On-line estimation early warning method for SOH (State Of Health) of electric vehicle battery pack

A technology for battery packs and electric vehicles, applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., can solve problems such as inability to estimate, time-consuming and labor-intensive, and high cost, and achieve low cost, high estimation accuracy, and simple implementation. Effect

Inactive Publication Date: 2015-05-20
GUANGZHOU HKUST FOK YING TUNG RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since this method completely relies on the measurement of battery electrochemical parameters, the obtained electrochemical model cannot be used universally for different types and types of batteries, so it has great limitations and is difficult to put into practical application.
In general, the existing SOH estimation method is mainly based on offline testing, which is time-consuming, laborious, and costly, and it is impossible to estimate the SOH of each battery in the battery pack separately, which is not conducive to timely discovery and replacement of cells with poor SOH. body battery

Method used

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  • On-line estimation early warning method for SOH (State Of Health) of electric vehicle battery pack
  • On-line estimation early warning method for SOH (State Of Health) of electric vehicle battery pack
  • On-line estimation early warning method for SOH (State Of Health) of electric vehicle battery pack

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Embodiment 1

[0056] refer to figure 1 , an electric vehicle battery pack SOH online estimation and early warning method, comprising:

[0057] S1. Every once in a while, conduct an offline charge and discharge test on each single battery, and measure the initial maximum capacity Q of each single battery 0 , and set the SOH value of the single battery at this time to 1, indicating a complete healthy state; as the maximum available capacity of the single battery changes during use, it is determined when it is reduced to the scrap ratio threshold of the initial capacity, that is, k%. In order for the single battery to meet the scrap standard, the SOH value at this time is set to 0. Therefore, when the available battery capacity of the single battery is Q, it is assumed that the SOH value of the single battery is SOH 1 , then there are:

[0058] SOH 1 = Q - k % ...

Embodiment 2

[0077] An electric vehicle battery pack SOH online estimation and early warning method, comprising:

[0078] S1. Every once in a while, conduct an offline charge and discharge test on each single battery, and measure the initial maximum capacity Q of each single battery 0 , and set the SOH value of the single battery at this time to 1, indicating a complete healthy state; as the maximum available capacity of the single battery changes during use, when it drops to 80% of the initial capacity, the single battery is considered to be Reach the scrapping standard, and set the SOH value at this time to 0. Therefore, when the available battery capacity of the single battery is Q, it is assumed that the SOH value of the single battery is SOH 1 , then there are:

[0079] SOH 1 = Q - 80 % * Q 0 ...

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Abstract

The invention discloses an on-line estimation early warning method for an SOH (State Of Health) of an electric vehicle battery pack. The method comprises the following steps: S1, measuring initial maximum capacity of each single battery; S2, acquiring real-time charge and discharge current of each single battery by using a battery management system and estimating an SOC value before and after charge and discharge of each single battery; S3, calculating the SOH value after each charge and discharge of each single battery; S4, judging whether the single battery of which the SOH value is smaller than a first preset threshold value exists in the battery pack, executing a step S6 if the single battery exists, and otherwise, executing a step S5; S5, calculating an average value of the SOH values of all single batteries in the battery pack, judging whether the single battery of which the SOH value differs from the average value for more than a second preset threshold value exists in the battery pack, executing a step S6 if the single battery exists, and otherwise, returning to execute the step S1; S6, triggering the battery management system to enter a protection state and emitting alarm. The method has the advantages of high real-time property, high accuracy, simple implementation mode and low cost and can be widely applied to the monitoring field of the battery pack.

Description

technical field [0001] The invention relates to the field of management and control of battery packs of electric vehicles, in particular to an online SOH estimation and early warning method for battery packs of electric vehicles. Background technique [0002] Battery health status: State Of Health, referred to as SOH, reflects the ability of the battery to show the proper charge and discharge characteristics at a certain point in the charge and discharge cycle. This parameter is related to the aging status of the battery and will affect the battery's performance. performance and longevity. In the electric vehicle battery pack system, as the running mileage of the electric vehicle increases, the battery pack undergoes repeated charge-discharge cycles, the battery will gradually age and degrade, and the internal resistance and available capacity will change. Inconsistencies in the state of health of the battery lead to a decrease in the overall performance of the battery pack...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/36
Inventor 吕洲何波刘博洋姚科高福荣
Owner GUANGZHOU HKUST FOK YING TUNG RES INST
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