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Battery safety diagnosis method based on relaxation voltage curve

A diagnostic method and voltage curve technology, applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., can solve problems such as quantitative diagnosis of battery safety

Active Publication Date: 2021-06-08
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there is currently no method that can quantitatively diagnose the safety of batteries

Method used

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  • Battery safety diagnosis method based on relaxation voltage curve
  • Battery safety diagnosis method based on relaxation voltage curve
  • Battery safety diagnosis method based on relaxation voltage curve

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0049] The specific implementation flow in the embodiment of the present invention is as follows figure 1 As shown, the battery selected for the test in this example is a 18650-type ternary lithium-ion battery. When the battery is fully charged, use a 0.5C constant current charging method to overcharge the battery to a state of charge of 105% and 110% respectively. , 115%, 120%, overcharge the battery to different degrees, and then obtain the relaxation voltage curve when the battery is standing still, such as figure 2 shown.

[0050] Perform differential processing on the obtained relaxation voltage curves of batteries with different degrees of overcharge to obtain the differential voltage curve, thereby obtaining the time corresponding to the first valley of the differential voltage curve, and establishing the state of charge (SOC) and The relationship between the valley time, such as Figure 4 shown.

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Abstract

The invention relates to a battery safety diagnosis method based on a relaxation voltage curve. The method comprises the following steps: 1) overcharging a plurality of batteries to different degrees; 2) obtaining a curve of relaxation voltage changing along with time; 3) acquiring a curve of the corresponding differential voltage changing along with time; 4) acquiring time corresponding to a first valley value of the differential voltage; 5) fitting to obtain the relationship between the overcharged state of charge SOC and the time corresponding to the first valley value; (6) obtaining the corresponding self-heat-production starting temperature; 7) fitting to obtain the relationship between the overcharged state of charge SOC and the self-heat-production starting temperature; 8) obtaining the relation between the time corresponding to the first valley value and the self-heat-production starting temperature of the battery; and 9) for the to-be-detected battery, obtaining the time corresponding to the first valley value of the curve of the differential voltage of the to-be-detected battery along with the time change, and obtaining the self-heat-production initial temperature of the to-be-detected battery. Compared with the prior art, the method has the advantages of simple calculation, accurate prediction and the like.

Description

technical field [0001] The invention relates to the technical field of power battery state diagnosis, in particular to a method for diagnosing battery safety based on a relaxation voltage curve. Background technique [0002] At present, environmental pollution and energy shortage drive the continuous upgrading of the energy industry. Among them, the upgrading of the automobile industry is developing rapidly. Electric vehicles are emerging products in this new energy revolution. Lithium-ion batteries are widely used due to their excellent performance. However, due to the uncertain application environment of electric vehicles and the existence of harsh working conditions from time to time, safety accidents of electric vehicles have occurred frequently in recent years. This is due to the failure of the battery management system and the failure of the charging control during the actual use of the battery, and the thermal stability of the battery will change with the aging of use...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/388G01R31/392
CPCG01R31/388G01R31/392
Inventor 魏学哲张广续戴海峰
Owner TONGJI UNIV