Battery state evaluation system and method based on reconfigurable circuit

Abstract

The invention provides a battery state evaluation system and method based on a reconfigurable circuit, and belongs to the technical field of power electronics. Comprising the steps of establishing a single battery reconstruction circuit of a battery pack; the single battery Bi is isolated in the single battery reconstruction circuit, and a Bi measurement loop composed of the single battery Bi, the MOS switches Qi, i and the MOS switch Q3 is formed; inputting a constant current I to the Bi measurement loop, and enabling the single battery Bi to be in a charging state; in the charging process of the single battery Bi, the Bi measurement loop is subjected to circuit breaking operation once every T time and stands for 1 s, and the terminal voltage Uout of the single battery Bi is collected and recorded as a changing curve of the Uout along with the time t; based on the battery monomer equivalent circuit of the battery monomer Bi, analyzing an expression of the battery open-circuit voltage Uocv of the battery monomer Bi according to the change curve of the Uout along with the time t; and through an EKF algorithm, obtaining an expression of a single battery state St of the single battery Bi according to the battery open-circuit voltage Uocv.

Description

technical field [0001] The present invention relates to the technical field of power electronics, and in particular, to a battery state evaluation system and method based on a reconfigurable circuit. Background technique [0002] In recent years, many studies have been carried out on the SOC estimation method for battery cells in the application of electric vehicles and grid-side energy storage systems. The battery SOC estimation method in the on-board electric vehicle energy storage system generally adopts the method of “full discharge” of the battery to verify the battery capacity. application scenarios, and the charge capacity of the battery depends on many factors, including average current, charge cut-off voltage, electrolyte temperature, and aging. The battery cells are suitable for parallel or series connection in the electric vehicle energy storage system. In the battery module connected in series, if the SOC of a battery cell reaches 100%, the module will stop char...

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Problems solved by technology

In addition, for the estimation of single SOC during the operation of electric vehicles, the OCV-SOC mapping curve is an important means to correct the ampere-hour integral method, but considering that within a large SOC range (30% to 70%), the OCV-SOC The corresponding relationship is relatively flat, and the precise correspondence of the battery SOC cannot be achieved, and the robustness and accuracy of the battery cell SOC estimation process are low

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