Information on RCr 123 Explosion?

[degarb]

1. Exactly how damaging could a headlamp with an exploding rcr 123a be to a user wearing a hat?

2. How likely is a protected 880 in a single cell light?

3. Why is the word "fire" used in most of the LIon names? Give me the creeps.

 

[Norm]

Re: RCr 123 Explosion

liion fire - Google Search
Check out google
Norm

 

[degarb]

Re: RCr 123 Explosion

liion fire - Google Search
Check out google
Norm

I am giving up at the 20th link and a couple variants on the search term. Do you see a link there telling you anything related to my questions? Like, in this size battery 123, how big is the explosion? Could it make it out of a plastice case of a head lamp. Would a hat protect the user?

What percentage is the risk factors and how to mitigate? etc. Yes, I know they can explode. But any heard of anyone killed by one? or loosing a hand by an exploding flashlight?

 

[SilverFox]

Re: RCr 123 Explosion

Hello Degarb,

As long as the nipple end of the battery is pointed away from my face, I wouldn't worry about using a CR123 headlamp.

As far as the size of the "rapid venting" incident goes, the ones that I have experienced will see the cell traveling 5 - 10 feet. They have enough velocity to dent drywall, but not enough to penetrate it.

Tom

 

[Black Rose]

Re: RCr 123 Explosion

As far as the size of the "rapid venting" incident goes, the ones that I have experienced will see the cell traveling 5 - 10 feet.

Call me weird, but as scary as that sounds, I'd like to see that

 

[45/70]

Re: RCr 123 Explosion

I'm going to join in here, briefly. I would like to point out that incidents involving single cell primary or Li-Ion applications are rare. I would also like to add that most lithium incidents when actually in use, involve lithium primary cells. Li-Ion cell incidents are almost always when charging the cell, not when they are in use. Note, I said almost.

Personally, I would feel safer with a Li-Ion cell strapped to my head than a primary, but again, in a single cell application, incidents are rare with either chemistry.

I'm no expert, but I pay pretty close attention to this subject, as my Li-Ion collection is starting to rival my NiMH/NiCd collection.

Dave

 

[SilverFox]

Re: RCr 123 Explosion

Hello Black Rose,

You may find this video informative...

Tom

 

[Mr Happy]

Re: RCr 123 Explosion

That was a primary lithium I think? Not that it wasn't spectacular or anything...

 

[Black Rose]

Re: RCr 123 Explosion

Wow, that sucker really went off.

What causes something like that?

 

[Mr Happy]

Re: RCr 123 Explosion

Wow, that sucker really went off.

What causes something like that?

Overheating, probably. It looks like that cell was shorted out and allowed to get too hot internally until it failed. The better brands of lithium cell contain a PTC (positive thermal coefficient) device to limit the current in the event of a short and reduce the risk of that happening.

A lithium cell like a CR123A contains a highly combustible substance (metallic lithium), and powerful oxidizing agents (such as manganese dioxide and lithium perchlorate). Another common device -- the firework -- also contains highly combustible substances and powerful oxidizing agents.

I think you can see where this is going...

Under normal conditions the contents of a lithium cell are kept under control and nothing bad happens. However, under abnormal conditions such as an excess rise in internal temperature, the ingredients can cross the stable threshold and start a runaway reaction. If this ever happens, the lithium cell becomes a roman candle as shown in the video.

(Note: Overheating is not the only way to explode a lithium cell. Reverse charging is another way. Reverse charging can remove lithium from the cathode and electroplate it on the anode where it is in finely divided and intimate contact with the powerful oxidizing agent. This is very unstable and also likely to turn into a roman candle.)

 

[SilverFox]

Re: RCr 123 Explosion

Hello Mr Happy,

A few clarifying points...

Those tests were done with primary cells that were purposely mismatched by around 15%. The original problem was that the cells in a flashlight rapidly vented with flame and ruined the light. After going through a few flashlights, it was discovered that you could wrap the batteries in some foil, mount them in a makeshift holder, attach a lamp and do the same tests without blowing up an actual flashlight.

Those cells have PTC devices, but they didn't seem to help.

The lamp drained the batteries in a little less than an hour, then the whole system was left connected while the stronger battery reversed charged the weaker one. The video shows the end of the test.

Some of the failures were more spectacular than others.

Attempts were made to record the cell temperatures, but once the cell vented, things moved around and we are not sure if the maximum temperatures were accurate. We did measure temperatures exceeding 700 F. Obviously the flame temperature were higher.

Tom

 

[LumenHound]

Re: RCr 123 Explosion

Why is the word "fire" used in most of the LIon names? Give me the creeps.

Not a good mental image. Bad optics for sure.

Similar to an auto tire retailer with a roadside sign stating "Big Spring Blowout Sale-Prices Slashed!!!"

 

[Mr Happy]

Re: RCr 123 Explosion

Thanks for the extra information. I didn't find the thread describing the experiment.

If it was reverse charging, then the result will be less sensitive to temperature. Once you have the finely divided lithium plated on the anode than it would not take much to initiate the runaway reaction. Once (and if) that reaction has started, then it will continue and temperature no longer has much importance to the final result. It's exactly like lighting a firework -- once it's lit, there is no stopping it.

A PTC would not protect against reverse charging since a small current for a long enough period will suffice to cause sufficient electroplating of lithium in the wrong place to produce an unstable system. A PTC is really there to protect against direct shorts which otherwise would produce large currents and excessive internal heating.

Wrapping the cells in foil would act as a thermal insulator, which would encourage the conditions for a runaway reaction to start. Chemical reaction rates are exponentially sensitive to temperature. Given the right starting conditions, even the heat of your hand or body may be enough to make the difference between venting with flame or nothing happening.

It really surprises me that lithium cells are described as safe. It's true that out of millions of cells produced very few undergo vigorous autonomous destruction, but the fact that some can be persuaded to do so under fairly predictable use cases is enough to make me nervous.

 

[Black Rose]

Re: RCr 123 Explosion

It really surprises me that lithium cells are described as safe. It's true that out of millions of cells produced very few undergo vigorous autonomous destruction, but the fact that some can be persuaded to do so under fairly predictable use cases is enough to make me nervous.

After reading what you and SilverFox wrote, I am a bit leery of putting lithium cells (AA) in an aluminum body flashlight to be kept in the car.

They (lithium) seem to be the best bet compared to alkaline or LSD NiMh for that use (operating temps, storage life), but I think I'd rather take a chance on the LSD NiMh self discharging faster than have a lithium cell take out my car.

 

[LumenHound]

Re: RCr 123 Explosion

It really surprises me that lithium cells are described as safe. It's true that out of millions of cells produced very few undergo vigorous autonomous destruction, but the fact that some can be persuaded to do so under fairly predictable use cases is enough to make me nervous.

Well, generally speaking, they are safe.
I'm curious, what is it about the description of Li-ion cells that you find lacking?
For me, I'd like to see charging warnings printed on the cell wrappers at the very least.

There are always ways to make things safer.
If we could improve safety procedures with regard to charging and discharging Li-ion cells, what else would you suggest?

 

[Illum]

Re: RCr 123 Explosion

The lamp drained the batteries in a little less than an hour, then the whole system was left connected while the stronger battery reversed charged the weaker one. The video shows the end of the test.

Some of the failures were more spectacular than others.

something else to keep in mind, there are threads in which SINGLE celled lights have vented...so obviously reverse-charging isn't the only culprit

 

[Mr Happy]

Re: RCr 123 Explosion

I'm curious, what is it about the description of Li-ion cells that you find lacking?

Well this thread actually took a slight diversion. Although the title is about Li-ion cells, the video that SilverFox linked to and my subsequent observations are about lithium primary cells like the CR123A.

I think Li-ion cells pose less of a danger to the average person since the bare cells are not mass-marketed for consumer use and are mostly designed into consumer products with appropriate safety circuits and carefully designed charging systems.

The greater danger with Li-ion cells seems to be when people like flashoholics and RC enthusiasts buy the cells as unpackaged items, and when counterfeit battery packs for phones and laptops get into the supply chain that don't meet the same standards of manufacture as the genuine OEM item. In the case of enthusiasts, buyers must be aware of the dangers and inherent risks of mistreatment and be responsible for how they charge and use the batteries. I'm actually 100% in favor of people's freedom to be responsible for their own safety, so I'm not arguing for such items to be banned or anything like that.

 

[SilverFox]

Re: RCr 123 Explosion

Hello Mr Happy,

While the reactions leading up to the rapid venting with flame incidents are different between lithium primary and Li-Ion cells, the resultant "fireworks" is quite similar.

You mentioned that with reverse charging you thought that process would be less sensitive to temperature. The actual testing did not bare that out. When the ambient temperatures were in the high 80's F, this rapid vent with flame incident was very repeatable, with some batches of cells. However, when the temperature dropped, the rapid venting with flame could no longer be produced.

I have no idea exactly what that indicates...

Getting back to Li-Ion cells...

The greatest danger occurs during charging, followed by physical damage. A headlamp powered by a Li-Ion cell should not be dangerous during use, but a multi cell Li-Ion battery pack may become dangerous during charging.

Tom

 

[Mr Happy]

Re: RCr 123 Explosion

You mentioned that with reverse charging you thought that process would be less sensitive to temperature. The actual testing did not bare that out. When the ambient temperatures were in the high 80's F, this rapid vent with flame incident was very repeatable, with some batches of cells. However, when the temperature dropped, the rapid venting with flame could no longer be produced.

That wasn't quite my intended meaning. Perhaps I can clarify.

What I was suggesting was that a vent with flame incident triggered by heat alone would require much higher temperatures than one produced by reverse charging.

An ambient temperature in the high 80's F could easily be reached on a hot summer day in a car for example, and it is to be hoped that under normal conditions the cells are stable and safe at such temperatures. The internal cell temperatures created by an unprotected short circuit would be substantially higher than this.

Reverse charging is different. Under reverse charging conditions lithium metal gets transferred to the wrong part of the cell where it forms a very unstable system. Once this has happened the cell is very sensitive to temperature and is balanced on a hair trigger. It doesn't take much of a push to set it off. I mentioned about the heat of the human body possibly being enough to make the difference and your comment about the high 80's bears this out.

I should also mention that I don't believe the cell failure would have to happen at the time of the reverse charging. It could happen later on. Once the reverse charging has put the cell into a bad state it has become unstable and would remain that way for a while. So you could do the reverse charging at low temperatures with apparently no result, then later warm up the cell after removing it from the circuit and that could be enough to set it off.

 

[SilverFox]

Re: RCr 123 Explosion

Hello Mr Happy,

I fully understand and agree...

Tom