"Bad", "Pipe bomb", "Boom", etc... What can I really expect?

So I was sharing some battery safety tips with my gf yesterday and she asked me what she could expect if something went catastrophically wrong and a battery went into thermal runaway. The answer is that I don't really know, and in thinking about it it made me realize that I have plenty of questions myself.

My understanding is that a battery starts having issues because of heat, correct?

Heat can be brought on by drawing too much energy too quickly, or from a short. What else can cause heat build up in a battery?

When the battery has become unstable from heat, the pressure causes the battery to vent at the positive contact. If that happens, what do you do then? Call the bomb squad? But really, after it vents is it still dangerous, and if so, for how long? What about ppe and clean up?

I often see things that are too vague to be of any real use. For example, Zamplebox has some fantastic safety articles that I trust. Only thing that I don't like is that instead of saying what can happen at too low a build they simply say "Boom". I guess they can't know for certain what WILL happen, but I'd like to know what MIGHT happen.

Thermal runaway is an abnormal condition. Venting is a designed safety feature. Do batteries typically go straight into TR, or do they vent first?

About different battery sizes... Is a 2x700 battery more dangerous than an 18650 because it's physically larger? Is a high drain battery more or less dangerous than a high capacity/low cdr battery? I guess that would involve the chemical makeup of the battery?

I believe I have enough understanding to keep myself safe under the conditions that I put my batteries under. I understand what to do, and what not to do. I mostly understand why. I don't have a firm grasp on what to do if a problem occurs, and that doesn't sit well with me. I kind of wish that I could push a battery to failure so that I could get an understanding of what happens. I've watched YouTube videos, but they don't tell me much beyond what a TR explosion looks like. Not discounting their value, of course, because I kind of had this vision of a higher energy explosion like a grenade or stick of dynamite.

I'm in the process of switching over entirely to Sony VTC5A's. I have a few straggling HG2's, a couple of VTC6's and the odd 25R, 30Q and Hohm Tech battery that I throw in regulated mods. Mechs all get 5A's or 5 leg ijoy 20700's. Soon I'll be switching the big batteries to Sanyo ncr20700a's, but that's because of performance, not safety. My 26650 batteries are Hohm Tech and serve me well enough in regulated mods. I don't have any 26650 mechs, but even if I did, I'm not aware of a better cell than the HT Hohm Grown.

I will have a need for 18350's soon enough. Anyone have a recommendation for these? What about 18500's? If I need those it'll probably be down the road a ways but who knows. I may stumble upon a deal on a mech that uses 18500's that I can't pass up. I'll go over what Mooch recommends (as always), but if you have something that has worked well (or hasn't) I'm listening.

I know there are a lot of questions in this thread. I appreciate any answers or thoughts. I'm not sure anyone here has experience with TR or any other abnormal battery conditions, but I don't know of a better place to ask.

Thanks for any contribution guys! Feel free to add questions too.

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if it goes into thermal runaway then a bunch of gases leak out and you're OK.
But they can explode if you have a dead short.

They won't go up as bad as a pipe bomb . . . it's more like a Roman Candle.

I had first-hand experience with wiring going awry in Ego clone and causing a short.

Just buy the highest CDR batts you can from reputable vendors and brands..... as long as you don't pull more amps than ratings. . It shouldn't go critical.... IN THE MOD. unless it's during recharge....

Fact Is most batteries go critical when charging. So only charge in mod when you have no other options.

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They can do This: (skip to 1:40 to not waste time)

I'm sure most of you have heard this all before, but better to be bored by repetition than go through the excitement of having to file an insurance claim.

A) Keep an eye on your wraps, especially if your vape uses the all-metal battery clips (which can short from the case to the positive terminal), or if the batteries touch (can short one of the batteries by touching cases). Wraps are really cheap and if needed get a hairdryer from a thrift store to apply them.

Personally I prefer heavier PVC shrink wrap (3/4" for 18650) to the flimsy stuff some places sell as "wrap" that's no better than the original wrap, but it may make the battery too tight in some mods.

B) Charge externally -- mods' battery balancing and ventilation are "iffy." To be extra save, put your charger on a fireproof surface. I like clay floor tiles from "home improvement store." Or scour the aforementioned thrift store for cheap glass/ceramic baking ware.

C) Buy quality batteries (besides being rated for the amperage, more likely to just vent than make fireworks)

I'm talking about this style of terminal:


Hole in the wrap: path of current if battery cases short in bad ascii form (paintshop would be worse)
"." is the insulator
"x" is the short-circuit current flow
"=" is the connecting plate
Hopefully shows why mod protection can't help with this kind of short.

A better quality battery *should* do this instead of causing fire, but batteries can be unpredictable.
Cut to 4:35 to get to the action.


Ebay battery:

Had one go on me in my SMPL mod a while back,it was my fault, changed batts in the dark and grabbed one that had a nick in the wrap by mistake.

I put the batt in the tube, screwed the switch in, went to test fire before taking a puff, and as soon as I touched the switch, it flew out of my hand like a bottle rocket, hit the ceiling and made it about four feet from where I was, the tube was so hot it melted a hole in my carpet where it landed.

Picked it up with tongs, threw it outside in the snow, where it sizzled for a good long while.

It fused the switch in the tube and melted my freak show I had on it. Left six little holes in my index finger from the jet blast. Even left some jet burns on my couch.

No explosion, and no real harm done other than to the mod and carpet. Scared my wife half to death. It was a 25R battery in it FYI.

That sort of goes against everything I'm searching for. I already have the batteries tha

HondaDavidson said:

Just buy the highest CDR batts you can from reputable vendors and brands..... as long as you don't pull more amps than ratings. . It shouldn't go critical.... IN THE MOD. unless it's during recharge....

Fact Is most batteries go critical when charging. So only charge in mod when you have no other options.

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That sort of goes against everything I'm searching for. I already have the batteries that my builds require. Nah, I'm in search of information to fill out the blank spots in the old knowledge bank.

I don't charge in mod because out of a whole lot of mods I have exactly one mod (Therion-75c bf) that features a USB port with charging. The single 18650 I'm comfortable would charge fine in, but my regular charger is 3a, so 3-6 times faster than the mod. Yes, I know 3a isn't ideal for the batteries but many are rated near (or at) 3a for fast charging. The fact that I can only expect a year from them is a non-issue since there are likely to be batteries that I'd rather have anyway before then. $6 per battery/per year is peanuts for the convenience. Oh snap. I think the Hohm Wrecker G2 might also charge via USB? Can't remember, but she's retired.

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5150sick said:

if it goes into thermal runaway then a bunch of gases leak out and you're OK.
But they can explode if you have a dead short.

Click to expand...

You got it a little mixed up. Venting is when gases leak out. The cells are designed to do this if they get too hot, so that they don't explode.

Thermal runaway is when the battery gets so hot, so quickly, that it can't vent in time to release the gases, causing the battery to blow up. The reason a hard short can cause thermal runaway is because the batteries will give whatever they have. When you hard short a cell, it tries to give everything it's got because there is no to little resistance to impede the flow of electricity. The cell discharges so quickly that it can heat to thermal runaway temps in an instant.

One reason to buy quality batteries is that they are more likely to vent rather than go into thermal runaway in the event of a short. This isn't a guarantee though. Even vtc5a's can go into TR.

OP, if you have a venting battery just get it away from you asap. Try to throw it outside or onto a non flammable surface. Let it rest for at least an hour, then you can grab it. The chemicals inside the battery are toxic so try not to get any on yourself.

One more thing that might help you understand this stuff a little more. Tube mods have been known to explode and are sometimes compared to pipe bombs. This is because if they don't have proper vent holes in the mod, a venting cell can make the tube blow up. If your mod has vent holes on top, but you put the cell positive down, then in the case of a venting battery the cell can swell and block off the patch that the gas would use to escape. What results is pressure building in the tube and then the tube will blow up like a pipe bomb.

I hope that helped clear some of that up for you.

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ALL vapers with mods that have removable batteries should watch Mooch's vids.
It is THE best source of battery safety and knowledge to be the most out of your vape.

https://www.youtube.com/channel/UCePHh3NMvu3rW2LFJeOWo-Q

Good stuff folks. I especially like the story about the SMPL.

Btw, I was one of the first subs on Mooch's YouTube channel. I believe I posted here that he'd finally put it up a couple of hours after he did. Definitely a good thing for all of us to view, be it first understanding, or brush up. He's easy to watch and is a great teacher.

Thanks to everyone who has added something so far! Still have those questions about battery capacity, and the new large form factor cells.

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it took about 7 seconds to melt the wrap on my battery when i put it in my SMPL mod backwards by accident (wrap already had a tear... ). I felt it getting hot so i popped the batt out, but it died soon after (that drastically shortened its life span).

if a battery gets hot enough to melt the wrap recycle it.
It is seriously damaged and could vent under normal use or anything.
Not worth the risk.
Watch the Mooch vids and learn.
or not, it is your face and life.

tossed that one long ago!

If a person is here on this forum they have most likely heard of Mooch. There's nothing wrong with suggesting someone take a look at what he has to say, however, I caution against assuming someone's level of knowledge or willingness to learn.

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Fudgey Finger said:

You got it a little mixed up. Venting is when gases leak out. The cells are designed to do this if they get too hot, so that they don't explode.

Thermal runaway is when the battery gets so hot, so quickly, that it can't vent in time to release the gases, causing the battery to blow up. The reason a hard short can cause thermal runaway is because the batteries will give whatever they have. When you hard short a cell, it tries to give everything it's got because there is no to little resistance to impede the flow of electricity. The cell discharges so quickly that it can heat to thermal runaway temps in an instant.

One reason to buy quality batteries is that they are more likely to vent rather than go into thermal runaway in the event of a short. This isn't a guarantee though. Even vtc5a's can go into TR.

OP, if you have a venting battery just get it away from you asap. Try to throw it outside or onto a non flammable surface. Let it rest for at least an hour, then you can grab it. The chemicals inside the battery are toxic so try not to get any on yourself.

One more thing that might help you understand this stuff a little more. Tube mods have been known to explode and are sometimes compared to pipe bombs. This is because if they don't have proper vent holes in the mod, a venting cell can make the tube blow up. If your mod has vent holes on top, but you put the cell positive down, then in the case of a venting battery the cell can swell and block off the patch that the gas would use to escape. What results is pressure building in the tube and then the tube will blow up like a pipe bomb.

I hope that helped clear some of that up for you.

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Click to expand...

Thermal runaway is not necessarily always an explosion. In a lot of cases the battery becomes a rocket engine that, if it isn't held by anything, can literally lift itself up in the air and bounce off of the walls and ceiling multiple times before it lands back on the floor. It can happen in two stages so it can still cause an explosion seconds after turning into a rocket engine. There can also be venting before going into thermal runaway. Worst case scenario it explodes immediately without warning and causes the metal that the mod is made of to be ripped to pieces resulting in shrapnel flying around in a radius of like 10 ft. or even farther. But in order for thermal runaway to happen, you'd have to stress the battery really, REALLY hard. The risk of it still happening without stressing the battery hard is so low that it is completely negligible, albeit now we are talking about undamaged batteries so... if the battery is dented, then that might cause an internal short inside the battery resulting in a very high risk of going into thermal runaway.

If you happen to be standing in front of a sink full of water, then dropping the mod in that would be the safest, single most effective way to prevent thermal runaway and to stop thermal runaway once it occurs. If having to decide between 1/ putting the mod down on a non flammable surface and 2/ throwing the mod as far away from oneself as possible, then keep in mind that there is no standard answer as for what's best because 1/ there might not be sufficient time to still be able to flee away from hazard, and 2/ the batteries might explode on impact wherever the mod lands.

A fully charged battery is more dangerous than a depleted battery since it is storing more energy at the time of failure, correct? Does that mean, then, that an "energy" battery is more dangerous (in tr) than a "power" battery?

I think I need to get a better understanding of how energy is actually, chemically, stored, and how it is delivered before I can fully understand mode of failure.

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strigamort said:

A fully charged battery is more dangerous than a depleted battery since it is storing more energy at the time of failure, correct?

Click to expand...

Not necessarily. Over-depleted LiPo's are potentially dangerous. They can internally short themselves because metal crystals start forming.

From http://www.mpoweruk.com/lithium_failures.htm

Under-voltage / Over-discharge

Rechargeable Lithium cells suffer from under-voltage as well as over-voltage. Allowing the cell voltage to fall below about 2 Volts by over-discharging or storage for extended periods results in progressive breakdown of the electrode materials.

• Anodes
  First the anode copper current collector is dissolved into the electrolyte. This increases the self discharge rate of the cell however, as the voltage is increased again above 2 volts, the copper ions which are dispersed throughout the electrolyte are precipitated as metallic copper wherever they happen to be, not necessarily back on the current collector foil. This is a dangerous situation which can ultimately cause a short circuit between the electrodes.
  
• Cathodes
  Keeping the cells for prolonged periods at voltages below 2 Volts results in the gradual breakdown of the cathode over many cycles with the release of Oxygen by the Lithium Cobalt Oxide and Lithium Manganese Oxide cathodes and a consequent permanent capacity loss. With Lithium Iron Phosphate cells this can happen over a few cycles

Click to expand...

I suggest reading more of that site if you you're interested.

strigamort said:

A fully charged battery is more dangerous than a depleted battery since it is storing more energy at the time of failure, correct? Does that mean, then, that an "energy" battery is more dangerous (in tr) than a "power" battery?

Click to expand...

Yes if we can assume that the battery doesn't get over-discharged, and yes if we can assume that the "energy" battery uses the same chemistry as the "power" battery (which isn't necessarily always the case). Mooch did an episode explaining a little bit about different battery chemistries on his personal YouTube channel not too long ago.

I think I need to get a better understanding of how energy is actually, chemically, stored, and how it is delivered before I can fully understand mode of failure.

Click to expand...

Mooch also briefly explained that without becoming too technical.

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One line summary: Batteries are chock full of chemical energy (possibly even when "drained"), but you only want the chemicals to react in a certain way to get electricity and not excitement.

Blargh23 said:

One line summary: Batteries are chock full of chemical energy (possibly even when "drained"), but you only want the chemicals to react in a certain way to get electricity and not excitement.

Click to expand...

Without all the excitement that vaping has to offer as a hobby I'd probably still be smoking cigarettes.

Use your adult brain,
You should be fine.
Maybe.

randallpiz said:

Use your adult brain,
You should be fine.
Maybe.

Click to expand...

I've learned over the years that my adult brain is not to be trusted.

Blargh23 said:

I've learned over the years that my adult brain is not to be trusted.

Click to expand...

Whatever you do, don't let the voltage of your brain go below 2 volts, and don't let your positive ear touch your negative ear.

randallpiz said:

Use your adult brain,
You should be fine.
Maybe.

Click to expand...