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Well I had a interesting Lithium Battery experience today, I guess that says what a nerd I am, any way I bought a laptop battery pack from the local thrift store and cut out the cells from it. What was odd, they were all flat dead, 0 volts. normally one or two will show 3 or 4 hundred mV and some times I can bring them back from the grave. But 0 volts? they acted like they were not even in the charger. so I had to do my favorite thing, I took one apart. What was Interesting, under the cap of the pos-electrode was a dome that had been connected to a fine mesh that was then connected to the electrode. from what I gathered from the arrangement, the metal dome would go up and down from gas discharge while being charged. that in turn would cause the mesh to flex and after a certain number of charges the mesh would give way due to metal fatigue. I other words after, say a thousand charges all the cells die at the exact same time. corporate planing at its finest, a real picture of the future to come. Well I thought, if I push the mesh under the the electrode until it makes contact with the dome? CONTACT it works. I had to take a very small probe that will fit in the holes in the electrode and then while the battery is connected to the charger I gently pushed on what I thought was the center, you have to do it in the blind. When the charger shows that it is charging your done. 
Zoom in on the pic to see better.
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Interesting detective work. I've come across this 'open circuit' Li cell phenomenon myself, and always thought that it couldn't be a chemical effect, it had to be a genuine open-circuit. I wondered if they had a thermal fuse (the non-resetting low-melt solder blob type) in them, or a pressure activated breakable wire. But I never really fancied dismantling one - despite taking apart plenty of other cells, including mercury ones.
What were your cells, cylindrical types like 18650 etc?
Do you think your solution will be durable long-term?
Any side effects, like higher internal resistance? -
Yes 18650, they had a white tube on the outside. Some are good as new, but I know I broke a few of the seals when I heard a phisssh sound, Right now 4.1 to 4.2V average on the good ones, but I doubt much life for the punctured ones.Comment
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it Sound like you activet the short circuit or overload protection of thes cells
they should prevent a bigger damage
i often use 18650 or 14500 cells for my Projects, i am very happy with them
better that These nimh packs and lipo cells i used before
so i plan every new Project which Needs battery power to works with 18650 or 14500Comment
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