Why do IMR's vent while ICR's go BANG?

Hi people, I was wondering why it is that IMR’s vent fairly uneventfully(just spurt some liquids and gas) but ICR’s tend to have very, very different outcomes and explode quite violently?

The only difference is that an IMR uses Manganese instead of an ICR’s Cobalt, so why the major difference during thermal runaway, making the IMR’s a lot safer in this dangerous sitiuation? You don’t want any battery going into thermal runaway, but I would much, much rather an IMR vent on me than an ICR.

EDIT: Forgot to add, so much so I will only buy IMR batteries.

I haven’t seen many accounts of cells exploding or venting on BLF, maybe that’s common in the vaping industry.
Could you provide some links on these accounts?


There is no such thing as a safer battery failure. All batteries vent. When batteries are sealed with no venting ability (a sign of poor quality) then you will get the perceived "explosion" because of pressure build up. Nevertheless, it is the last thing one should want to happen or believe is ok as the gases and/or acids are poisonous.

Unless a battery is of the "**Fire" brand then proper care and correct usage makes any kind of venting a rarity.

True IMR batteries have a higher ignition temperature than ICR batteries. This seems to provide a bit more margin for abuse before things go really critical.

The difference has to do with the strength of the metal-oxygen bond. The cobalt-oxygen bond is weaker than the manganese-oxygen bond. So oxygen is liberated at a lower temperature from cobalt oxide than manganese oxide. When this oxygen is released, it is able to support the combustion of the electrolyte, causing the battery to vent with flame. In simpler terms, ICR is more likely to vent with flames than IMR because cobalt oxide is a stronger oxidizing agent than manganese oxide.

Thanks for you answer. Simple enough for me to understand, and why I generally go for IMR or similar chemistry :).

Heres just a battery in thermal runaway as an experiment https://www.youtube.com/watch?v=ZTzEHsJVZhA .EDIT: It goes bang around 3mins 28 seconds.

It’s a rare occurence, definitely more in the vaping community because of the stress the batteries go through (Un needed stress may I add, they now make regulated mods which are a lot safer and use PWM to get between 5-50 watts, but the new MOD’s have all sorts of inbuilt protection and do not strain the batteries as much as a mechanical mod, which is basically creating a short to make a coil heat up. It gets dangerous with people building as low as 0.09 Ohms expecting bigger clouds on mechanical mods, and making a dead short and thermal runaway. With the regulated mods super low builds are no longer needed, safer, higher resistance builds can be made to get the same watts as a low build in an older, mechanical mod. Some ‘old school’ people prefer mechanical mods, but I don’t. I don’t want to have to build a new coil when I want less or more vapour, I want to be able to press a button to adjust it. 20AMP capable Batteries are still the minimum recommended for regulated MODS though).

I don’t know if its happened in the torch community, but you would know about it. ICR make a big explosion while IMR batteries are fairly mild, spurting some liquid and gas with no explosion.

This test is genuine? Anyone done something like this before?

Placing the battery into a large glass baking pan while preforming a 1 hour dead short test, not the best idea. Even if they have tried it before and even if panasonic says it can take a dead short without “rapidly disassembling”.

I agree. Doing that is very dangerous, don’t try it even if they say their batteries could handle it.

Halo, it could be true, but I doubt it as this is 5 second bursts not an hour, as some vapers use older, mechanical mods, which are actually modified torches. They have no safety protection in place, and if you want more/less watts, you have to build a new coil to the right resistance.

Some of the more insane vapers use Mech mods at 0.09 Ohms (a dead short basically) as they are into something called ‘cloud chasing’ which is getting the biggest cloud possible.

Me, I only stick to regulated mods with safe gaurds in place, they cost a lot more, but I can vary the wattage from 5 to 50 (30 in my old device) at the press of a button, and can still ‘cloud chase’ by using high watts,but on a 1.6 Ohm coil vs a dead short coil, and as it is PWM it generally pulls only about 4 amps from the battery, I think the max on mine is 6 Amps for the 30 watter, about 9 for the 50, although it is still recommended to use a battery capable of 20amp constant discharge.

Please, don’t anyone try this to verify it. I don’t think they really dead shorted a battery for an hour with no damage at all. Seconds, maybe, but not an hour.

Hmm I wonder why vapers don’t use dedicated power supplies instead of abusing cells.

A half-decent ATX PSU can supply 20-40A on the 3.3V, 5V, or 12V rails. Is portability that important for vapers?

Very nice video. I think that battery brand manufacturers like panasonic(samsung,sony,LG and others) must have safe unprotected 1850 cells because they go into all sort of electronic equipment. They have QC and probably build safety mechanisms in cell that we can not see.

Unprotected brand 18650 cells even without pcb are safer than we actually think...

Ultra XXX fire brands from other side does not care about QC, they fill their cells with sand or dirt so explosion or some other crazy situation like flame or explosion is almost certain after some light abuse, charger fail, shorting etc...

But we need to be cautious anyway.

Portability I would say is the main reason. Some vapers have devices at home that can be plugged in, but the portability is the main thing. Also, as long as they use a regulated, not unregulated mechanical mod, they are not actually stressing the battery up to and past its limits.

It’s just a few old school heads and new kids who really abuse them in mechanical Mods. But in a regulated using PWM, its doing it quite safely, probably pulling about 4 amps.(9 on the 50 watter).

My batteries are Hybrids.
They go Snap, Crackle & Pop. :bigsmile:

PWM only regulates the AVERAGE current to the coil. The individual PWM pulses are the FULL current you would get if you just hooked the cell directly up to the coil. That can be really bad news… the cells are probably not designed for those peak current pulses. In that case, PWM is only giving the impression of being safe when it is actually about as dangerous as directly hooking the cell to the coil.

Nothing wrong with ICR cells… IF TREATED PROPERLY.

Think about it this way, if you’ve ever used a laptop, you’ve used ICR cells. Most of my unprotected 18650’s come form HP and Sony laptop batteries. No problems here.

I never go above the rated 20 Amps on my batteries, rarely above 6, so keep well within the range even though its PWM( I said I used PWM as thats what I choose over constant DC-dc mode). It also contains transformers to up the voltage and such from less power, kind of like a step down transformer in reverse.