SOH estimation method and device for power battery system of electric vehicle

A technology for power batteries and electric vehicles. It is applied in the direction of measuring devices, measuring electricity, and measuring electrical variables. It can solve the problems of low accuracy and achieve the effect of accurate health status

Pending Publication Date: 2020-06-12
ZHENGZHOU YUTONG BUS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a method and device for estimating the SOH of the power battery system of an electric vehicle to solve the problem of low accuracy of the SOH value of the power battery system calculated in the prior art

Method used

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  • SOH estimation method and device for power battery system of electric vehicle
  • SOH estimation method and device for power battery system of electric vehicle
  • SOH estimation method and device for power battery system of electric vehicle

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Experimental program
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Effect test

Embodiment 1

[0050] In this embodiment, the state of health SOH based on the capacity retention rate of the power battery system CRR , as the state of health SOH of the power battery system, that is, SOH=SOH CRR .

[0051] SOH CRR The calculation formula is:

[0052] SOH CRR =(C Charge +SOC Start charge *C R *SOH BCR ) / C R *100%

[0053] In the formula, SOH CRR Indicates the state of health based on the capacity retention rate of the power battery system this time, SOH BCR Indicates the state of health based on the capacity retention rate of the power battery system calculated last time, where, if the last time is the first time, the corresponding SOH BCR The value defaults to 1; C R Indicates the rated capacity of the power battery system; SOC Start charge Indicates the state of charge of the power battery system at the start of charging, SOC Start charge *C R *SOH BCR Indicates the initial capacity of the power battery system at the beginning of charging (i.e. C Start ch...

Embodiment 2

[0059] combine figure 1 : In this embodiment, at first the method described in Embodiment 1 is used to calculate the state of health SOH based on the capacity retention rate of the power battery system CRR ; Then, calculate the state of health SOH based on the calendar life of the power battery system Cal-life ; Finally, the SOH CRR and SOH Cal-life The weighted summation is performed to obtain the state of health SOH of the power battery system.

[0060] The calculation formula of SOH is:

[0061] SOH=SOH Cal-life *α+SOH CRR *γ

[0062] In the formula, α is SOH Cal-life The weight coefficient of ; γ is SOH CRR weight coefficient of .

[0063] Among them, α+γ=1, and the value ranges of α and γ need to be set according to the cell material system of the battery in the power battery system and the operating conditions of the vehicle. In this embodiment, the value ranges of α and γ are as follows:

[0064] α=[0.1,0.15]

[0065] γ=[0.85,0.9]

[0066] SOH Cal-life The...

Embodiment 3

[0072] combine figure 2: In this embodiment, at first the method described in Embodiment 1 is used to calculate the state of health SOH based on the capacity retention rate of the power battery system CRR ; Then, calculate the state of health SOH based on the equivalent number of cycles of the power battery system Cycle life ; Finally, the SOH CRR and SOH Cycle life The weighted summation is performed to obtain the state of health SOH of the power battery system.

[0073] The calculation formula of SOH is:

[0074] SOH=SOH Cycle life *β+SOH CRR *γ

[0075] In the formula, β is SOH Cycle life The weight coefficient of ; γ is SOH CRR weight coefficient of .

[0076] Among them, β+γ=1, and the value ranges of β and γ need to be set according to the cell material system of the battery in the power battery system and the operating conditions of the vehicle. In this embodiment, the value ranges of β and γ are as follows:

[0077] β=[0.1,0.15]

[0078] γ=[0.85,0.9]

[0...

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Abstract

The invention provides an SOH estimation method and device for a power battery system of an electric vehicle, and belongs to the technical field of vehicle-mounted power battery systems. The SOH estimation method comprises the steps: electrifying a power battery system, and determining the state of charge SOCStart charge of the power battery system at the start moment of current charging; and according to the SOCStart charge, the rated capacity CR of the power battery system, and the health state SOHBCR based on the capacity retention rate of the power battery system, which is calculated lasttime, calculating to obtain the initial capacity CStart charge of the power battery system at the beginning of the current charging: CStart charge = SOCStart charge * CR * SOHBCR; counting the charging capacity CCharge in the current charging process at the charging end moment; according to the CStart charge and the CCharge, obtaining the capacity Cend charge at the charging end moment, wherein the Cend charge = CStart charge + CCharge; and according to the Cend charge and the CR, obtaining the state of health SOHCRR based on the capacity retention rate of the power battery system at this time: SOHCRR = Cend charge / CR * 100%. The accuracy of the health state of the power battery system can be improved.

Description

technical field [0001] The invention relates to an SOH estimation method and device for an electric vehicle power battery system, belonging to the technical field of vehicle power battery systems. Background technique [0002] The state of health (SOH) of the power battery system is a core parameter that reflects the real-time performance index of the power battery system, and the accuracy of its estimation is particularly important. [0003] At present, methods for estimating SOH in the prior art mainly include: based on internal resistance method, cycle number method, etc., but the accuracy of the obtained SOH value is not high. Contents of the invention [0004] The purpose of the present invention is to provide a method and device for estimating SOH of a power battery system of an electric vehicle to solve the problem of low accuracy of the SOH value of the power battery system calculated in the prior art. [0005] In order to achieve the above object, the present inv...

Claims

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Application Information

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IPC IPC(8): G01R31/392
CPCG01R31/3644
Inventor 石赵伟游祥龙邵玉龙
Owner ZHENGZHOU YUTONG BUS CO LTD
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