18650 gas release valve?

[Hummina Shadeeba]

These cells all have a valve of some sort to release gasses it seems. This is just in extreme events of high temp right and gasses aren't released otherwise?

https://batterybro.com/blogs/18650-wholesale-battery-reviews/18306003-battery-safety-101-anatomy-ptc-vs-pcb-vs-cid

 

[Syonyk]

Correct. If your cell is having a terrible day (probably deep into thermal runaway and converting it's electrolyte into a nasty, flammable mix of gasses), these will allow it to vent pressure and not explode like a pipe bomb.

If this is happening, you're still having a very bad day.