123 cell protection anatomy revealed

[NewBie]

Warning!!!

Please do not attempt to do this, it can be very dangerous!

Some folks have argued about the existance of a PTC in 123 batteries. I'd like to assure folks that at least Duracell, Energizer, and Surefire all use PTC devices in their Primary Lithium Batteries.












I also took the PTC and measured it's resistance with temperature, and once it hit a certain temperature, it's resistance rapidly increases, to remove the load to a cell, in order to protect the user from a battery explosion.


Next, the rest of the cell:

[carrot]

So these batteries are just rolls of... electrodes? I don't quite remember chemistry class.

I'm surprised... I thought there were pixies inside.

[idleprocess]

Thanks for risking life, limb, and the wrath of product-liability attorneys everywhere to bring us this most informative photographic journey through lithium-primary cell construction!

[NewBie]

Originally Posted by carrot

So these batteries are just rolls of... electrodes? I don't quite remember chemistry class.

I'm surprised... I thought there were pixies inside.

Heheh, you also find electroyte.


Some of the atypical stuff found in a Primary Lithium:

-Carbon Black
-1,2-Dimethoxyethane
-1,3-Dioxolane
-Graphite
-Lithium or Lithium Alloy
-Lithium Perchlorate
-Lithium Trifluoromethanesulfonate
-Lithium Trifluoromethanesulfonimide
-Manganese Dioxide
-Propylene Carbonate


Thermal degradation may produce hazardous fumes
of:
-manganese and lithium,
-hydrofluoric acid
-oxides
-carbon
-sulfur
-and other toxic by-products.

Under certain misuse conditions, and also by abusively opening the battery, exposed lithium can react with water or moisture in the air causing potential thermal burns or fire.

BATTERY CAN EXPLODE OR CAUSE BURNS IF DISSASSEMBLED, RECHARGED, OR EXPOSED TO WATER, FIRE, OR HIGH TEMPERATURE.

[kubolaw]

Wow, great stuff. Thanks NewBie!

It looks like the protective element is a sandwich of two metal disks separated by the PTC material. Does that mean that if a strong axial force is applied to the cell, the disks could short and bypass the protection? Or am I not looking at the pictures properly?

[a99raptors]

Thanks and great work! What about the cheaper batteries like BatteryStation (Made in PRC) and Titanium?

[Stumpy]

Thanks for the bird's eye view it is very interesting.

[chimo]

I love posts like this. Thanks, Newbie. I hope you had your EOD suit on.

Paul

[Burnt_Retinas]

Great pics,

Now add water to the grey electrode material, some of which is attached to the insulating liner. It's got the lithium. Keep the cell wrapped when adding water will give flames as it appears to ignite the insulating liner with the heat produced.

If anyone intends to pull apart a cell, please unwrap the layers and spill some water on it whilst outdoors. This will 'fizz' off the lithium, hopefully without any major fire. Not doing so may cause a fire hazard when disposed of in the trash should any lithium come into contact with moisture (most likely).

Chris

[SilverFox]

Hello Newbie,

Excellent information, and my hat is off to you... Every time I have taken a cell apart it has caught fire.

Tom

[KevinL]

Great job on the disassembly and the photography! That has been the best 'exploded view' of the interior of a cell that I have ever seen, bar none.

Lots of stuff inside the humble little 123 cell that we all use.

[Luna]

What happens if you throw that in the toilet

[jsr]

Originally Posted by a99raptors

Thanks and great work! What about the cheaper batteries like BatteryStation (Made in PRC) and Titanium?

Titanium states they have PTC. I too would like to know if BS 123As have PTC, but thus far, no one's been able to answer that when I ask.
I know Tenergy doesn't have PTC and these are the 3 low-cost brands I'm looking to purchase from in the future (when my current stock runs out).

[BigHonu]

WOW!

Excellent job with the disassembly and photography!

[bwaites]

I'm willing to bet that BatteryStation cells have PTC. Otherwise, why would they shut down when overheated?

Bill

[a99raptors]

Saw the discharge curves over at the amondotech website regarding several 123 batteries that claim that titanium and batterystation batteries holds a greater charge for a longer time than any other batteries. I was just curious as to how true this is, considering their prices are also among the cheapest. Just wondering if they sacrifice reliability for lower prices.

http://www.amondotech.com/images/lit...mparison2A.jpg

[jayflash]

Is the lithium in a totally discharged cell reduced or combined such that it's in a stable form and won't react with water?

[Brighteyez]

You've made this posting in a rather authoritative demeanor. Do you know this for a fact, or was it just told to you (even if it was from Tenergy, as things might get lost in the translation, and I don't think the two ladies who answer the phones are real technical.)

I don't have any of their CR123 batteries, so I can't really tell for sure one way or the other either.

Originally Posted by jsr

I know Tenergy doesn't have PTC

[JimH]

Originally Posted by Luna

What happens if you throw that in the toilet

Have you seen the Movie "Lethal Weapon 2". If not, rent it. It will answer your question.

[NewBie]

I will mention there is a little trick that is common in Lithium Ion Secondary cell manufacturing, that may be used for Primaries...

What they do is they over-crimp the PTC into the cell, with extra pressure/force. This actually causes the PTC current threshold to rise a bit. I've heard that you can get an extra amp out of them this way, before they kick off. I've seen several papers that warn against doing this, for a variety of reasons.

If you look, in one of the photos, you will see an indentation on the PTC ring, from the crimp. You do not want to "overdent" the PTC, as it will defeat it's function.

The vent ring with vent liner is in the bottom of the top, then the PTC is put in, then the button top (all with necessary insulators/liners), then the whole assembly is crimped shut by the outer negative can portion.

[Ray_of_Light]

Thank you Newbie for the hard (and dangerous) work!

I want to add just some notes. The positive electrode is the grid, made of an alloy of nickel, and has that black powder distributed in the holes. The black powder is the Manganese Dioxyde mixed with graphite.

The white porous membrane acts as physical separator and ionic conductor. It is wetted with the liquid, organic electrolyte. If the membrane melts, the battery is shorted.

The grey solid film is the lithium, the negative electrode. Once the battery is cut open, the lithium will keep generating hydrogen, as result of presence of water in the air.

The 123s use a wound structure, like Ni-MH batteries, to reduce their internal resistance.
An organic electrolyte must used due to high reactivity of the lithium with any water based compound. It has a specific resistence that is much higher than comparable acqueous solvent, and a wound structure reduces the resistance - since the exposed surface increases.
Alkaline batteries and backup lithium batteries use a non-wound structure (called "bobbin" structure).
No other commercial primary cells, aside from lithiums, use the wound structure, since it is expensive to produce.

Anthony

[Kiessling]

WOW!
Thanx !! Very interesting ...
bernie

[jsr]

Originally Posted by Brighteyez

You've made this posting in a rather authoritative demeanor. Do you know this for a fact, or was it just told to you (even if it was from Tenergy, as things might get lost in the translation, and I don't think the two ladies who answer the phones are real technical.)

I don't have any of their CR123 batteries, so I can't really tell for sure one way or the other either.

I was told this by the owner of BatteryJunction who carries Tenergies when I was looking into Tenergy cells. Seeing as PTC is a good selling feature, I wouldn't see any reason for him stating the Tenergy cells lack the PTC if it wasn't true. There's no way of knowing this by my opening the cell as I don't want to take the risk of doing so. Until Newbie opened up a cell, much of the info we had was also by someone just telling you (might be someone technical, the designer, a physicist, or just someone who played a lot with it and broke it apart). I think it's the same as Amondotech saying theirs has PTC...no one's torn one apart and they aren't the mfr (they buy cells from a battery mfr in china who, guaranteed, sells those cells to other customers/clients unless they have a contract limiting the design and Amondotech has paid all the NRE). I can personally only know so much by doing things myself (as with anyone). The rest I have to rely on the information of people much closer to the source of the information.
When I called Tenergy CS, I was surprised they connected me to one of their engineers/technical people who was much more helpful in answering some questions I had about their rechargable cells. True, their normal CS people don't know much, but they don't seem to BS the info and are at least willing to connect you to someone who can possibly provide an answer.

[greenLED]

Newbie! Excellent pictorial.
I wouldn't dare do that to any cells.

[JimH]

That's our Newbie - no fear of death

[Brighteyez]

Thanks for the confirmation. It's getting a little difficult to keep track of all of these, and coupled with the often 'undocumented' changes that can occur with Chinese imports in both big name brand products, and the vanity branding market, I'm starting to wonder if the information that comes forth even from the most well-intended vendors may end up differing when the next shipment comes in. Really can't blame the retailer either as they're probably often not made aware of such changes.

Originally Posted by jsr

I was told this by the owner of BatteryJunction who carries Tenergies when I was looking into Tenergy cells.

[modamag]

Thanx Newbie for the closeup and the "brave" venture.
Great Macro Pics

Now I know which parts it is that were left after the fire.

[jsr]

Originally Posted by Brighteyez

Thanks for the confirmation. It's getting a little difficult to keep track of all of these, and coupled with the often 'undocumented' changes that can occur with Chinese imports in both big name brand products, and the vanity branding market, I'm starting to wonder if the information that comes forth even from the most well-intended vendors may end up differing when the next shipment comes in. Really can't blame the retailer either as they're probably often not made aware of such changes.

I agree, and it's difficult to verify the claims and time consuming to do so, of all the various brands, etc.

Another big thanks to Newbie for taking the risk (and saving me my eyebrows and whatever else would've burned off if I tried this).

[Brighteyez]

Here, Here.
Hats off to him if he's experienced enough to do it.
Hats off to him if he's the only one foolish enough to do it.
Thank goodness we're not all so daring or there may be fewer of us ...

Very informative in either case!

Originally Posted by jsr

Another big thanks to Newbie for taking the risk (and saving me my eyebrows and whatever else would've burned off if I tried this).

[NewBie]

Actually, the white porous membrane is typically a polyolefin (or other fluorinated polymer, like UHMWPE) membrane that is designed to melt (or maybe swell would be a better word) a bit and close up it's pores in a localized shorted area. In

Molicel's secondary cells, there is an additional very high temperature plastic membrane that adds an additional safety margin, were they said the single low temp membrane had been known to fail due to temperature. The low temp was still necessary, as in a localized spot, the temperature may not reach high enough to swell/melt a higher temp membrane


Thanks for the kudos fellas.