1. Freezing
A few days ago, one of my lithium-ion batteries stopped working. The symptoms were that it wouldn't charge and wouldn't turn on my camera (the camera showed it was out of power), no matter how many times I tried. I was about to throw it away when, for some reason, I sealed it in multiple layers of absorbent paper and plastic wrap and put it in the freezer (at -18 degrees Celsius) for two whole days and nights. After taking it out, I left it at room temperature for two days, still in its packaging. Still not satisfied, I put it back in the camera and tried again. Hey, it worked perfectly! I'm sharing this with everyone; if you encounter a similar situation, you might want to give it a try!
2. Discharge
Lithium-ion batteries can be discharged by either powering on the device or by connecting a resistor. For power-on discharge, the discharge should continue until the phone immediately shuts off upon powering on. For resistor discharge, a small LED of the appropriate voltage can be connected and discharged for an extended period until the LED immediately turns off upon connection. A higher discharge current is preferable.
3. Activate
Connect a 12V AC power supply in series, and also connect a small light bulb or resistor in series between the batteries for current limiting. First, activate the battery with a small current, setting the control circuit AC current to tens of milliamps, and maintain this for 30 to 60 minutes. Then, increase the current to 1 to 2 times the battery's nominal value. For example, increase the current to 1000-2000 milliamps for a 1000-2000 milliamp, and activate for 30 to 60 minutes. During this process, carefully observe the temperature and appearance of the lithium-ion battery: there should be no overheating, smoking, bulging, or other abnormal phenomena. If the temperature is too high (above 40°C), reduce the current appropriately.
