An Algorithm for Evaluating the Cell Capacity Distribution Range of a Battery System

Abstract

This patent discloses an online estimation method for the cell capacity distribution interval of a battery system. By monitoring the highest / lowest cell voltage and current data of the obtained cell, the identification algorithm is used to obtain the open circuit voltage (OCV) at the end of the operating condition period, and According to the SOC-OCV relationship, it is converted into the corresponding charge capacity, and the charge capacity is corrected according to the change trend of the pressure difference, and the calculation formula of different iteration times is used for different aging batteries through certain conditions to solve the different problems of battery aging. The problem of excessive calculation error caused by different OCV changes in the future can achieve the purpose of accurately estimating the SOH value distribution interval of the available capacity of the battery cell online only by using the highest / lowest cell voltage; The utilization value provides reference, and can also be used for online diagnosis of the health status of the battery system, to issue early warnings for high-risk vehicles, and to reduce the occurrence of vehicle accidents.

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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