Two Methods to Fix a Lithium-ion Battery Which Could Not be Charged
(for the battery which is not fully dead)
A lithium-ion battery could be recharged for several hundred times.
On google:
I had a lithium-ion battery which was in a camera for quite long time and had never been used for that period of time. When I was trying to take a picture, it did not power the camera. I put it in a charger, the charger would not charge it. The volt meter reading was 0 v.
For a lithium-ion battery, there is a voltage threshold, below which the charger consider it as a dead battery and would not charge it. So the key is to let the battery stay above the threshold. In a commercial lithium-ion battery (not the bare 18650 lithium-ion battery etc.) there is a protecive charging and discharging circuit which limits the voltage to be charged and discharged. https://batteryuniversity.com/article/bu-409-charging-lithium-ion#:~:text=Figure%201%3A%20Charge%20stages%20of%20lithium%2Dion&text=The%20advised%20charge%20rate%20of,C%2Drate%20with%20little%20stress.
But it happened in my case, the voltage fell into zero.
Here is a bad or "bad" battery, I took it apart:
The protective charging board:
The method 1 I'm using was known on the web for a long time. https://www.youtube.com/watch?v=OHaUa6tRBdo
It used the same type of battery with the same voltage and high current to charge the "bad" battery for a very short time. This will bring the "dead" battery above the charging threshold.
Method 1. Use the same type of battery, 7.2 v.
The the "bad" battery read 0 v, which could not be charged.
Using alumium foil to make two piece of "wires" so the two battery could be connected:
Put the two pieces on two terminals of the "bad" battery:
Put the good battery on top of two aluminum pieces:
Press an hold a fully charged battery on top of the "bad" battery for 10-15 seconds, measure the voltage, now it was 6.79 v:
Put it on the charger:
After 37 minutes, it was 7.61 v:
After 1 hour 34 minutes, it was fully charged:
Its voltage was 7.99 v.
Method 2. Use a battery with a different voltage, I used 4 AA NiMH batteries in series (they should be around 4.8 to 5.5 v):
Put the positive and negative wires of the AA batteris on the terminals of "bad" battery for around 5 seconds:
Then, the reading of the "bad" battery was now 7.2 v (no picuture of 7.2 v, but I wrote down the voltage on a piece of paper I wrapped on the battery several months ago):
It could be charged with the charger.
Note: these metheds could only be used for a battery which is not totally deteriorated or dead. If you used it frequently, charged it frequently over several hundred times, the battery is really dead and the life of the battery could not be rejuvenated by charging any more.
For example, this battery was 0 v, but after I used the method 1 above, the voltage reading was still 0 v.
