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i'm not doing anything related to physics, but i'm just curious : What really happen when i short circuit an alkaline battery ? some article in the net shown that fire/explosion can be happened when short circuit the battery. How can this happen? coz i got some article said that there is an 'internal' resistance of the battery that prevent very high current is drawn (exceed the maximum current), so i think this become the safety tool , so current or temperature won't be a problem.

But why can still produce fire or explosion ? And why the manufacture of the battery (like for example some of AA alkaline) doesn't provide info about maximum c rating or maximum current to be drawn (so where can i find it?). Ussually only Voltage and capacity(mAH) is printed. Is that kind of info is not important so it's ignored. Sometime the mAH is not even printed on AA batery. I can only see it on lipo or nimh batt.

Thanx

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1 Answer

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I've just sacrificed an AA manganese alkaline battery to the cause of physics.

When I first shorted the battery it produced a current of about 9.5 amps, which I thought was actually pretty impressive. However over the course of 30 seconds the current dropped to around 5 amps. The battery got pretty warm, though I don't think it would have set fire to anything and it didn't explode. The power generated was around 7.5 watts, so it isn't huge, though the power is concentrated in a fairly small area.

I'd be careful about doing this to a bigger battery. Larger batteries will have a lower internal resistance, and given how much current an AA battery produces I can well believe you could heat a bigger battery to the point where it becomes dangerous.

I'vd be very very careful about trying this with batteries that have a particularly low internal resistance like lead-acid or nickel-cadmium batteries!

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Hi John, thanx for doing that experiment, that's very kind of you. I was afraid doing that coz i don't want the batt to burst into my face lol. So the alkaline AA 1.5V battery won't actually explode :-), i won't try it with bigger battery (or my rc car -lippo battery) for sure. – andio Jun 22 '12 at 8:46
I checked the battery manufacturers web site first, and that assured me that an AA battery was very unlikely to explode. Still, I stood well back while I was doing it :-) – John Rennie Jun 22 '12 at 9:05
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I've set stuff on fire by accidentally shorting a D cell NiCd. Yikes! – dmckee♦ Mar 21 at 3:27
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@dmckee: I'm part of a robotics team of my institute (for ASME SDC 2013). Now, we use Lithium polymer batteries. Short these, and they explode. No intermediate fire stage, just boom. And we have some rather large LiPo batteries in the lab which we use regularly. I've seen a large lead acid battery catch fire, but I've never been (mis)fortunate enough to see a LiPo exploding :S – Manishearth♦ Mar 21 at 12:47

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