Lithium battery active equalization system and method

Abstract

The invention discloses a lithium battery active equalization system and method. A plurality of batteries form a battery pack unit, a bidirectional DC / DC module is used for charging or discharging a single body with a large voltage difference, a working state of each DC / DC module is controllable, a circuit of the DC / DC module is independent, reliability is high, and complexity of the system is reduced; the DC / DC module is connected with a battery pack monomer through a switch array; only one monomer is equalized at the same moment, mutual influence between the circuits is avoided, a charging current is applied to the battery according to the voltage difference between the voltage value of the monomer of the battery and a set voltage, a maximum monomer charging current can reach 3-4A, an equalization speed is high, and the voltage of the monomer of the battery in each group unit is close to be consistent; and the charging and discharging current of the system is large, the voltage difference between the monomers is eliminated, equalization maintenance of the battery is completed, and the system and the method are widely applied to the fields of new energy automobile battery equalization system and second-hand battery equalization system transformation and power grid energy storage lithium battery application.

Description

technical field [0001] The invention relates to an automobile battery equalization system, in particular to an active equalization system and method for a lithium battery, belonging to the technical field of automobiles. Background technique [0002] Lithium-ion power batteries are the key core components of new energy vehicles. In practical applications, there are slight differences in the performance of battery cells due to different batches of battery production materials, or due to factors such as defects in the production process, making the battery pack The consistency of a single cell in the battery becomes poor, and the pressure difference between the battery cells becomes larger, which reduces the overall capacity of the entire battery pack and seriously affects the service life of the battery pack. [0003] The existing solutions usually use equalization technology to alleviate the battery consistency problem. The current lithium battery equalization technology is ...

AI Technical Summary

Problems solved by technology

[0002] Lithium-ion power batteries are the key core components of new energy vehicles. In practical applications, there are slight differences in the performance of battery cells due to different batches of battery production materials, or due to factors such as defects in the production process, making the battery pack The consistency of a single battery in the battery becomes poor, and the pressure difference between the battery cells becomes larger, which reduces the overall capacity of the entire battery pack and seriously affects the service life of the battery pack.

[0003] The existing solutions usually use equalization technology to alleviate the battery consistency problem. The current lithium battery equalization technology is divided into two methods: active equalization and passive equalization. Passive equalization has a small equalization current, and the equalized current can only reach tens of mAh, and can only discharge monomers with high battery voltage, it is difficult to play an application role when the battery pack capacity is large; the active equalization method, the control circuit is complicated, and many power conversion circuits need to be added, and the large Part of it can only be balanced in one direction, and the circuit cost is high, which limits the mass application of the active equalization method. Therefore, we propose an active equalization system and method for lithium batteries

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