Bulging Li-ion battery – is it an immediate danger? What’s the likelihood of explosion? I have a macbook battery that shows as completely dead (doesn’t hold the laptop on even for a second). It now started bulging, and in last week it inflated to about 50 % extra thickness, like this – I can see the inflated battery packs filled with gas.



How big of a danger is to keep a battery like this at home? Will the reaction stop, or will it continue and will the pressure rip through the battery packs?

If that happens, will the battery combust? Internet is full of videos of exploding batteries, but what’s the real likelihood? One in a million? Or one out of two if it swells like this?

I found an advice to keep the battery in a bucket of salty water, does that make sense (I remember that water + lithium = intensive fire)?

How are Li-ion batteries disposed of when I take them into store?

I ask here, because I couldn’t find a qualified answers on the internet, only scare articles about explosions and vague conflicting advices. Thanks!
The battery may have already ruptured due to thermal runaway, meaning that despite it being bulged, pressure from boiling electrolyte has already escaped.  In this case it is also likely that the lithium graphite electrode has already degraded through reaction with air.  If this is true, you are lucky that the previous thermal runaway did not result in a fire.

However, it is impossible to say that the the battery is completely dead without more information, information that would require making measurements that are difficult or impossible for most home chemists.  Thus there may well still be appreciable amounts of flammable electrolyte and air-reactive lithium graphite remaining in the battery. If heated or allowed to react with air, any such material could re-pressurize the system, resulting in a fire or small explosion.  In awareness of this possibility, you should still treat the battery as dangerous.