Method for evaluating brittle damage of electrode slice of lithium ion battery

A technology for lithium-ion batteries and pole pieces, applied in strength characteristics, instruments, measuring devices, etc., can solve problems such as the lack of accurate and effective evaluation of brittle damage to lithium-ion battery pole pieces, and achieve the effect of simple and easy methods

Inactive Publication Date: 2009-11-25
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the lack of methods for accurately and effectively evaluating the brittle damage of lithium-ion battery pole pieces in the prior art, and provide a method that can accurately and effectively evaluate the brittle damage of lithium-ion battery pole pieces

Method used

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  • Method for evaluating brittle damage of electrode slice of lithium ion battery
  • Method for evaluating brittle damage of electrode slice of lithium ion battery
  • Method for evaluating brittle damage of electrode slice of lithium ion battery

Examples

Experimental program
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Effect test

Embodiment 1

[0031] This example is used to illustrate the method for evaluating the brittle damage of pole pieces provided by the present invention.

[0032] Preparation of positive electrode sheet

[0033] 1.5 parts by weight of polyvinylidene fluoride was dissolved in 36 parts by weight of N-methylpyrrolidone to prepare a solution, 3.0 parts by weight of acetylene black and 100 parts by weight of LiCoO 2 Add it into the solution, mix well to make a slurry, apply the slurry evenly on both sides of a 16-micron aluminum foil, dry it at 90°C, and roll it with a tablet machine to make a positive electrode sheet with a thickness of 100 microns , and finally rolled and cut into the experimental positive sheet (475 mm × 42 mm.

[0034] Preparation of negative electrode sheet

[0035] Mix by artificial graphite: styrene-butadiene rubber: sodium carboxymethyl cellulose: deionized water=100: 2.5: 1.5: 110 by weight to prepare negative electrode slurry, which is evenly coated on 10 micron copper ...

Embodiment 2

[0039] This example is used to illustrate the method for evaluating the brittle damage of pole pieces provided by the present invention.

[0040] Cells were prepared in the same manner as in Example 1, except that the thickness of the rolled positive electrode sheet was 130 microns.

[0041] According to the same method and conditions as in Example 1, the cell was extruded and unfolded, and it was observed that neither the positive nor the negative electrode sheet cracked the current collector and the electrode material fell off to expose the current collector. Paste a transparent tape (Shanghai Wanyite Technology Co., Ltd.) on the bend of the positive electrode sheet closest to the battery shaft. The width of the tape is 3 cm, the length is 5 cm, and the pressure of the tape is 30 kPa. The time is 10 seconds, and then the pole piece is torn off from the adhesive paper. The situation of the positive electrode material adhered on the gummed paper is as follows: Figure 6 show...

Embodiment 3

[0043] This example is used to illustrate the method for evaluating the brittle damage of pole pieces provided by the present invention.

[0044] According to the same method as in Example 1 to prepare batteries, the difference is that LiFePO 4 instead of LiCoO 2 .

[0045] According to the same method and conditions as in Example 1, the cell was extruded and unfolded, and it was observed that neither the positive nor the negative electrode sheet cracked the current collector and the electrode material fell off to expose the current collector. Paste a transparent tape (Shanghai Wanyite Technology Co., Ltd.) on the bend of the positive electrode sheet closest to the battery shaft. The width of the tape is 3 cm, the length is 5 cm, and the pressure of the tape is 30 kPa. The time is 10 seconds, and then the pole piece is torn off from the adhesive paper. The situation of the positive electrode material adhered on the gummed paper is as follows: Figure 7 shown.

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Abstract

The invention provides a method for evaluating the brittle damage of an electrode slice of a lithium ion battery. The electrode slice comprises a current collector and an electrode material attached to the current collector, wherein the method for evaluating the brittle damage of the electrode slice of the lithium ion battery comprises the following steps: coiling the electrode slice into an electrode coil; squeezing the electrode coil along the radial direction of the electrode coil; and then, expanding the electrode coil, and evaluating the degree of the brittle damage of the electrode slice according to the conditions of cracking of the current collector and/or falling of the electrode material at the bent part of the electrode slice. The method for evaluating the brittle damage of the electrode slice of the lithium ion battery is simple, easy, accurate and reliable, and can guide and optimize the formulation for synthesizing the electrode material, the parameters of the process for coiling the electrode slice and the like according to the degree of the brittle damage of the electrode slice.

Description

technical field [0001] The invention relates to a method for evaluating the brittle damage of lithium-ion battery pole pieces. Background technique [0002] Lithium-ion batteries have the advantages of small size, high working voltage, high specific energy, long cycle life, no memory effect and no pollution, and have been more and more widely used in various portable electronic products. [0003] The positive and negative plates composed of positive and negative active materials are the core components of lithium-ion battery cells, and their performance directly affects the capacity, cycle performance and safety performance of secondary batteries. [0004] During the battery manufacturing process, especially during the winding and extrusion process, there will be irrecoverable creases, material dropping, and even fractures at the bending of the pole piece. This phenomenon is called brittle damage of the pole piece. At present, the common lithium-ion battery manufacturing pr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N3/00
Inventor 刘峰刁家喜
Owner BYD CO LTD
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