The harm of overcharge and overdischarge to lithium batteries

There are several operations that can cause permanent damage to lithium batteries, two of which are overcharging and overdischarging. You may ask, what are overcharge and overdischarge, what harm do they do to lithium batteries, and how to avoid overcharge and overdischarge of lithium batteries in daily use? Below is the answer for everyone!



1. Overcharge means that when the lithium battery is overcharged, the charging working voltage of the battery exceeds the set working voltage. For example, a rechargeable battery is rated at ±. That is to say, if the maximum operating voltage is higher than 9V, it is called overcharge. How does overcharging harm rechargeable batteries.

2. During the overcharging process, the battery voltage will increase rapidly with the expansion of polarization, resulting in irreversible changes in the structure of the positive active material, resulting in the dissolution of the lithium battery electrolyte, generating a large amount of steam and releasing a large amount of heat value , greatly increase the temperature and air pressure of the battery, dissolve or close the external diaphragm, cause the positive electrode of the battery and the positive electrode material to contact short circuit failure, and there are safety hazards such as explosion and fire

2. Hazards of overdischarge motor of lithium battery

1. Over-discharge refers to the process of charging and discharging after the working voltage reaches the rated current and is still discharging. For example, if the rated charging and discharging working voltage of the ternary lithium battery is lower than the rated charging and discharging working voltage, it is over-discharged. How does excessive discharge harm rechargeable batteries?

2. When the battery discharges the externally stored power and the working voltage reaches a certain value, redischarging will cause the rechargeable battery to over-discharge. Excessive discharge of the battery will have a devastating adverse effect on the battery, especially power loss or repeated discharge under high current will cause greater damage to the battery. Generally speaking, over-discharge will increase the air pressure of the battery, destroy the intersection of positive and negative active materials, dissolve the electrolyte of the lithium battery, accumulate lithium in the negative electrode, and increase the resistance. Even if the battery is only partially serviced after charging, there will be a significant decay factor in the volume

3. How to avoid overcharging or overdischarging the battery in daily use

1. It is used in conjunction with the lithium battery protection board (BMS) for lithium batteries. The lithium battery protection board can charge and maintain the rechargeable battery. The smart version can also set the working voltage of battery charging and discharging, which can better maintain the rechargeable battery

2. Lithium battery chargers used in supporting facilities do not use fast charging

3. When the battery voltage reaches the working voltage set by the lithium battery protection board, the lithium battery protection board will turn off the power to maintain the rechargeable battery, but the lithium battery will decrease and the working voltage will increase, and it will be slightly higher than the lithium battery protection board setting working voltage. This time will no longer apply. Continuous use will inevitably cause damage to the rechargeable battery.

We can see that overcharge and overdischarge are harmful to lithium batteries! To avoid them, you need to purchase qualified lithium batteries with protection, and pay more attention to avoid overcharging and overdischarging during use!

Post time: Dec-02-2022

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