Method for testing expansion of anode sheet of lithium ion battery

A lithium-ion battery and anode sheet technology, applied in the field of lithium-ion batteries, can solve the problems of inaccurate measurement of the expansion rate of the anode sheet, uneven thickness distribution of the anode sheet, poor data consistency, etc., to achieve easy operation and repeat consistency Good, accurate expansion rate effect

Active Publication Date: 2012-08-15
NINGDE AMPEREX TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This test method can measure the expansion rate of the anode sheet to a certain extent, but there is a certain inhomogeneity in the thickness distribution of the anode sheet. When selecting different test points, using a micrometer to test the thickness of the anode sheet will lead to certain errors. , the consistency of the measured data is poor, and the expansion rate of the anode sheet cannot be accurately measured

Method used

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  • Method for testing expansion of anode sheet of lithium ion battery
  • Method for testing expansion of anode sheet of lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Choose one of the anode sheets to be measured, randomly select an anode sheet, and stick a PP-based tape in the middle of the two adjacent cathode sheets. The tape size is a circle with a diameter of D=3.0cm, and then the processed cathode The cell, the anode sheet and the diaphragm are assembled into the cell by the method of lamination, and then put into the packaging bag, inject an appropriate amount of electrolyte, and let it stand for a certain period of time until the electrolyte fully soaks the pole piece, then charge the cell to 3.0V, and then The prepared battery cell is disassembled in the drying room, and the thickness H of the non-expansion zone of the anode sheet is measured with a micrometer S (Corresponding to the cathode sheet has a lithium-ion insulating material PP-based tape) and the expansion area around the non-expansion zone (corresponding to the cathode sheet without lithium-ion insulating material PP-based tape) thickness H Z , The thickness of the ...

Embodiment 2

[0044] Choose one of the anode plates to be measured, remove the cathode coating with nitromethylpyrrolidone at the middle position of the negative plate corresponding to the penultimate layer of the anode plate, the coating removal area is 3.0×3.0cm square, and then process it. The cathode sheet, anode sheet and diaphragm are assembled into a battery cell by winding method, then put into the packaging bag, inject a proper amount of electrolyte, and let it stand for a certain period of time until the electrolyte fully soaks the pole piece, then charge the battery to 3.8V, After that, the prepared battery cell is disassembled in a drying room, and the thickness H of the non-expansion area of ​​the anode sheet is measured with a height gauge. S (Corresponding to the cathode without coating) and the expansion area around the non-expansion zone (corresponding to the cathode with coating) thickness H Z , The thickness of the anode sheet substrate is known to be H A , Anode expansion o...

Embodiment 3

[0051] Choose one of the anode sheets to be measured, and stick a PET-based tape in the middle of the diaphragm corresponding to the second-to-last layer of the anode sheet. The tape shape is an isosceles trapezoid (a (top side length) = 2cm, b (bottom side length)) = 4cm, h (height) = 3cm), then the cathode sheet, anode sheet, and the processed diaphragm are assembled into a battery cell by winding method, and then put into the packaging bag, inject a proper amount of electrolyte, and stand for a certain period of time for electrolysis After the liquid fully soaks the pole pieces, charge the cells to 4.2V, and then select some cells to discharge to 3.0V, then charge to 4.2V and cycle 10 times. After that, the prepared battery cell is disassembled in a drying room, and the thickness H of the non-expanded area of ​​the anode sheet is measured with a micrometer S (Corresponding to the diaphragm with a lithium-ion insulating material PET-based tape) and the non-expansion zone surro...

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Abstract

The invention belongs to the technical field of a lithium ion battery and particularly relates to a method for testing the expansion of a pole sheet of a lithium ion battery. The testing method comprises the following step of: adhering a layer of a lithium ion insulating material to an anode sheet or a separation membrane before assembling, or removing a certain area of cathode coating by using a solvent so that no lithium ion is embedded into an anode area corresponding to adhering area or the part of a cathode without a coating in a charging process. Therefore, the expansion of the anode sheet can be measured in a charging/discharging process and a circulating process in situ. Compared with the traditional anode expansion testing method, the testing method is used for accurately calculating the anode expansion in the charging/discharging and circulating processes according to the thickness difference of the same anode sheet at different positions, thereby eliminating influences caused by other factors, such as initial thickness difference among the different pole sheets; the obtained result is more accurate and the uniformity is better. The testing method not only can test the expansion rate of a dual-face area of the anode, but also can accurately test the expansion rate of a single-face area of the anode. Furthermore, the testing method provided by the invention is simple and easy to operate, is high in generality and is convenient to actually operate.

Description

Technical field [0001] The invention belongs to the technical field of lithium ion batteries, and particularly relates to a method for testing the expansion of the anode sheet of a lithium ion battery. Background technique [0002] With the progress of the times, people have higher and higher requirements for the appearance of electronic products, and lithium-ion batteries are developing in the direction of lightness and thinness. Therefore, it is necessary to manufacture batteries with high energy density to meet market demand. [0003] Lithium ion batteries generally include a cathode sheet, an anode sheet, a separator spaced between the cathode sheet and the anode sheet, and an electrolyte. The active material in the anode sheet is generally made of materials with mature technology such as graphite. However, active materials such as graphite rebound after cold pressing, causing the volume of the anode sheet to change; during the battery cycle, the intercalation of lithium ions i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01B21/08
Inventor 唐华琼张宁欣游从辉李白清王旅
Owner NINGDE AMPEREX TECH
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