1. Lithium-ion battery activation method:
1.
Try 2x or 3x the voltage to reactivate it. Overvoltage refers to: the battery is generally 3.7-4.7V, you can use 6V, otherwise, you can use 9V.
All batteries and wires available, preferably monitored with a multimeter. If you have no experience related to maintenance, this is exempt. Connect the available batteries in series and charge the batteries with positive to positive and negative to negative wires.
2. Freezing method
If it cannot be loaded, wrap it in paper and then in a plastic bag. Place in the refrigerator for 1 week and take out for 2 days. Connect the device and if power may appear, charge it immediately until fully charged.
3. Wiping Method
For low battery life that is not a serious problem, use a wiper propre to gently wipe the metal contact surface between the battery and the device after a long time. During use, the metal surface of the battery will have a certain degree of oxidation, resulting in poor contact and reduced battery life. Using an eraser can erase the oxide layer on the surface to improve contact between the battery and the device.