A battery pack bidirectional equalization charging and discharging circuit and its charging and discharging control implementation method

Abstract

The invention discloses a bidirectional equalization charge and discharge circuit of a battery pack and a charge and discharge control realization method. The bidirectional equalization charge and discharge circuit of the battery pack comprises a battery pack composed of serially-connected batteries. The bidirectional equalization charge and discharge circuit also comprises bidirectional equalization circuits each arranged between each battery and an energy bus. The circuit structure is simple, the switch tube quantity is small, the switch tubes adopt a PWM control mode, and the control is simple. Energy can flow forwardly and backwardly. With the adoption of the charge and discharge control realization method of the bidirectional equalization charge and discharge circuit of the battery pack, synchronous rectification can be achieved by the switch tubes, and the conversion efficiency is improved.

Description

technical field [0001] The invention relates to the field of battery charging circuits, in particular to a bidirectional equalizing charging and discharging circuit for a battery pack and a method for realizing charging and discharging control thereof. Background technique [0002] With the intensification of environmental pollution, the strengthening of people's awareness of environmental protection, and the increase of national investment in improving environmental policies, more and more people pay attention to green and environmentally friendly power lithium batteries. There are a wide range of applications in various fields. In use, when the required voltage is higher than the basic voltage of a single lithium battery, multiple lithium batteries are usually connected in series to form a series battery pack. Due to differences in production processes and material properties, lithium batteries are prone to performance differences during use, so there will be potential di...

AI Technical Summary

Problems solved by technology

Due to differences in production processes and material properties, lithium batteries are prone to performance differences during use, so there will be potential differences between these series-connected batteries; When the voltage of some batteries reaches the expected voltage value, some batteries may not reach the expected value. Therefore, when charging the battery pack in series, the battery may be overcharged or undercharged. When discharging the battery pack in series, it may be The battery is over-discharged or the discharge is limited

[0003] In order to solve the above problems, the active equalization method is usually used for equalization, and the active equalization technology is mainly based on charge equalization, which is ignored when the battery is discharging, and is limited by factors such as volume, temperature rise, and cost, and the equalization current is generally low. It’s not very big. Only charging equalization technology can’t solve the various impacts caused by battery differences during discharge. The small equalization current limits the equalization speed, and even fails to achieve the equalization effect, which can’t improve the battery difference.

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