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Lithium ion battery tab fracture detection method

A technology of lithium ion battery and detection method, which is applied in the direction of measuring electricity, measuring device, measuring electrical variable, etc., can solve the problems of difficult identification, easy omission of judgment, rupture of tabs of laminated lithium ion battery, etc.

Pending Publication Date: 2021-02-12
WANXIANG 123 CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention aims to solve the problems of difficult identification, judgment and easy omission of tab breaks inside the laminated lithium-ion battery

Method used

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  • Lithium ion battery tab fracture detection method
  • Lithium ion battery tab fracture detection method
  • Lithium ion battery tab fracture detection method

Examples

Experimental program
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Embodiment 1

[0050] A method for detecting the breakage of a tab of a lithium-ion battery, comprising:

[0051] A 45Ah stacked lithium-ion battery of NCM / C system was charged and discharged 50 times. The charge and discharge system was charged to 4.2V with a constant current of 1C, charged to a current of 0.05C with a constant voltage, rested for 10 minutes, and discharged at 1C. to 2.7V. Record the discharge energy and discharge capacity of each cycle, calculate the average voltage of each discharge, and calculate the average voltage of discharge: Among them, ∫u(t)I(t)dt is the discharge energy, and ∫I(t)dt is the battery capacity. Establish the charge and discharge curve model, after calculation, such as figure 1 As shown, the average voltage jumps by 4mV at the 35th cycle. Taking the 35th charge-discharge cycle as an abnormal charge-discharge cycle, compare the data of the 35th charge-discharge cycle with the comparative example, wherein the battery capacity, chemical system and cha...

Embodiment 2

[0055] A method for detecting the breakage of a tab of a lithium-ion battery, comprising:

[0056] A 45Ah laminated lithium-ion battery of the NCM / C system carries out 100 charge and discharge cycles, and the battery charge and discharge system is the same as in Example 1, and the average discharge voltage of each charge and discharge cycle is calculated, and the average discharge voltage of the charge and discharge cycle is calculated Method is the same as embodiment one.

[0057] Such as Figure 4 As shown, the average discharge voltage fluctuated after the 60th cycle, and the average voltage fluctuated the most at the 70th cycle, with an average voltage fluctuation of 47.11% (capacity fluctuation 41.46%), and the voltage change became flat after the 75th cycle, and the 76th cycle The maximum fluctuation of the secondary voltage is 4mV. During the 73rd discharge cycle, the voltage fluctuated downward in a zigzag form between 3.550V and 3.650V, with a maximum fluctuation of...

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Abstract

A method for detecting lithium ion battery tab breakage comprises the following steps: S1, performing charge-discharge cycle on a battery, and recording cycle data; S2, calculating the charging or discharging average voltage of the to-be-tested battery in each charging and discharging cycle, and obtaining an abnormal cycle, according to the charging and discharging curve of the abnormal cycle, ifcharging and discharging cycle data with the data point disengaged from the charging and discharging curve difference value greater than a first preset threshold value exist, determining that tab breakage exists; if the difference value of the separation charging and discharging curve is smaller than a first preset threshold value and larger than a second preset threshold value, detecting the peak-valley slope of the dQ / dV curve; S3, if one of the absolute values of the oxidation or reduction peak slope of the dQ / dV curve of the abnormal cycle is smaller than a preset slope threshold value, judging that the tab is broken. The invention has the beneficial effects that the implicit relation of the voltage capacity curve can be amplified, observation and processing are facilitated, and breakage of the tabs in the laminated lithium ion battery can be identified more easily; and the problems of difficulty in detection and easiness in missing detection of a conventional analysis method are reduced.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a method for detecting the breakage of tabs of lithium-ion batteries, and in particular to a method for detecting the breakage of tabs of laminated lithium-ion batteries. Background technique [0002] Compared with the winding lithium-ion battery under the same system, the laminated lithium-ion battery has the advantages of higher energy density, low internal resistance, good cycle life, good rate performance, and small battery deformation and expansion. It has been widely used in energy and power supply fields. However, due to lamination welding, assembly tab bending, battery pack assembly and other manufacturing processes and internal stress changes under working conditions, single or multiple internal tabs are prone to breakage, resulting in increased internal resistance of the battery and reduced capacity. Attenuation, and even affect the safety performance of ...

Claims

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Application Information

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IPC IPC(8): G01R31/385G01R31/388G01R19/165
CPCG01R31/385G01R31/388G01R19/16542G01R19/16576Y02E60/10
Inventor 张道振韩笑袁园陈彬章鹏王勇
Owner WANXIANG 123 CO LTD
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