Estimation method of battery state of charge and estimation device of battery state of charge

Abstract

The present invention discloses an estimation method of a battery state of charge and an estimation device of a battery state of charge. The estimation method of the battery state of charge comprises: correcting an OCV curve at present and the full charge capacity of the battery at present according to the battery state of charge estimated at the previous time; calculating the battery state of charge at present according to the corrected OCV curve and the corrected full charge capacity of the battery through a corresponding estimation formula; and defining the battery state of charge, the OCV curve and the full charge capacity of the battery as theoretical values when the battery leaves the factory if the current time is the first time. According to the invention, the SOC state parameters at the previous time are taken as confidence parameters of SOC measurement at the current time for calculation, so that the battery service life is longer, the information for memory and study is more sufficient, and obtained OCV curve, full charge capacity of the battery and the like are more appropriate for the battery state and estimated SOC is more accurate.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a method and device for estimating the state of charge of a battery. Background technique [0002] Accurate estimation of battery state of charge (state of charge SOC) is an important basis for secondary battery charge and discharge control and power optimization management, which directly affects the service life and safety of the battery, as well as the performance of the corresponding battery management system and the accuracy of predicting the battery's remaining power usage time sex. It can be seen that the accurate measurement of battery rated capacity and remaining power is a very critical issue. [0003] The SOC of a secondary battery cannot be directly measured by an instrument. It can only be estimated by parameters such as battery terminal voltage, charge and discharge current, and internal resistance. These parameters are also affected by battery aging, ambient temperature c...

AI Technical Summary

Problems solved by technology

[0003] The SOC of a secondary battery cannot be directly measured by an instrument. It can only be estimated by parameters such as battery terminal voltage, charge and discharge current, and internal resistance. These parameters are also affected by battery aging, ambient temperature changes, and battery charge and discharge status. The impact of uncertain factors

Among them, the open circuit method refers to the linear relationship between the open circuit voltage of the battery when it is no-load and its charging state, but the battery must be open circuited, not connected to the load, and it needs to be accurate after a long period of stability. These conditions are used in the daily use of the battery. hard to reach

The Coulomb Ah metering method uses the battery operating current to calculate the integral of the current to time by Coulomb counting, thereby determining the SOC. This method can be used to calculate the SOC in real time, even when the battery is under load. However, the Coulomb Ah metering method Error will increase over time

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