Alternating current and direct current charging and active equalization circuit for lithium battery pack

Abstract

Provided is an alternating current and direct current charging and active equalization circuit for a lithium battery pack. The circuit comprises a cascaded battery unit, the equalization circuit and acontrol circuit; the cascaded battery unit is divided into three bridge arms A, B and C, each bridge arm includes 2 (m+1) batteries, two inductance elements are connected in the middle of each bridgearm, and the connection nodes of the two inductance elements of any one of the three bridge arms A, B and C are respectively connected to the three phases of an alternating current power supply; theequalization circuit includes a full bridge module, and the full bridge module is connected to a battery; the left side of the cascaded battery unit is connected with a large capacitor C and a directcurrent power source Udc; the control circuit is connected to the cascaded battery unit. By adopting the circuit, the battery can be connected by arbitrarily selecting an alternating current grid or adirect current grid, and can be rectified by a full bridge control circuit to be charged when connected to the alternating current grid. The battery pack can be subjected to power balance in the charging process, the rest process and the use process. The service life of the battery pack is effectively prolonged, and the safety of use is ensured.

Description

technical field [0001] The invention relates to the technical field of double-terminal charging and equalization of a battery pack, in particular to an AC / DC charging and active equalization circuit for a lithium battery pack. Background technique [0002] The development of battery technology makes it rapidly applied in various fields, among which power lithium-ion batteries have important engineering application value for promoting the development of new energy vehicles and new energy power generation, but are limited by the voltage and Capacity characteristics usually require multiple single cells to be connected in series and parallel to form a power battery pack. Due to the inevitable differences in the chemical characteristics of each battery, coupled with the influence of factors such as aging, temperature, and current, the differences in batteries gradually increase. The remaining capacity is low, seriously affecting the capacity of the battery pack and battery safe...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the defects in the prior art, the present invention provides an AC / DC charging and active equalization circuit for a lithium battery pack, by adopting an AC / DC charging circuit and an equalizing circuit in the battery management system (BMS) of the battery pack. Ensure that the monomers in the battery pack do not appear to be overcharged and overdischarged during charging and discharging, and improve the unbalanced phenomenon of the battery pack after use

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