Accidently caused a shortcircuit with my Ni-Zn cells:(

[MarioJP]

I tellin ya just don't seem to have best of luck with batteries lol.

Anyways I have a 4 AA cell holder to be used in a led project but I accidentally shorted out one of the cells and did not realize it until the spring melted right through the plastic. By the time I have realized the spring was dark grey or was completely burned and lost its form of being a spring. That particular cell was kind of hot. I Let it sit for a day only to find out the voltage now reads 0. Won't even make a connection anymore.

I even tried charging the cell directly by using other batteries as the source. The moment it started to charge it was venting immediately like just started to hiss.

No way can these cells be this fragile??

 

[VidPro]

in the Ni-Zn thread another person noted that they had too high of load, or short or something and the battery failed permenantaly also.
look at it this way automatic short protection

 

[Apollo Cree]

No way can these cells be this fragile??

Fragile?

Shorting out batteries long enough to melt stuff is generally considered to constitute mistreatment. Dying a quiet death without venting or exploding sounds like a good thing.

 

[Russel]

This thread reminds me of the signature line SilverFox uses:

"Most batteries don't die - they are tortured to near death, then murdered..."

 

[MarioJP]

Looks like it was in pairs that got shorted out as the second one that was next to the hot cell is starting to fail today. So they do die quietly and slow. Now i have 2 of these cells left. And i doubt those got shorted i think. Should of just left those in my electric toothbrush. The battery holder in the other hand is toast. How much amps are we talking about here because it did not take that long. It was fast.

 

[Apollo Cree]

It was fast.

How long? 1 second, 10 seconds, 1 minute?

 

[MarioJP]

How long? 1 second, 10 seconds, 1 minute?

That's just it. I don't know when the short started I noticed was a strange smell and that's when I looked to see. But I assuming it was less than a minute. And it looks like it was in pairs that got shorted. as both cells failed a day later.

 

[Mr Happy]

Don't short circuit batteries. Even alkaline cells can make a lot of heat if you short them out. NiCd and NiMH cells even more so.

The is one of those things to learn and remember very early on.

Keep in mind that batteries are designed to store energy, and powerful batteries are designed to release that energy fast. A charged battery is a dangerous battery. You cannot have a powerful battery without the risk of heat and fire and smoke and things melting.

 

[McAllan]

Yes a short makes a great current flow and as such it can heat a wire and itself quite considerably.

However I've not experienced a NiMH or NiCd fail like that due to a short or very high load. A few seconds short doesn't really seem to cause any harm (at least if not done too often) and even longer shorts don't make them fail like that. The capacity and their performance simply just appears to drop.

But great to hear how safe they are too. Nothing else to cause any significant danger other than the great current flow itself. But hey as a nickel based battery I really had expected it to be so.
Just wonder when they start to appear over here. Really excited to try them out myself to find out what kind of creatures they are.

 

[Mr Happy]

However I've not experienced a NiMH or NiCd fail like that due to a short or very high load.

Maybe you have safely avoided such failures, but be assured that NiMH and NiCd really can fail that way if you are incautious.

Not so long ago I was attempting to solder to an AAA cell. I applied a bit too much heat with the iron and caused an internal short. Next thing I know the cell was sizzling and bubbling and melting its shrink wrap. And that was a tiny AAA cell. Imagine what a bigger cell would do.

 

[MarioJP]

I had shorts with NiMh before in the past but Ni-Zn are totally different beasts. Never have I seen a battery fail like that. It either works really well or it doesn't work at all unlike NiMh where it gradually degrades unless it shorts.

I tried to revive the dead Ni-Zn cell directly again (of course I did this outside just to be safe) The positive electrode started to hiss and then white foam was coming out of the + terminal. The foam looks like from a furniture polish spray. Cell was not burning hot. It got warm close to becoming hot when the previous short happened in the AA holder.

After that cell was completely dead at 0V as if there was a open circuit from inside the cell. Also forgot to mention is that before the second cell failed. I remember the voltage was 0.36v and it was just jumpy. Thought my multimeter was acting up. and after awhile or couple of hours. took the readings again from the same cell and it just flat 0. I don't think internal shorts happen when it was hissing. Battery was cold while it was hissing and foaming

 

[hopkins]

Ni-Zn battery Material Safety Data Sheet. -

Carcinogenicity: Nickel has been identified by the National Toxicology Program (NTP) as
reasonably anticipated to be a carcinogen. Cobalt has been identified by IARC as a 2B
carcinogen.
Other Effects of Repeated (Chronic) Exposure: Chronic overexposure to nickel may result
in cancer; dermal contact may result in dermatitis in sensitive individuals.


http://www.powergenix.com/docs/pg-nizn-msds.pdf

 

[McAllan]

Maybe you have safely avoided such failures, but be assured that NiMH and NiCd really can fail that way if you are incautious.

Not so long ago I was attempting to solder to an AAA cell. I applied a bit too much heat with the iron and caused an internal short. Next thing I know the cell was sizzling and bubbling and melting its shrink wrap. And that was a tiny AAA cell. Imagine what a bigger cell would do.

Heat can kill almost everything. A short can either cause the heat close to the terminals or a bit away. When soldering directly on cells you're causing very intense heat directly to the call which only a very severe short has a chance of creating.
In the past I've I've soldered on both NiCd and NiMH. NiCd seemed to do OK if done fast but NiMH are very easy to kill that way. The best thing is simply to buy batteries with solder tabs or have the equipment to do the spot welding - that's the way solder tabs are attached and batterypacks assembled. Or using battery holders for those applications where that's possible because of power and space requirements.

 

[Mr Happy]

Yes indeed, I know that welded tabs are the recommended solution for battery packs -- but recommended solutions are not always available to us. After destroying a cell I learned how careful you have to be when attempting to solder to them.

My purpose in mentioning it was to illustrate how hot the cell got after it developed the short circuit.

 

[MarioJP]

Well got to be careful next time. Just confirmed that the short was in pairs. 2 out of 4 cells just failed.