Detection method for specific capacity of lithium ion battery negative electrode active material after circulation

Abstract

The invention provides a detection method for the specific capacity of a lithium ion battery negative electrode active material after circulation. The detection method comprises the following steps: a lithium ion battery after circulation is discharged and disassembled to take out a negative electrode pole piece; the negative electrode pole piece is drip washed with an organic solvent, soaked in the organic solvent and then aired; the aired negative electrode pole piece is placed in an acid solution and subjected to ultrasonic processing to make a negative electrode diaphragm fall off into the acid solution and be dispersed uniformly, and then a current collector is taken out; the solution where negative electrode diaphragm materials are dispersed uniformly is subjected to solid-liquid separation to obtain solid substance, and the solid substance is drip washed with deionized water repeatedly till the PH value of a formed filtrate is 6-7; the filtrate is subjected to vacuum drying, placed in a protective atmosphere for protection, calcinated at 350-450 DEG C for 3 hours, and ground and sieved after being cooled to obtain negative electrode active material particles; the negative electrode active material particles, a conductive agent, a binding agent and the solvent are mixed uniformly to prepare slurry; the slurry is sprayed on copper foil of a fixed device through a gravity type spray gun containing compressed air in a drying room, and subjected to vacuum drying to obtain the negative electrode pole piece for specific capacity detection after cold pressing, and measurement is conducted after a button cell is assembled.

Description

technical field [0001] The invention relates to a lithium-ion battery detection method, in particular to a lithium-ion battery negative electrode active material specific capacity detection method after cycle. Background technique [0002] With the vigorous development of lithium-ion batteries, the industry's research on lithium-ion battery materials is also getting more and more in-depth. The negative electrode material is an important part of the lithium-ion battery, and its specific capacity affects the capacity and cycle performance of the entire lithium-ion battery. Therefore, it is very important to study the change of the specific capacity of the anode material after multiple cycles of lithium-ion batteries. [0003] The Chinese Patent Application Publication No. CN102610792A published on April 1, 2012 discloses a method for detecting the specific capacity of negative electrode materials of lithium-ion batteries after cycles. The method obtains relatively pure graphi...

AI Technical Summary

Problems solved by technology

However, organic solvent rinsing and acidic solution immersion cannot remove the binder on the surface of graphite powder well, thus affecting the accuracy of specific capacity detection

At present, the negative electrode sheet used to test the specific capacity needs mechanical stirring and scraper coating, which will cause a large loss of materials, thereby increasing the sample amount required for the specific capacity test

However, the testing and analysis of the electrochemical performance of lithium-ion battery anode materials after cycling is not limited to the specific capacity, so the amount of samples that can be used for specific capacity testing is limited.

If magnetic stirring and scraper coating are used, the amount of solvent is increased during the test to meet the demand for less sample volume, which is prone to low viscosity of the slurry and uneven coating of the negative pole piece, so that the specific capacity cannot be measured. test or fail to test accurately

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