The pictures in posts 7 and 11 are signatures - they might as well have "dendrite" written all over them, because that's what you're seeing. A dendrite (chemically-caused short) growing in the battery, shorting it out. The short burns out (it's only a tiny crystal) and the voltage is around where it was before the short (or even a little higher).
The auto industry is spending billions (that's a "b", not an "m")trying to find out exactly why lithiums do this, so they can make electric cars with lithiums - and no $5,000 "we may have to pay it" tag on the car. NiCds work (hybrid cars use them), but lithiums would work a lot better - except for the dendrite problem. (Imagine accelerating to avoid a fatal accident just as your battery shorts. Wrongful death suits from causes that were known years ago tend to treat money by the long ton, not by the dollar. There's no cost/benefit ratio, because the auto maker would lose. Once they get that problem solved, we'll see dendrite-proof batteries in phones - probably for more money even if it costs 3 cents to fix the problem.)
09-03-2016 05:03 PM