Active balancing circuit of power Li-ion battery module and balancing method thereof

Abstract

The invention provides an active balancing circuit of a power Li-ion battery module and a balancing method. The active balancing circuit of the power Li-ion battery module and the balancing method belongs to the technical field of motor automobile battery management. The balancing circuit comprises a Li-ion battery group, a charging-discharging switching group unit, a charging-discharging bus unit, an energy transferring circuit and a balancing controlling device, wherein the Li-ion battery group is connected with the charging-discharging bus unit by the switching group unit. Two sides of the energy transferring circuit are further connected with the charging-discharging bus unit. The balancing controlling device is connected with the Li-ion battery group, the charging-discharging switching group unit and the energy transferring circuit. Voltage of a Li-ion single body battery is monitored in real time, the Li-ion single body battery requiring the charging-discharging of the switching group unit is controlled and the energy transferring circuit is controlled, thus the charging-discharging of the selected Li-ion single body battery is achieved. Defects of the existing power Li-ion battery module are overcome. The active balancing circuit of the power Li-ion battery module and the balancing method have the advantages of being simple to control, large in balanced current, high in balancing efficiency and low in cost.

Description

technical field [0001] The invention belongs to the technical field of electric vehicle battery management, and relates to a power lithium-ion battery module charging and discharging equalization circuit and a control method thereof. Background technique [0002] The power battery module for electric vehicles is composed of single lithium-ion batteries connected in series. Due to the inconsistency of the performance of the single lithium-ion batteries, the voltage of the single cells will be inconsistent during charging and discharging, which will affect and restrict the charging and discharging capabilities of the entire battery module. . As long as a single battery reaches the charge and discharge voltage limit during work, the entire battery module must stop charging and discharging, otherwise the single battery will be overcharged or overdischarged, seriously affecting its life. The effective balance of the single battery can better play the battery performance and prol...

AI Technical Summary

Problems solved by technology

Capacitor equalization current is not easy to control, and switching tube voltage division also makes the equalization effect not obvious; inductance equalization can only be carried out between adjacent single cells, the structure is complex, and the equalization speed is limited; transformer equalization has problems of magnetic saturation and complex structure; Existing bidirectional DC-DC balance also has various design and efficiency defects

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