When do batteries vent?

[UncleChuck]

Sounds like a simple question, but let me explain. Some mechs that vent through a hole in the switch portion wont work when the switch is locked. This is because the air path goes out between the locking ring and the button itself. This would make the mech perfectly safe while being used, but if it's locked and stored in a pocket, it would turn into a pipe bomb basically.

So when specifically do batteries vent? I've blown up a few batteries in my day (figuring out how to recharge Njoy Kings) and they always would get very hot, then begin outgassing. Is it possible for a battery, that isn't hot, and doesn't have any current being pulled from it to vent? Some sort of delayed reaction?

I've just become paranoid about this lately, since having a 100% airtight metal tube with potentially great pressure buildup inside scares me. I generally will take several puffs, lock the switch, and place the device on a table between uses. Any possibility of it randomly venting while just sitting on the table? Obviously if something inside the mech gets wonky it could short out the battery and cause venting, but in general is it possible for batteries to vent a period of time AFTER use, or is it pretty much accepted that venting is only caused by thermal runaway, and thermal runaway can only happen under high current load, so a battery sitting there doing nothing should never vent, correct?

 

[minimalsaint]

Not necessarily. Batteries are strange little creatures and thermal runaway can happen at any rate. What mod is it that only vents while unlocked? I have personally never seen one.

 

[Richard75]

Not necessarily. Batteries are strange little creatures and thermal runaway can happen at any rate. What mod is it that only vents while unlocked? I have personally never seen one.

Same here... my Galileo vents through the button, but the locking ring has no effect on it.

Thermal runaway is kinda like a nuclear bomb. Something causes a sudden rise in temperature, which creates a chain reaction. What that something is is variable, be it external temperature or physical abuse or a hard short. I doubt physical abuse alone would cause this, but it would make it more likely, same with external temperature (unless you're planning to vape in the oven, under the "cleaning" option?) For our general purposes, I think it's safe to assume that a battery will only melt down while the circuit is complete (ie, not standing).

Batteries can be unpredictable, but this is one thing where as long as you're careful, and know what you're doing, the chances of something going wrong are very slim. A large portion of battery failures I would attribute to user error, and even if it's caused by cheap batteries, it's still kind of user error, because batteries are one thing you shouldn't pinch pennies with, especially with vaping.

If it makes you feel any better, I own a Cronus that has no vent holes... some venting through the switch, but not much. I just make sure I use IMR batteries with it, and I don't worry at all.

 

[UncleChuck]

Not necessarily. Batteries are strange little creatures and thermal runaway can happen at any rate. What mod is it that only vents while unlocked? I have personally never seen one.

The EHPro Caravela clone doesn't vent when the switch is locked. Actually it doesn't vent at ALL in stock configuration, since they don't notch the bottom section that presses against the battery. It was easy enough to put a notch in there with a file, and now I can blow air through the tube and out the vent hole, but with the switch locked down it seals the hole.

Really the only way to fix this on this specific mod is to drill a hole somewhere in the button, or to just drill a secondary vent hole somewhere else on the tube. I'll probably drill a hole through the center of the button eventually, but if batteries are "inert" just sitting in a tube I wouldn't bother. Plus I'll have to find a drill bit small enough to drill through the center of the negative battery post's threaded section, while still leaving enough material to keep enough strength there.

I could have sworn I've heard of this issue somewhere before (locked button blocking flow) but I can't think of any other mods with such a problem off the top of my head. I want to say it was one of the segelies but I'm not sure.

 

[Rickajho]

I'm not sure which mod you are referring to so it's hard to say what's going on there. Even batteries like eGo's which look like they are too well sealed up have caps on the bottom that are supposed to release in case of a venting accident. They all vent somewhere (or are supposed to) but unless you are asking about a specific PV it's hard to say much else.

NJoy Kings have very small capacity batteries. Overcharging them with anything but a 150 mA charger will likely make them go boom. They are not designed for user recharging so if you don't know what you are doing with LiOn technology don't mess with them.

I'm not aware of a LiOn battery having potential to explode when no current is applied except under two circumstances: If the battery is being shorted. Or possibly if the battery has been abused by charging at too high a current level, resulting in damage/degradation to the anode.