Li-Ion protection technology and possible dangers

[AW]

StrayLight,


If your P18650 did vented, it won't be working anymore. The safety mechanism would disconnect rendering the cell non-operating.

***- New Anti-expolsion Vent/PTC Module : the new module provides an added layer of protection against gas built-up in addition to the PTC thermal protection. Unlike regular vents used by most LiIon cells, these new modules will actually stop the action by separating the electrodes inside the battery when the pressure reaches a preset threshold. The vent disc will open and release the gas plus stopping the cell from further chemical reaction. Combined with the PCB electronic protection and two layers of mechanical ( thermal and pressure ) protection, these new protected cells are the first with these added safey features in place.


The New Anti-explosion Vent/PTC Module

The components inside the module : button top ( left ) , PTC ( middle ), vent module ( right )

The vent module is laser welded to another component that is connected to the cathode. When gas built-up inside the cell reaches a preset value, the vent disc will separate from the cathode and open up to release the gas. When the +ve / -ve is separated, no more energy is released.

Regular vent/PTC setup - this vent will only release gas but it does nothing to stop the action by separating the +ve and -ve. The venting only stops when all the energy is released.

Additional signs of a vented cell is sticky liquid around the +ve end and corrosion ( due to acidic nature of the electrolyte, you 'll see corrosion in 24 hours ). Smell is no indication of a vented cell. All Lithium cells do smell, primaries or rechargeables, when you put them inside an enclosed environment.

 

[StrayLight]

Well, not to be argumentative, but it's the battery that generated the awful smell and the cloudy vapor inside the CL1H. There was neither odor nor vapor when using my two p18650s in this same light for the previous 2+ months. Something has changed, and there is no evidence of of burned, singed, smoked, or melted parts in the CL1H. As I noted before, after disassembling the light and allowing it and the batt to sit for a day the smell had gone away completely. I put the same batt back in the light, turned it on for 10 sec and the battery smells terrible again. Something isn't right... if not venting, what then?

 

[Bullzeyebill]

Well, not to be argumentative, but it's the battery that generated the awful smell and the cloudy vapor inside the CL1H. There was neither odor nor vapor when using my two p18650s in this same light for the previous 2+ months. Something has changed, and there is no evidence of of burned, singed, smoked, or melted parts in the CL1H. As I noted before, after disassembling the light and allowing it and the batt to sit for a day the smell had gone away completely. I put the same batt back in the light, turned it on for 10 sec and the battery smells terrible again. Something isn't right... if not venting, what then?

Why are you playing with this 18650 if you think that it vented. Put it away, never to be used.

Bill

 

[StrayLight]

I'm not "playing" with it. You asked several specific questions regarding the event and AW said it didn't actually vent. Well, something did happen, and in the absence of any real direction or help, I tried to figure out what's going on by very briefly testing the batt twice since the event.

 

[hank]

Belated answer to #30, 32, 33, in case anyone missed this:

>I guess this is slightly OT, but why don't li-ion cells have raised "button-tops"?
>>I know what's up with that? It's so annoying trying to find something to raise the height to make contact.

NewBie covered it in #3 above.

See his entire discussion; look for the info that includes this bit:

"There is also what is known as a bare cell, which has no positive button on the end.
These are highly dangerous without more complex external electronics and temperature monitoring devices.
These are not supposed to be sold to consumers, without additional protection devices/circuits added,
and are designed for use in battery packs."

No button on the positive end --> dangerous.

---> You can't make it safe by adding a button, magnet, or bump. It's still dangerous.

 

[soffiler]

Why are you playing with this 18650 if you think that it vented. Put it away, never to be used.

Bill

Sounds exactly like the advice I already gave. If there's ANY question, take it out of service.

 

[LumenHound]

StrayLight: Has AW asked you to return the cell to him for examination?

 

[hank]

Please don't just throw it in your trash stream.
Most places that sell batteries now also collect batteries for recycling.
If nobody around you does this, and AW doesn't want it back, this will help
-- found at http://data.energizer.com/Static.aspx?Name=BatteryDisp

Call 1-800-8BATTERY or visit www.rbrc.org for help disposing safely of all these:
>> Nickel Cadmium (NiCD)
>> Nickel Metal Hydride (NiMH)
>> Lithium Ion (Li-ion)
>> Small Sealed Lead (Pb)

If you live in the United States or Canada, search by zip/postal code here:
http://www.rbrc.org/call2recycle/dropoff/index.php

You don't want the stuff ending up leaching into groundwater.

 

[LumenHound]

I'm not "playing" with it. You asked several specific questions regarding the event and AW said it didn't actually vent.

This is interesting. Has AW contacted you back with a solution?

 

[LuxLuthor]

All of us would HIGHLY recommend that you get at least a cheap DMM....which are at Sears, Radio Shack, hardware stores, online. The voltage of the cells would tell a lot of useful information. We always want to help figure out what happened to a cell whenever possible, since so many of us use them.

FYI, if there is some other electrical short a smell could come from that. Any of the regulation circuits, switch, or other components can be the source of a smell....and which would repeat if turned on again.

If you can do a bit more troubleshooting to narrow it down, that would be helpful and appreciated by most of us. I don't think anyone can yet assume it is the battery, but we do want to help you and find out what happened. Thanks for posting what you have so far. :thumbsup:

 

[soffiler]

... FYI, if there is some other electrical short a smell could come from that. Any of the regulation circuits, switch, or other components can be the source of a smell....and which would repeat if turned on again...

How does that work? A circuit, a switch, an electronic component can generate a smell? In my experience, this can be true only very briefly as a component is failing. The smaller the component, the smaller the quantity of smoke and the smaller the smell. And in this case, the light does not continue to work. The smell is generally acrid and smoky, not a chemical solvent type smell.

 

[cy]

apologies for taking so long to respond... ice storm tulsa. power still out, no web access.

good to see this thread still alive

very limited web access...

 

[StrayLight]

Please reread my previous posts... it's most definitely the battery generating the strong odor.

As to throwing it in the trash, it's a figure of speech. Batteries are one of many items I routinely recycle.

I'll look into getting a multi-meter and taking measurements, but not until after New Year's. There are too many other things going on this holiday season.

AW has contacted me with an offer to replace the battery, but did not make any suggestions regarding the faulty one.

 

[LuxLuthor]

How does that work? A circuit, a switch, an electronic component can generate a smell? In my experience, this can be true only very briefly as a component is failing. The smaller the component, the smaller the quantity of smoke and the smaller the smell. And in this case, the light does not continue to work. The smell is generally acrid and smoky, not a chemical solvent type smell.

I did not rule out the battery as the source of the smell, just that we don't have enough information to assume it yet. Your idea on an electrical component failing after a brief reaction assumes a total immediate failure.

I have had failure of a capacitor that took quite a time to develop, and also a FM battery holder that partially grounded and shorted cells slowly. Both had noticeable smells. It was not the cells at fault in that last case....and it is also possible that your light has a partial short or slowly deteriorating component.

Best to suspect everything until you are certain.

 

[soffiler]

I did not rule out the battery as the source of the smell, just that we don't have enough information to assume it yet....
Best to suspect everything until you are certain.

We can agree to disagree then. In this case, it's not best to suspect everything, it's best to TAKE THE AW CELL OUT OF SERVICE. Just my opinion. Eventually, it'll become clear if it's actually something else that is creating the problem.

 

[soapy]

I've been looking into getting some stuff made up. I've been having serious difficulty getting even a response out of anyone in the UK, and I eventually got this email today from a real expert on batteries.

Sorry but we are unable to help in the fact that it is against EU regulations to manipulate /alter or in any way change the electrical properties of rechargeable lithium cells . The reason is that they are subject to explosion and fire if shorted or connected incorrectly , also the gasses given off are poisonous and produce oxygen when burning so you have a problem dousing the fire .
We do not know how the model plane flyers get away with what they do to the lithium cells they buy but we are thinking that they buy abroad where regulations are more relaxed .
My product liability also excludes rechargeable lithium batteries . Sorry again we are unable to help .

Now what can I say, but "That sucks!"

No wonder the EU has no hi tech manufacturing base!

 

[hank]

> from a real expert on batteries

Hmmm. I wonder what the liability insurance people say.

> produce oxygen when burning so you have a problem dousing the fire

That's news to me, I think.

Are you getting things made for resale or only personal use?

 

[StrayLight]

Okay, resurrecting this thread and the "incident" with my AW p18650:

The p18650 currently measures 4.11 volts, and I have not done anything with it since the event in question. This reading is nearly identical to the other p18650 I have (the good one), hot off the charger. If memory serves, the bad p18650 was fully charged when I placed it in the CL1H and it "vented". Or not, depending on who you ask.

AW has asked that I ship the bad one back to him for examination. Anything else you lot would like me to test before I send it?

 

[DM51]

AW has asked that I ship the bad one back to him for examination. Anything else you lot would like me to test before I send it?

Intriguing situation. If this cell is reading a voltage at all, and you say it is reading 4.11V, then it has not vented.

However, it is behaving differently to the other AW 18650, in that it is giving off an (as yet undefined) smell.

You say the light is working normally with the other (non-smelling) cell. So it is probably not the light generating the smell.

The fact that these 2 cells are behaving differently is enough for me. One of them is abnormal in some way, and it seems fairly clear which one it is. You should be careful with this cell, to preserve it in its current condition (and you in yours too).

AW has asked you to ship it back to him. Please do exactly that. Please do not use it again, or do anything else at all to it. He will want to take it apart and determine what (if anything) is wrong with it. It will be useful research for him, from which everyone may eventually benefit.

 

[dbare]

Newbie question

This may be a stupid question but in wading through the Forum I can't find the answer.

I have an AA light that operates on a range of 1 to 4.7v. It also has a regulated circuit for constant brightness. When using a protected 14500 cell the light operates perfectly until, without warning, flickers and shuts down. At that point the battery shows zero volts but charges normally then operates the light normally.

My question: Is this the normal function of the 14500 battery protection circuit? If not must I continually check the voltage and recharge before it reaches 2.7v or some other arbitrary number.

Also, I have a couple of 18650 lights (Zebralight SC60w & EagleTac D25LC2) that I have yet to run down completely. Perhaps they have built in shut down circuits at low voltage?? Will they shut down the same way as the AA light ?

Thanks for any help