Method for qualitatively predicting service life of lithium ion battery using EIS test

A lithium-ion battery, life-span technology, applied in the direction of measuring electricity, measuring electrical variables, measuring devices, etc., can solve the problems of complex calculation principles and calculation processes, large errors, etc., and achieve high accuracy, high efficiency, and adaptability strong effect

Pending Publication Date: 2018-12-21
SHENZHEN BAK POWER BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The application number is 201710507702.2, which is a Chinese patent titled "A Method for Testing the Electronic Lifetime of Perovskite Solar Cells Based on EIS Analysis". The electronic life span of perovskite solar cells is calculated through EIS analysis and the establishment of an equivalent circuit model. This method It has the advantages of less damage to the battery, fast calculation speed, and high accuracy. However, as a method for quantitative testing and calculation of battery life, there are objectively complicated calculation principles and calculation processes.
[0006] In the process of evaluating the service life of lithium-ion batteries, we actually pay more attention to the difference between the evaluated positive and negative electrode materials and the control group. Therefore, qualitative evaluation of the cycle life of the battery cell can achieve the desired effect, while qualitative life The accelerated aging method commonly used in prediction has certain limitations in the selection of evaluation parameters. For example, there will be a large error in evaluating the cycle capacity retention rate of accelerated aging in a short time. Therefore, it is necessary to find a method that can be completed in a short time. The method of qualitative prediction of battery life will be the key to achieve a reasonable, accurate and efficient prediction effect

Method used

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  • Method for qualitatively predicting service life of lithium ion battery using EIS test
  • Method for qualitatively predicting service life of lithium ion battery using EIS test
  • Method for qualitatively predicting service life of lithium ion battery using EIS test

Examples

Experimental program
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Embodiment 1

[0032] Select two batches of 18650 cells as the cells to be tested, numbered 1# batch and 2# batch, the difference between 1# batch and 2# batch is the negative electrode material used. Divide the battery cells to be tested for 5 weeks first to ensure that the cells to be tested are fully charged and have no overcharge.

[0033] S01, heat the cells to be tested in a constant temperature box at 40°C for 5 hours, then place the cells to be tested on the test fixture one by one for EIS testing, and do not take out the cells to be tested from the constant temperature box during the test; EIS The tested frequency range is 0.05-10 5 Hz, the EIS test is completed within 2 hours.

[0034] S02, cycle the battery cell after the EIS test in S01 at a temperature of 60°C, the cycle system is a charge-discharge cycle of 0.5C charge and 0.5C discharge, and the cycle number is 0, 10, 30, 50;

[0035] S03, place the cells after the cycle in S02 in a constant temperature box at 40°C for 5 hou...

Embodiment 2

[0043] Select two batches of 18650 cells as the cells to be tested, numbered 3# batch and 4# batch, the difference between 3# batch and 4# batch is the positive electrode material used. Experimental method is with embodiment 1.

[0044] attached Figure 4 It is the change curve of the Rct growth rate of the battery cells to be tested in the 3# batch and the 4# batch in this embodiment with the number of cycles.

[0045] attached Figure 8 In this example, 3# batches and 4# batches of batteries to be tested are charged and discharged at a rate of 0.5C under normal temperature conditions, and the battery capacity retention rate varies with the number of cycles.

[0046] attached by Figure 4 It can be seen that the Rct growth rate of the 4# batch of cells to be tested is faster than that of the 3# batch of cells to be tested, indicating that the cycle performance of the cells to be tested in the 4# batch is poor. attached by Figure 8 It can be seen that under normal temper...

Embodiment 3

[0049] Select two batches of 18650 cells as the cells to be tested, numbered 5# batch and 6# batch, the difference between 5# batch and 6# batch is the negative electrode material used. Experimental method is with embodiment 1.

[0050] attached Figure 5 It is the change curve of the Rct growth rate of the battery cells to be tested in the 5# batch and the 6# batch in this embodiment with the number of cycles.

[0051] attached Figure 9 In this example, the 5# batches and 6# batches of cells to be tested are charged and discharged at a rate of 0.5C under normal temperature conditions, and the capacity retention rate of the cells varies with the number of cycles.

[0052] attached by Figure 5 It can be seen that the Rct growth rate of the 6# batch of cells to be tested is faster than that of the 5# batch of cells to be tested, indicating that the cycle performance of the cells to be tested in the 6# batch is poor. attached by Figure 9 It can be seen that under normal t...

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Abstract

The invention discloses a method for qualitatively predicting the service life of a lithium ion battery using EIS test, comprising the steps of: firstly determining a solution of accelerating the aging of lithium ion battery, which is as follows: performing charging and discharging cycle on a battery cell under a temperature condition of 45 to 60 DEG C using a circulating mode of charging with 0.3to 2C and discharging with 0.3 to 2C; putting the battery cell into a constant temperature box of 35-42 DEG C for constant temperature treatment for 2 to 10 hours after the charging and discharging cycle; performing EIS test on the battery cell and collecting EIS data; fitting the EIS data with a Zview software, and making a changing curve that a Rct growth rate varies with a cycle number; and performing qualitative prediction on the service life of the lithium ion battery according to the changing curve. According to the method for qualitatively predicting the service life of a lithium ion battery using EIS test, the EIS test is a non-destructive test and does not affect the following test result; the prediction time is short; the adaptability is high, and deep research on the electrochemical reaction mechanism of the battery cell is not needed; and meanwhile, the method is high in accuracy, and the accuracy can reach90% or above.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery testing, and in particular relates to a method for qualitatively predicting the service life of lithium-ion batteries by using EIS testing. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high rated voltage, low density, high and low temperature adaptability, and environmental friendliness. With the continuous development of new energy sources, lithium-ion batteries are widely used in household appliances, mobile computers , electric vehicles and other fields. At present, the performance of lithium-ion batteries is constantly improving, and the scope of use is also expanding, which makes the production and consumption of lithium-ion batteries more and more demanding. Reasonable, accurate and efficient methods are used to evaluate the use of lithium-ion batteries Lifespan has become a hot research topic. [0003] A lithium-ion battery is a recharg...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/36
Inventor 赵星许文强张华张国宇任建明
Owner SHENZHEN BAK POWER BATTERY CO LTD
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