Constant Voltage Charging Method

During the charging process, the charging voltage always remains unchanged, which is called constant voltage charging method, or constant voltage charging method for short. Since the power supply voltage remains constant from the beginning to the late stage of constant voltage charging, the charging current is quite large at the beginning of charging, which greatly exceeds the normal charging current value. However, with the progress of charging, the battery terminal voltage gradually increases and the charging current gradually decreases. When the battery terminal voltage is equal to the charging voltage, the charging current is reduced to the minimum or even zero. It can be seen that the advantage of constant voltage charging method is that it can avoid excessive charging current at the later stage of charging, resulting in the falling off of active substances on the electrode plate and the loss of electric energy. But its disadvantage is that at the beginning of charging, the charging current is too large, and the volume of electrode active material changes and shrinks too fast, which affects the mechanical strength of active material and causes it to fall off. At the later stage of charging, the charging current is too small, so that the active substances deep in the plate can not get the charging reaction, resulting in long-term insufficient charging, which affects the service life of the battery. Therefore, this charging method is generally only applicable to special occasions without power distribution equipment or with relatively simple charging equipment, such as the charging of batteries in cars, and the charging of small dry battery type batteries from No. 1 to No. 5 adopts the isobaric charging method. When the battery is charged by isobaric charging method, the required power supply voltage is about 2.4 ~ 2.8V for each single battery of acid battery and about 1.6 ~ 2.0V for each single battery of alkaline battery.