Active equalizing system and equalizing method for power lithium ion battery pack

Abstract

The invention relates to an active equalizing system and an active equalizing method, in particular to an active equalizing system and an active equalizing method for a power lithium ion battery pack. The active equalizing system comprises a battery module (1), a matrix control circuit (4), a DC / DC (Direct Current to Direct Current) unit (6), a PWM (Pulse Width Modulation) control unit (5), a main control unit (3) and a voltage temperature sampling unit (2); and by control on the DC / DC unit (6) and the matrix control circuit (4), the charging and discharging direction of a transformer T1 is changed and functions of upper limit equalizing, lower limit equalizing and energy compensation on electrical quantities of unit cells in the battery module (1) are implemented. The active equalizing system and the active equalizing method have the following advantages that (1) due to the adoption of a low-loss equalizing technology, service life is prolonged; (2) the current equalizing capacity of a large current equalizing technology reaches over lOA; (3) due to the adoption of a bidirectional equalizing technology, direct bidirectional energy transfer between one random unit cell in the battery pack and the battery module can be implemented; and (4) the active equalizing system adopts a distributed design and has a simple and practical structure and very good expandability.

Description

technical field [0001] The invention relates to an active equalization system and an equalization method, in particular to an active equalization system and an equalization method for a power lithium-ion battery pack. Background technique [0002] Power lithium-ion battery packs are generally connected in series. Since the initial capacity, voltage, and internal resistance of each single lithium-ion battery are not exactly the same due to the manufacturing process, it will cause overcharging and over-charging of the single lithium-ion battery during use. When the discharge phenomenon is serious, it will lead to premature aging and failure of individual lithium-ion batteries, and the capacity of the power lithium-ion battery pack will decrease and the working life will be shortened. [0003] During the discharge process, the single lithium-ion battery with low power is discharged first. In order to protect the power lithium-ion battery pack connected in series, the entire pow...

AI Technical Summary

Problems solved by technology

During the charging process, the single lithium-ion battery with the smallest capacity will be fully charged first. In order to protect the power lithium-ion battery pack, the entire power lithium-ion battery pack stops charging, making the other single lithium-ion batteries of the entire power lithium-ion battery pack The battery is not fully charged, and the capacity is seriously reduced

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