Brief Short-Circuit LiIon Test OK?

[jayflash]

My search for "flash-amps" testing brought up old threads. I've VERY briefly shorted 16340 cells once or twice and those cells still have reasonable (for their age) capacity ten years later. They were never over-discharged and charged @ 300mA - 500mA.

Am I correct to think that severe, but brief, treatment is even better tolerated by modern LiIon cells - especially IMR123s? Some hobby uses put 18650s under considerable drain. What's the latest thinking on this? (I've been away for awhile)

Thanks.

 

[Lynx_Arc]

Not recommended at all. You can overheat lithium ion batteries causing fire or worse this is why there are protection circuitry on some cells and almost all packs.

 

[lightfooted]

Something to keep in mind is that modern cells have significantly more energy than those of olde...so while a "brief short" of an older cell may result in some heating, doing so with a newer one of as much as 100% more capacity...is likely to simply melt everything around it into a puddle. Yes, I mean the metal bits too.

 

[WalkIntoTheLight]

Definitely not recommended. But if you keep it to under 1 second, you might get away with it. It's also possible that there could be some internal damage that is not immediately evident, but might cause safety problems in the future.

That said, if the battery still tests okay (full capacity, no heating during charging, maintains a full charge, etc.), it's probably okay. But the safety might drop from 99.9999% safe to 99.99% safe. 100x less safe, even though it's still very safe. That's just an example, I have no idea what the real numbers are.

 

[jayflash]

The possible dangers are well understood, which is why the DMM probes touch the terminals for only ~0.5 seconds or less. Maybe I missed the info, but I couldn't find anything definitive on Battery U's site. I'd appreciate direction to Bat U's info on the subject if it exists. I'm interested in longevity facts as I know what the safety concerns are.

I have learned that modern 16340 IMR cells will discharge around 20 amps, which is far more than a D sized alkie. That's quite a hike in technology. Thanks for the input.