Lithium battery charge state estimation method, battery management system and battery system

Abstract

A lithium battery charge state estimation method includes the following steps that an initial electric quantity value of a lithium battery is acquired; based on the initial electric quantity value, the current electric quantity of the lithium battery is preliminarily estimated according to the ampere-hour method; battery circuit model parameters of the lithium battery are corrected according to the recursive least-squares method; based on the preliminarily-corrected battery circuit model parameters, the estimated current electric quantity of the lithium battery is further corrected according to the extended Kalman filtering method. The invention further provides a battery management system and a battery system which adopt the lithium battery charge state estimation method.

Description

technical field [0001] The invention relates to a lithium battery management system, in particular to a method for estimating the state of charge of a lithium battery and a battery management system and a battery system using the same. Background technique [0002] With the increasingly prominent problems of environmental protection and energy saving, due to the advantages of high specific energy and green environmental protection, lithium-ion batteries, as large-capacity power sources, have gradually been applied in the fields of automobiles, aerospace, and ships. The energy density of lithium-ion batteries is getting higher and higher, the capacity is getting bigger and bigger, and the number of battery cells connected in series is also increasing. During the long-term use of the battery pack, due to the consistent Poor performance can easily cause overcharge and overdischarge of one or more batteries, and then the performance of the entire battery module will decline, and...

AI Technical Summary

Problems solved by technology

However, the above correction is only a theoretical situation. In fact, there are many other factors that affect the battery SOC, and the correction function is very verified in actual experiments and applications.

Therefore, so far, it is difficult to obtain a higher accuracy of the SOC value by using the ampere-hour integration algorithm, and there is a large deviation from the actual value.

Some other existing SOC estimation methods include constant current voltage method, open circuit voltage method, internal resistance method, specific gravity method, etc., but these methods have more or less similar defects to the ampere-hour method, and it is impossible to obtain a more accurate SOC estimation, so it is necessary to improve the current estimation method of lithium battery SOC

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