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Method for detecting breakage of foil at welding position of lithium battery cell

A detection method and welding technology, which is applied in the field of lithium-ion batteries, can solve problems such as low sensitivity and accuracy, poor voltage or electrochemical performance, and battery fluctuations, and achieve the effect of simple operation and avoiding abnormal battery outflow

Pending Publication Date: 2022-05-13
惠州亿纬集能有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the more common detection method for foil fracture at welding is to judge by testing the internal resistance of lithium-ion batteries, but the internal resistance of lithium-ion batteries is at the milliohm level, and experiments have proved that when laminated batteries appear When the welding foil breaks, the internal resistance of the cell only fluctuates slightly, even if the sensitivity and accuracy of the method for measuring the internal resistance of the battery are low, it is difficult to break the foil at the welding lithium-ion battery Completely singled out, there is a risk of misjudgment and missed judgment
[0004] Once the lithium-ion battery cell with a broken foil at the welding point leaves the factory, the customer may experience poor voltage or electrochemical performance when using the battery cell to assemble the battery module. There are also potential safety hazards during use

Method used

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  • Method for detecting breakage of foil at welding position of lithium battery cell
  • Method for detecting breakage of foil at welding position of lithium battery cell
  • Method for detecting breakage of foil at welding position of lithium battery cell

Examples

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Embodiment 1

[0038] Establish the calibration voltage range: Select 500 1000EA laminated lithium battery cells with a capacity design of 50Ah and a cumulative positive electrode of 50 layers as the calibration cells, charge the calibration batteries with a constant current of 0.05C to 30% state of charge, that is, Charge the calibrated cell with a current of 2.5A to a capacity of 15Ah, collect the voltage data of the calibrated cell, and establish a rectangular coordinate system with the number of calibrated cells as the abscissa and the collected voltage as the ordinate. Draw a voltage distribution diagram in the system, and determine the range of the calibration voltage according to the voltage distribution diagram. Among them, the ordinate value of the scatter point at the lowest position is the lower limit value of the calibration voltage range, and the ordinate value of the scatter point at the highest position is the same as If the difference between the scattered points at the lowest...

Embodiment 2

[0041] In this embodiment, only the cell 2 to be tested with the same specification and model as the calibration cell is preformed and the corresponding voltage data is collected, and the voltage data is compared with the upper limit value of the calibration voltage range obtained in Example 1, Concrete operation steps and parameter are identical with embodiment 1.

Embodiment 3

[0043] In this embodiment, only the cell 3 to be tested with the same specification and model as the calibration cell is preformed and the corresponding voltage data is collected, and the voltage data is compared with the upper limit value of the calibration voltage range obtained in Example 1, Concrete operation steps and parameter are identical with embodiment 1.

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Abstract

The invention relates to a lithium battery cell welding foil fracture detection method comprising the following steps: determining a calibration voltage range, pre-forming a to-be-detected cell, collecting pre-formed voltage data, and comparing the pre-formed voltage data with the calibration voltage range; and if the difference value obtained by subtracting the upper limit value of the calibration voltage range from the numerical value of the voltage data is not smaller than the judgment value, judging that the foil at the welding part of the to-be-detected battery cell is broken. According to the method for detecting the foil breakage at the welding position of the lithium battery cell, no additional working procedure needs to be added, the operation is simple, the cell with the foil breakage at the welding position can be effectively detected, and the abnormal cell is prevented from flowing out.

Description

technical field [0001] The invention relates to the field of lithium-ion batteries, in particular to a detection method for foil fracture at the welding part of lithium-ion batteries. Background technique [0002] Welding is one of the key processes in the preparation of lithium-ion batteries. A common problem in the welding process is that the foil at the welding connection is broken due to sudden fluctuations in welding parameters or defects in individual incoming foils. [0003] At present, the more common detection method for foil fracture at welding is to judge by testing the internal resistance of lithium-ion batteries, but the internal resistance of lithium-ion batteries is at the milliohm level, and experiments have proved that when laminated batteries appear When the welding foil breaks, the internal resistance of the cell only fluctuates slightly, even if the sensitivity and accuracy of the method for measuring the internal resistance of the battery are low, it is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/00
CPCG01N27/00
Inventor 段玉霜许永顺蒋新欣邓昊昆
Owner 惠州亿纬集能有限公司