Series battery monomer constant-voltage circuit and control method thereof

Abstract

The invention discloses a series battery monomer constant-voltage circuit which comprises batteries and a direct-current power supply, two ends of each battery are connected with a battery constant-voltage unit in parallel, and all the battery constant-voltage units are connected to a control unit for controlling the states of the constant-voltage units. The feedback positive electrode end of eachbattery constant-voltage unit is connected with the positive electrode of the direct-current power input, the feedback negative electrode end of each constant-voltage unit is connected with the negative electrode of the direct-current power input, and the control unit controls the state of the constant-voltage units in the mode that the overall constant-current charging and discharging steps of the battery can be achieved. Meanwhile, a constant-voltage charging step is carried out on a single battery; and in addition, in the constant-voltage working step of a single battery, redundant energyis fed back to the direct-current power supply process. The invention also discloses a control method of the series battery monomer constant-voltage circuit. According to the invention, under the state that the batteries are connected in series, the overall constant-current charging and discharging step of the batteries is realized, and the constant-voltage charging step of a single battery is realized.

Description

technical field [0001] The invention relates to the technical field of battery charge and discharge control circuits, in particular to a constant voltage circuit of series battery cells and a control method thereof. Background technique [0002] In the lithium battery formation / capacity separation process, the battery needs to be charged / discharged with a constant current first. When the battery is charged / discharged to a certain voltage with a constant current, the battery needs to be charged / discharged with a constant voltage. [0003] At present, the conventional solution is to charge / discharge a battery with constant current and constant voltage by one channel, but due to the differences of different channels, it is easy to cause battery consistency problems. It was then proposed to connect batteries in series and use the same channel to charge / discharge them. [0004] Because after the batteries are connected in series, when the battery is charged / discharged, the curre...

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Problems solved by technology

[0004] Because after the batteries are connected in series, when the battery is charged / discharged, the current flowing through each battery should be equal, but due to the difference of the batteries, this will cause some batteries to enter the constant voltage step first, and others The battery is still in the constant current step. After entering the constant voltage step, the current flowing through the battery will decrease, while the current of the battery in the constant current step will remain unchanged, which creates a contradiction.

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