Method for evaluating single body consistency of power battery pack in dynamic use process

A power battery pack, consistent technology, applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., can solve problems such as power battery pack performance degradation, capacity utilization rate reduction, safety issues, etc.

Inactive Publication Date: 2021-01-29
DONGFENG MOTOR CORP HUBEI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

With the improvement of battery energy density, the safety performance of batteries has become particularly important. Among them, due to the differences of battery cells, some cells will be overcharged or over-discharged, which will lead to damage during the use of the power battery pack. The overall performance drops sharply, which leads to a reduction in capacity utilization and a shortened service life. In severe cases, it will cause safety problems

Method used

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  • Method for evaluating single body consistency of power battery pack in dynamic use process
  • Method for evaluating single body consistency of power battery pack in dynamic use process
  • Method for evaluating single body consistency of power battery pack in dynamic use process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] All monomers are sampled to obtain a capacity increment curve for each monomer.

[0041] 1.1 Selection figure 2 A certain peak x (x is any one of peaks A, B, and C) in the battery pack is used to calculate the dispersion degree KIC of the peak value at the xth peak of all monomer capacity increment curves in the battery pack 总 x , which can be calculated using the following population standard deviation formula:

[0042]

[0043] Among them, IC i x is the peak value of the i-th monomer at the x-th peak, r x is the average value of all battery cells at peak x, and n is the number of cells in the battery pack.

[0044] Calculated KIC 总 x The larger the value is, the worse the consistency of the single unit of the power battery pack is.

[0045]1.2 Calculate the voltage value dispersion KICV corresponding to the xth peak of the capacity increment curve of all battery cells in the battery pack 总 x , which can be calculated using the following population standa...

Embodiment 2

[0054] Only some cells are sampled, and the number of samples is n (that is, the total number of cells in the battery pack is greater than n).

[0055] 2.1 selection figure 2 A certain peak x (x is any one of the peaks A, B, and C) in the battery pack is used to estimate the degree of dispersion of the peak value of the x-th peak of the capacity increment curve of all cells in the battery pack, and the following sample standard deviation formula can be used. estimate:

[0056]

[0057] Among them, KIC 样 x is the estimated value of peak dispersion at the xth peak of all monomer capacity increment curves, IC i x is the peak value of the i-th monomer at the x-th peak, r x is the average value of the peak value of n monomer samples at the xth peak, and n is the sampling number of monomers in the battery pack.

[0058] Calculated KIC 样 x The larger the value is, the worse the consistency of the single unit of the power battery pack is.

[0059] 2.2 Estimate the dispers...

Embodiment 3

[0068] Sampling all monomers to obtain the capacity increment curve of each monomer, record the total number of peaks in the capacity increment curve of each monomer as L, and the corresponding L peak numbers are from the starting point of the x-axis to the right They are the 1' peak, the 2' peak, the 3' peak...the L' peak in turn; respectively select m peaks with the same number of each monomer, and select the m peaks according to the starting point of the x-axis The numbers are given in rear order to the right: the first peak, the second peak, the third peak...the mth peak, wherein, the m satisfies 2≤m≤L.

[0069] 3.1 For the capacity increment curve of each cell, calculate the Jth peak value of all cells in the battery pack through the capacity increment curves of all battery cells in the battery pack (the J is the first peak, the second peak, the 3 peaks...The degree of dispersion KIC of any one of the mth peaks) 总 J , which can be calculated using the following populati...

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Abstract

The invention discloses a method for evaluating single body consistency of a power battery pack in a dynamic use process. The method comprises the following steps of: 1) monitoring voltage, current and temperature data of a target power battery pack in a charging / discharging process; 2) determining a single body capacity increment curve of each single body of the target power battery pack when thetemperature is the same and the charging / discharging is carried out at the same current, and calculating the peak / valley dispersion degree of the single body capacity increment curve; 3) calculatingthe voltage value dispersion corresponding to the corresponding peak / valley value of each single capacity increment curve; and 4) performing weighted average on the dispersion of the corresponding peak value / valley value of each single battery capacity increment curve and the dispersion of the voltage value corresponding to the corresponding peak value / valley value of each single battery capacityincrement curve during charging / discharging, so as to obtain a comprehensive evaluation value of the single consistency of the power battery pack in the use process. By introducing the battery capacity increment curve, the evaluation of the single body consistency is simpler and more precise.

Description

technical field [0001] The invention relates to battery management, in particular to a method for evaluating the consistency of single cells of a power battery pack during dynamic use. Background technique [0002] Due to the advantages of high energy density, long storage life and wide operating temperature range, power batteries are more and more widely used in the field of new energy. With the improvement of battery energy density, the safety performance of batteries has become particularly important. Among them, due to the differences of battery cells, some cells will be overcharged or over-discharged, which will lead to damage during the use of the power battery pack. The overall performance drops sharply, which leads to a reduction in capacity utilization and a shortened service life. In severe cases, it will cause safety problems. [0003] In order to ensure the stable and efficient operation of the power battery pack, it is particularly important to detect problemat...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): G01R31/378G01R31/367G01R31/396G01R31/382G01R31/3842
CPCG01R31/367G01R31/378G01R31/382G01R31/3842G01R31/396
Inventor吴杰余龙曦吴胜杰朱禹周坤
OwnerDONGFENG MOTOR CORP HUBEI