How Dangerous Might a Puncture to an Ebike Lithium Polymer Battery Be?


10 kW
Feb 23, 2015
Laramie, WY
Pin hole size punctures and short shallow ex-acto knife slits are not a cause for much immediate concern but if the punctures are left uncovered they will lead to less cell capacity and eventually cell failure. If the holes are covered with hot glue soon after the cut the cell capacity does not degrade. Apparently water vapor entering the cell is the active deteriorating agent.

I was wondering what a bigger quick puncture might do to a pouch and devised a way to test this safely.

10 kW
Apr 28, 2023
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Yes, I fired a `12ga slug into a 12Ah LiPo pouch charged to a top out of 4.09 v. Now that resulted in a rapidly made 1” diameter hole thru the pouch severing some dendritic copper wires and short circuiting other dendritic wires. Explosions happen when an energy wave propagates so fast that material/energy flies from the wave front. Nothing quite that spectacular here — this is not prima cord 19,000 ft/sec.

But from an energy standpoint the cell had some 3.9 v X 12 aH = 48 watt-hrs of energy to dissipate. Suppose this energy is dissipated in 10 sec. The rate then would be 48watts hrs = 48 x 360 faster than a one hour dissipation which is equivalent dissipation of a QS 3000 motor just consuming 17,280 watts/sec for 10 sec. The motor will not burn up at this rate for 10 sec. It may be warm.

The cell was out of electrical/chemical energy in maybe 10 sec - no explosion - but the alum cell covering melted and the char pile was hot. You could move out of the heat unless somehow restrained.

There would be a potential for flesh burns.
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They dont explode at all.

.....they dont have a " TNT EQUIVALENT " energy output.

Ok so for real they actually do..