, in other words, is it just quite unlikely that even a cheap counterfeit battery will just explode without all these signs?

 

[Hadron]

Unlikely. The first sign will probably be either the screen or the back of the phone popping out (depending on the design of the phone). But if you see any sign of bulging do not charge it.

I mean, it's not physically impossible for a battery to be so bad that it fails suddenly. But you want to use a repairer you have at least some confidence in, and it's hardly in their interests to fit batteries that might explode because that's likely to come back to them. Manufacturers usually claim (correctly or otherwise) that fires are caused by people using poor quality third-party chargers rather than replacement batteries (mainly because most reported cases don't involve replacement batteries but the battery the manufacturer installed!).

 

[nickdalzell]

'counterfeit' batteries have become far less common since batteries are now sealed. Back in the removable battery days, tons of third-party batteries, including dodgy ones, existed. Often it bit those who kept their devices long-term, and the OEM supply had long since run out.

That said, it won't be sudden most of the time. Leaving your phone on charge long-term can cause it, and it shows itself today by being so slightly bulged that you wouldn't notice it until your phone becomes a sort of fidget spinner because it's no longer level on the table. However, the Note 7 was a thing. Those phones, sealed batteries and all, were instantly cremating themselves despite two recalls later. Enough that Samsung issued a software update first to limit charge to 65%, then later to disable the ability to charge, essentially killing the model that way.

The only time a Li-Ion battery does instant fire is when they have a dead short inside them. You'll be aware when the phone gets so suddenly hot that it's burning you somehow. Li-ion fires/shorts are not as common as they used to be, but occasionally happen, much to the dismay of a certain few Tesla owners.