When that white crystalline material forms on th ends of the cells and the impedance goes high and they become useless. What is that substance and how harmfull is it ? Is it the same process, in effect, that renders lead-acid cells uselss - a build up of an insoluble salt so the ions cannot pass to/from the lead to the electrolyte?
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The cells tend to leak if left discharged for a long period. How harmful would depend on what you plan to do with it. Its not good to eat and may kill you, pollute the environment, etc.. Cadmium is very poisonous, nickel is poisonous, they may contain small/trace amounts of mercury as well.
I don't know the chemistry of nicads, but do know they are radically different from lead acid, so a different failure mechanism might be at work.
Most of the cells I have experience with (back in the day) short internally, If left in that condition, over time, they leak, or just corrode from the inside out. Cells that have an internal short can often be rejuvenated by burning the short out with a discharge of heavy current through it. We used to build power supplies that would charge a cap to dump energy into the short for that purpose.
Throw them out and get new rechargeable's. Once they leak, they've had it.
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I hope you are able to reply to this message. In the event you touched that leaking chemical, you will die within 12 hours or less. Its absorbed thru the skin and eats a hole thru your brain, eventually devouring your entire brain. If you are still able to read this message, you may no longer be able to comprehend it because your brain is partially eaten away. I'd tell you to contact a doctor, but it's too late. There is no way to stop this brain decay. However, there is a possible light at the end of the tunnel. One out of 100 people do survive. They have little if any remaining brain matter, but there is enough left to remind them to breathe and keep their heart beating, Most of them end up in Texas and join the rodeo. However one of them went to Texas and later moved to Washington DC to become the president of the United States. His name is George W. Bush. Doctors have evaluated this man and found little working brain matter. They all said it's a miracle he is alive.
Good Luck You need it !!!
BAD IDEA! The cadmium in them is very toxic. That's why you should be careful about those crystals from a leaky one, and also why you should never "throw them away", but dispose of them properly as toxic waste.
NiMH use a different chemistry, and are nowhere near so bad.
Isaac
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Googling around , the electrolyte in NiCads would seem to be potasium chloride and the white crystalline buidup is probably just potassium carbonate.
Please, never THROW OUT any batteries. Take them to Radio Shack or your city haz-mat center so they can be recycled. It scares me to consider all the batteries that get thrown in the trash, which then go on to leach their toxic substances into groundwater.
Be
What about the plain carbon acid flashlight batteries? Are they bad to dispose? I dont think recyclers even take them, or the common alkaline batteries?
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