Re: dead battery

Allan Adler <ara@xxxxxxxxxxxxxxxxxxxx> writes:

Allan Adler <ara@xxxxxxxxxxxxxxxxxxxx> writes:
Thanks for the helpful suggestions on how to open the battery. I looked
at the materials safety data sheets for MnO2 and KOH, which are in the
battery. Does anyone worry about hazards of working with them?

I was informed that one can recharge these alkaline batteries, even though
the manufacturer advises against doing so.

I should perhaps explain that I got interested in the battery as a result
of keeping my promise to purchase a multimeter. I didn't buy batteries for
it because I was outraged that AA alkaline batteries cost so much. They get
cheaper in quantity, but I don't need a dozen AA batteries and may not for
some time. So, I went home and decided to use whatever batteries might be
lying around, which led me to the dud I'm presently considering dissecting.

I have a couple more. I know one is supposed to use a fresh battery in
the multimeter (Radio Shack Cat. No. 22-223) but, for the present purpose
of measuring connectivity on a mouse breadboard, even an old battery with
a little life left in it should be adequate. I have a couple more old
batteries to try out on it.

The battery turns out not to have been dead. I was stupidly measuring
resistance with the dial set to the AC voltage on the multimeter. However,
the questions raised by the prospect of having a dead battery to study are
sufficiently interesting that I will keep thinking about it. For example:
(1) When you recharge an alkaline battery and it explodes, why does it
explode? Is it because of a build up of hydrogen gas from action of
KOH on the Zn powder?
(2) Whatever the reason, the amount of gas (whatever it is) built up is
limited by the strength of the steel jacket of the battery. Suppose you
put the battery inside a tightly fitting steel container with much greater
strength and recharge it. The outside container will raise the threshold
for the battery to explode, even if the battery jacket itself suffers some
damage. So, that changes the question to this: what is the maximum pressure
that can be built up by recharging the battery if it is placed in a
sufficiently strong container? Strange as it might sound, the tendency
of the battery to pop when recharged might be a safety feature which
releases the gas and thereby prevents a much larger explosion.
(3) Is there any online account of the details by which Gahn, in 1774,
first isolated manganese from manganese dioxide by reducing it with
carbon?
(4) Although various websites describe the chemicals that are supposed to
be in an alkaline battery, in fact there should be more compounds due to
reactions among these chemicals. The most important ones are described as
part of the working of the battery, but is there any complete inventory
of all the chemicals that can be found in a battery? Also, is there a
book on this kind of thing?
--
Ignorantly,
Allan Adler <ara@xxxxxxxxxxxxxxxxxxxx>
* Disclaimer: I am a guest and *not* a member of the MIT CSAIL. My actions and
* comments do not reflect in any way on MIT. Also, I am nowhere near Boston.
.

Loading