Protection voltage of lithium-ion batteries

The charging and discharging process of lithium-ion batteries requires setting the upper limit of charging voltage and the lower limit of discharging voltage.

Therefore, the protection voltage of lithium-ion batteries (referred to here as lithium-ion batteries) is divided into charging protection voltage and discharging protection voltage.

For a single lithium battery, the general standard for protection voltage during charging is 4.2V, and there are also better performing lithium batteries that can be designed at 4.35V. Due to product consistency issues, the actual charging protection voltage will allow for a small floating space, such as between ± 0.05V.
The general standard for protection voltage during discharge is 2.75V. In order to use the battery more safely, some have designed the protection voltage to 3.0V. On the other hand, in order to discharge more electricity, some lithium battery manufacturers may set the protection voltage to 2.5V or 2.4V.

The protection voltage of lithium batteries is an extremely important parameter in the design of lithium batteries. In practice, we should consider the charging protection voltage as the highest voltage of the lithium battery and the discharge protection voltage as the lowest voltage. Strictly adhering to these two voltage values will not cause overcharging and discharging of the lithium battery, thus better maintaining its service life.

A lithium battery pack composed of a single lithium battery is generally referred to as a multi-core lithium battery. The protection voltage of this multi-core lithium battery is the product of the protection voltage of a single lithium battery and the number of series batteries. For example, the protection voltage of a 7.4V lithium battery is 2.75 * 2=5.5V.

The protection voltage of lithium batteries and multi-core lithium batteries is actually written on their protection ICs, and the battery operates according to the instructions of these ICs. That is to say, these batteries all have self-protection functions. When using batteries, we should carefully read the instructions and understand their self-protection methods.

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