Lithium iron phosphate battery pack charging method

Date:Oct 25, 2019

(1) Constant voltage charging method: During the charging process, the output voltage of the charging power source is kept constant. With the change of the state of charge of the lithium iron phosphate battery pack, the charging current is automatically adjusted. If the specified voltage is constant, the full charge of the power battery can be ensured, and the gassing and water loss can be minimized. This charging method only considers the single state change of the battery voltage and does not effectively reflect the overall charging condition of the battery. Its initial charging current is too large, which often causes damage to the power battery. In view of this drawback, constant voltage charging is rarely used.

(2) Constant current charging method: The charging current is kept constant by adjusting the output voltage throughout the charging process. Keeping the charging current constant, the charging rate is relatively low. The constant current charging control method is simple, but since the acceptable current capability of the lithium battery pack is gradually decreased as the charging process progresses, the power receiving capacity of the power battery is lowered and the charging current utilization rate is greatly reduced. The advantage of this method is that the operation is simple, convenient, and easy to implement, and the charging power is easy to calculate.

(3) Constant current constant voltage charging method: This charging method is a simple combination of the above two. The first stage uses a constant current charging method to avoid excessive charging current at the beginning of constant voltage charging. The second stage uses a constant voltage charging method to avoid overcharging caused by constant current charging. Like any other sealed rechargeable battery, the lithium iron phosphate battery pack must be charged and not overcharged, otherwise it will easily damage the battery. The lithium iron phosphate battery generally adopts a charging method of first constant current and limited voltage.

(4) Chopper charging method: Charging is performed by chopping. Under this method, the current of the constant current source is unchanged, and the switching tube is controlled to be turned off for a period of time and then turned off for a period of time, and the cycle has the advantage that when the battery is charged by an external circuit, Ion generation inside the battery requires a certain response time, and if it is continuously charged, it may reduce its potential. After charging for a period of time, adding a turn-off time allows the ions generated by the two poles of the battery to 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 battery. Charging effect.

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