How to Detect the Charging Loss of an 18650 Lithium Battery Pack

How to detect the charging loss of an 18650 lithium battery pack?
1. Battery consumption performance: battery voltage does not go up and capacity decreases. Measure directly with a voltmeter, if the voltage across the 18650 battery is lower than 2.7V or there is no voltage. Indicates that the battery or battery pack is damaged. The normal voltage is 3.0V ~ 4.2V (generally the 3.0V battery will cut off the voltage, the 4.2V battery voltage will be fully charged, and some have 4.35V).
2. If the battery voltage is lower than 2.7V, you can use the charger (4.2V) to charge the battery. After ten minutes, if the battery voltage has rebounded, you can continue to charge until the charger indicates that it is fully charged, and then check the full voltage.
If the fully charged voltage is 4.2V, it means that the battery is normal. It should be that the power consumption was too much in the last use, and the battery is cut off. If the fully charged voltage is much lower than 4.2V, it means the battery is damaged. If the battery has been used for a long time, it can be judged that the battery life has expired and the capacity is basically exhausted. should be replaced. Basically there is no way to fix it. After all, lithium batteries have a lifespan, not infinite.
3. If the 18650 lithium battery pack is measured and the battery has no voltage, there are two situations at this time. One is that the battery was originally good, and it was caused by long-term power loss storage. This kind of battery has a certain probability of recovery. Generally, it is activated by a lithium battery pulse. It is possible to recharge the battery several times in a short period of time by using an instrument (lithium battery charging and discharging instrument). Generally, the repair cost is not low, and it is better to buy a new one. Another possibility is that the battery is completely worn out, the battery separator is broken down, and the positive and negative electrodes are short-circuited. There is no way to fix this kind of thing, just buy a new one.
18650 lithium battery pack battery repair method principle:
1. The metal surface of the 18650 lithium battery pack that has been used for a long time will be oxidized to a certain extent, which will lead to poor contact between the mobile phone battery and the mobile phone, and the use time of the lithium battery will be shortened. Rusty substances that make the battery better in contact with the phone.
2. The low temperature can change the electrolyte inside the lithium battery pack and promote the chemical reaction of the battery that has just been frozen. The use of lithium batteries is actually a charging and discharging process. During this time, the negative and positive charges in the battery collide with each other. When the lithium battery is placed in a low temperature environment, the microstructure of the lithium film on the surface of the lithium battery and the electrolyte, as well as their interface will change significantly, resulting in a temporary inactivity inside the battery and a reduction in leakage current. So after charging again, the standby time of the phone will increase.
The cycle life of the lithium battery pack is about 600 times. If there are too many charging times, the thermal motion of the molecules will gradually destroy the microstructure of the internal molecular arrangement, and the efficiency of storing electric charges will gradually decrease.