1, constant current constant voltage charging method
This charging method is a simple combination of the above two. In the first stage, constant current charging method is adopted to avoid excessive charging current at the beginning of constant voltage charging. In the second stage, constant voltage charging method is used to avoid the phenomenon of overcharging during constant current charging. Lithium iron phosphate battery pack and any other sealed rechargeable battery, to control the charge, can not overcharge, otherwise it is easy to damage the battery. Lithium iron phosphate batteries generally use the first constant current and then limited voltage charging method.
2. Chopper charging method
The chopper method is used for charging. Under this method, the current of the constant current source is unchanged, and the switching tube is controlled, so that it is turned on for a period of time and then turned off for a period of time, and the cycle is repeated. The advantage of this method is that when the battery is charged through the external circuit, the ion generation inside the battery needs to have a certain response time, and if it is continuously charged, it may reduce its capacity potential. After charging for a period of time, adding a turn-off time can make the ions generated at the two poles of the battery have a diffusion process, so that the battery has a \"digestion\" time, which will greatly increase the utilization rate of the battery and improve the charging effect.
3, constant voltage charging method
During the charging process, the output voltage of the charging power supply remains constant. With the change of the charging state of the lithium iron phosphate battery pack, the charging current is automatically adjusted, and if the specified voltage constant value is appropriate, it can ensure the complete charging of the power battery, and minimize gas and water loss. This charging method only considers the change of the battery voltage, which is a single state, and can not effectively reflect the overall charging status of the battery. Its initial charging current is too large, often causing damage to the power battery. In view of this shortcoming, constant voltage charging is rarely used.
4, constant current charging method
During the whole charging process, the charging current is kept constant by adjusting the output voltage. Keeping the charging current unchanged, its charging rate is relatively low. The constant current charging control method is simple, but because the acceptable current capacity of the lithium battery pack gradually decreases with the charging process, to the late charging period, the power battery's ability to receive electricity decreases, and the charging current utilization rate is greatly reduced. The advantages of this method are simple operation, convenient, easy to implement, and easy to calculate the charge amount.
The charger of lithium iron phosphate battery is different from ordinary lithium battery. The maximum termination charge voltage of a lithium battery is 4.2 volts; The lithium iron phosphate battery is 3.65 volts. When the lithium iron phosphate battery is charged, it is a balanced charging board connected to the line, generally from both ends of the direct series overall charging, the charger voltage is greater than the battery voltage. The voltage of each single cell is detected by the wire, which is equivalent to a parallel voltage regulator, and the charging voltage of the single cell will not exceed the voltage regulator value, while the other single batteries continue to charge through the regulator bypass charging.