Method, device and system for equalizing lithium battery

Abstract

The invention relates to the field of batteries, and provides a method, device and system for equalizing a lithium battery. The method comprises the steps of in the charging and discharging process ofa lithium battery having a plurality of series-connected electric cores, detecting battery charging and discharging current and terminal voltage of each electric core; estimating open-circuit voltageof each electric core according to an electric core equivalent circuit, the battery charging and discharging current and the terminal voltage of each electric core, and obtaining a first estimated value of each electric core; estimating the residual power of each electric core according to the first estimated value of each electric core, and obtaining a second estimated value of each electric core; starting to perform equalization on the electric cores with the second estimated value meeting a first condition; and stopping equalization on the electric cores with the second estimated value meeting a second condition. Influences imposed on the detected voltage by a polarization phenomenon in the charging and discharging process of the lithium battery is considered, the open-circuit voltageof the electric cores is accurately estimated, the consistence between the electric cores is ensured, and the service life of the lithium battery is prolonged.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a lithium battery equalization method, device and system. Background technique [0002] In recent years, more and more products use lithium batteries as the main power source, mainly because lithium batteries have the advantages of small size, high energy density, no memory effect, high cycle life, and low self-discharge rate. [0003] A lithium battery power supply usually consists of multiple lithium battery cells connected in parallel and in series to meet the voltage and power requirements required by the device. In actual use, although the current passing through a single cell in a lithium battery is the same, even cells of the same model of the same batch have different capacity, internal resistance, and voltage parameters. The capacity is different, the discharge depth of the cell will also be different, the large capacity will be shallowly charged and shallowly discharged, and t...

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Problems solved by technology

[0004] The lithium battery equalization system in the prior art uses the detection of the cell terminal voltage during the charging and discharging process as the condition for whether to start the equalization. There is a large difference in voltage, and there is a large error in the equalization process

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