Constant current charging means that the charging current does not change during charging. Constant current charging is to charge the battery with a constant current. When the battery is nearly full, continuing to use this method can easily lead to overcharging or difficulty in filling the battery.
Constant voltage charging means that the battery voltage does not change during charging. Constant voltage charging is controlled by charging the charger with a constant voltage and controlling the charging by the voltage difference from the battery. However, when the battery capacity is low, excessive charging current may cause damage to the battery or shorten battery life due to excessive pressure difference.
Therefore, constant current charging and constant voltage charging should be used in combination. Later, more and more people found that the best way to charge lithium-ion batteries is three-stage charging.
Three-stage charging refers to turbulence, constant current, and constant voltage charging. Trickle charging refers to charging the battery with a very low charging current at the beginning (at very low capacity). Trickle charging is used to precharge (recovery charging) a fully discharged battery unit.
Chargers with three-stage charging function generally adopt such a charging procedure:
2. Constant current charging - When the battery voltage rises above the trickle charge threshold, increase the charging current for constant current charging. When the constant current is charged, the battery voltage is detected. When the battery voltage is close to the cutoff voltage (for the cutoff voltage of the lithium battery, the discharge cutoff is 2.7V, and the charge cutoff is 4.2V. No matter which reason caused, once exceeding these two voltages, the battery will be damaged.), constant current charging is over.
3. Constant voltage charging - When the battery voltage rises to 4.2V, the constant voltage charging phase begins. At this time, the charger will detect the charging current. According to the saturation degree of the battery, the charging current will gradually decrease from the maximum value as the charging process continues. When the current drops below the threshold (usually 0.01C), the charger is cut off. The output is considered to be charging completed. Here the C is a representation of the battery's nominal capacity against the current, such as the battery is 1000mAh capacity, 1C is the charging current 1000mA.
This is a kind of care for the battery. The trickle charge uses a soft start method to slowly increase the current, protect the charger and the battery, and the constant current is charged by a constant current to ensure the charging speed. When the battery is almost full, the constant voltage is charged. The charging current will gradually decrease, so that the battery can reach the full charge as much as possible. Three-stage charging is currently one of the most advantageous ways to charge a battery.
This charging method also answers the question of what parameters the charger uses to determine that the battery is fully charged.
Lithium-ion batteries are more common on the market today. The lithium battery is characterized by no memory effect, and it is used with charging. The disadvantage is that it is overcharged and over-discharged. Once overcharged and over-discharged, the battery can't be used. At the high-end charger, the three-stage charging design changes the charging mode by detecting different parameters of charging to achieve better protection of the battery.
Currently, all XTAR chargers have this feature. If you have any additional comments or questions, please leave your comment below. I am very happy to discuss this with you.
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