123 cell protection anatomy revealed

[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! oo:
Thanx !! Very interesting ...
bernie

 

[jsr]

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]

:thanks: 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.

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 :twothumbs

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

 

[jsr]

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!

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.

 

[picard]

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

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

yeah, I really thought there were a dozen pixxies working hard pedaling stationary bicycles to generate power.

 

[NewBie]

Okay, instead of the Energizer/Surefire cell shown above, some have said the Duracell was identical. Well, it isn't.

It has a few of the same basics and that is where things depart:

 

[SilverFox]

Hello Newbie,

I can't seem to make out the vent spike that Duracell refers to on their exploded view. Is it there?

A question comes to mind... Are hundreds of contact points in a friction fit better than a single welded point?

Tom

 

[Size15's]

Excellent thread! Thank you for making CPF great! :goodjob:

 

[chimo]

Newbie, thanks for another great disection. :goodjob:

A question comes to mind... Are hundreds of contact points in a friction fit better than a single welded point?
Tom

One benefit of this implementation if that the current should be more evenly distributed across the grid structure. It is also possible that this provides a better heat transfer to the top cap for thermal activation of the PTC.

Paul

 

[NewBie]

Hello Newbie,

I can't seem to make out the vent spike that Duracell refers to on their exploded view. Is it there?

A question comes to mind... Are hundreds of contact points in a friction fit better than a single welded point?

Tom

I see no vent spike.


There is a "springyness" to the hundreds of individual contact points, which would be alot like having the tailcap battery spring in many flashlights, but hundreds of redunant ones.


I did notice the PTC in the Duracell battery showed no blemishes from being "overly" crimped like I saw in the SureFire/Energizer cells.

 

[NewBie]

Though I do recall reading that the typical vent is designed to rupture at 40 PSI.

 

[NewBie]

Due to some recent events of exploding 123 cells, I took some more pictures for another thread, but I'm going to also put them here, so everything is also in one concise thread.

Mod/Admin, if it is an issue, please holler.

-------------


Well, decided to take some more pictures for folks of the button top and it's construction on the SureFire/Energizer and Duracell batteries:

I also ran another test, with a Duracell 123 that I cut open, and dropped in some water, at times it made more bubbles than you see in the picture, but that is about all that happened. It may be due to the limited rate at which the liquid water can actually enter into the tightly wrapped cell, which would be much different than a moisture filled cell that heats up...

Please folks, do NOT EVER try any of the stuff I am showing you, I've seen some of these cells violently throw flames and hot molten material like a rocket engine. I have some special 1/2" thick plexiglass that I do all this stuff behind, forced ventilation in an open area, and thick welders gloves, and I still wear a full face chemical shield and sealed goggles, and a few other safety precautions.

 

[cy]

very interesting info...

 

[chimo]

More great pics! Is that a solder blob on the button?

Paul