Algorithm for evaluating battery core capacity distribution interval of battery system

Abstract

The invention discloses an online estimation method for evaluating a battery system battery core capacity distribution interval. The method is characterized by obtaining highest / lowest single voltageand current data of a battery core through monitoring; obtaining head and tail open-circuit voltage (OCV) in an operation condition time period by utilizing an identification algorithm, and accordingto the SOC-OCV relationship, converting the open-circuit voltage into the corresponding charge quantity; correcting the charge quantity to a certain extent according to the voltage difference change trend; and making different aging battery cores adopt calculation formulas with different iteration times through a certain condition limitation to solve the problem of overlarge calculation error caused by different OCV changes due to different battery aging, so that the purpose of accurately estimating the available capacity SOH value distribution interval of the battery core online can be achieved only by utilizing the highest / lowest single voltage. Reference can be provided for the repair value and the echelon utilization value of the battery system, online diagnosis can also be performed on the health condition of the battery system, early warning is given out for high-risk vehicles, and vehicle accidents are reduced.

Description

technical field [0001] The invention relates to the technical field of batteries, and more specifically refers to an algorithm for evaluating the capacity distribution interval of battery cells in a battery system. Background technique [0002] After the battery system is loaded and applied, the capacity of the battery cell will gradually decay with the passage of time. However, due to differences in the level of process control in the manufacturing process and differences in the use environment, the cells often show inconsistent capacity decay rates, that is, the available capacity of the cells varies after a period of use. The lowest SOH of the battery cell determines the available capacity of the battery system, the mileage of the vehicle, and the safety of use, while the highest SOH of the battery cell determines the repairability level of the battery system and the available value of cascade utilization. [0003] At present, the existing battery system health assessmen...

AI Technical Summary

Problems solved by technology

[0005] The present invention provides an algorithm for evaluating the distribution interval of battery cell capacity in a battery system, the main purpose of which is to overcome the shortcomings of the existing battery system capacity evaluation such as long test time, low estimation accuracy, and difficulty in fully describing the health status of the battery cells.

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