The best charging current of lithium battery

The "lithium battery charging current" in the daily expression is for the charging current of the lithium battery in the fast charging phase during charging. As a dynamic process, the charging current of the lithium battery is actually divided into three stages. .

1. Optimal current during pre-charging: When the initial/no-load voltage of the lithium battery is lower than the pre-charge threshold, the first step is to go through a pre-charging stage. For a single lithium-ion battery, the threshold is generally 3.0V. At this stage, the pre-charge current is about the next stage - about 10% of the current in the constant current charging phase.

2, the best current when constant current charging: the so-called constant current is the current is constant, the voltage gradually rises, at this time into the fast charging phase. Most of the constant current charging current is set between 0.4 and 0.6C, which can be understood as 0.5C, that is, it can be filled for about two hours without considering other factors. The reason why 0.5C is chosen is because this current is a good balance between charging time and charging safety.

3. Charging current during constant voltage charging: For a single-cell lithium-ion battery, when the battery reaches a certain voltage value, it enters a constant voltage charging. This voltage value is generally 4.2V. At this stage, the voltage does not change. Decrease; this current reduction is a sequential decrement process. Most lithium battery protection selects 0.01C as the termination current, which means that the charging process enters the end state. Once charging is complete, the charging current drops to zero.

The core of the best charging current of lithium battery is the current design during constant current charging. It should be emphasized that most portable lithium batteries are better designed to charge 0.5C. For example, the conventional capacity of 18650 lithium battery is 1800-2600mAh. Select 1A charging, and the magnification type is 1200-1500mAh, and the charging current of 0.5C is 0.7A.

The maximum charging current of a lithium battery is strictly determined by the structure of the battery. Therefore, each lithium battery manufacturer has different idea on this regulation. Some settings are 0.6C, and the highest specification for portable lithium batteries is 1C.

Of course, the current design of pre-charging and constant-voltage charging cannot be ignored. In the two processes, if the initial voltage is not lower than the pre-charge threshold of 3.0V, there is no pre-charging process. In general, there is a process of pre-cooking and sports rest before and after the constant current charging process that is beneficial to the long-term use of lithium batteries.