Method for measuring and calculating health status of batteries

Abstract

The invention discloses a method for measuring and calculating the health status of batteries. The method includes the following steps that multiple times of recording is performed on the batteries, the charged capacity variation deltaQm_n and the accumulated charged capacity AHm_n of each stage are measured; two deltaQm_n peak values in record data are found, and the capacity difference deltaAHm between the two capacities corresponding to the two deltaQm_n peak values is calculated; an SOC table is inquired to obtain an SOC corresponding to the two Qm_n peak values; the capacity Qnow_m of each single battery is calculated, and the raw capacity Qnew_m of each single battery is inquired; the SOHm which is equal to Qnow_m / Qnew_m is calculated. According to the method for measuring and calculating the health status of the batteries, a large number of battery parameter tests are not needed, the method is simple and easy to perform, and a battery management system can be used for achieving SOH on-line estimation on each single battery. The SOH of the single battery is fast obtained, maintenance or replacement of the single battery is facilitated, and the service life of a whole battery pack is prolonged.

Description

technical field [0001] The invention relates to a method for measuring and calculating the state of health of a battery. Background technique [0002] The state of health (SOH) of a lithium battery is an important state that reflects battery performance and life. It describes the irreversible reaction of lithium batteries and is a slowly changing quantity. As the number of charging and discharging of the lithium battery pack increases, the battery gradually declines and ages, and the difference in the health status of the battery will gradually be reflected. If the health status of the lithium battery can be tracked and monitored in time, and the single battery whose health status has declined to a critical value is replaced, the service life of the entire lithium battery pack can be greatly extended. [0003] The health status of a lithium battery is related to factors such as internal resistance, battery capacity, battery temperature, charge-discharge rate, and charge-di...

AI Technical Summary

Problems solved by technology

This method needs to test a large number of battery parameters, establish accurate battery models, form empirical formulas, etc. For different batteries, it is difficult to measure battery parameters online. Different battery parameters and models are not the same, so it is not universal

[0004] In addition, the current SOH estimation does not have a method for simultaneously estimating the SOH of each cell in the battery pack, which is not convenient for early detection of cells with poor battery health and replacement

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