A test method for mixing uniformity of lithium battery negative electrode materials

Abstract

The invention relates to a method for testing the mixing uniformity of negative electrode materials of lithium batteries. The method comprises mixing conductive carbon and graphite to obtain a mixture, and testing and calculating the measured mass ratio of conductive carbon at any n positions in the mixture. , if the difference between the measured mass ratio of conductive carbon at any n positions and the theoretical mass ratio of conductive carbon in the added raw material is within ±0.1%, it means that the negative electrode material is mixed evenly; The method provides a guiding direction for the improvement of the mixing process, and is conducive to improving the efficiency of the negative electrode material preparation process.

Description

Technical field [0001] The present invention relates to the field of preparation of lithium batteries, and more particularly to a test method of mixing uniformity of a lithium battery anode material. Background technique [0002] In the existing lithium battery production process, the negative electrode material graphite is mixed with the conductive carbon, but the graphite and the conductive carbon are mixed uniform, and there is no accurate method of quantitative characterization. [0003] CN102661911A discloses a method of rapidly detecting powder material mixing uniformity, first understand the performance of the mixed material, then mix after sampling, then calculate, calculate the deviation value, then evaluate according to the size of the deviation, when deviation When the value is not more than 10%, it is considered that the material has been mixed uniform. If it is more than 10%, it will continue to mix, then re-sampling detection until the required deviation value; this...

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Problems solved by technology

[0003] CN102661911A discloses a method for quickly detecting the mixing uniformity of powder materials. First, understand the various properties of the mixed materials, then take samples after mixing, and then calculate the deviation value through calculation, and then evaluate according to the size of the deviation value. When the deviation When the value is not greater than 10%, it is considered that the material has been mixed evenly. If it is greater than 10%, it is necessary to continue mixing again, and then re-sampling and testing until the required deviation is reached; this scheme has the problems of complicated testing process and insufficient accuracy.

[0004] CN106404584A discloses a method for evaluating the uniformity of dry-mixing of lithium-ion battery powder, specifically adding dry powder materials and magnetic iron powder in the lithium-ion battery slurry to the mixer in turn for stirring; randomly taking out n parts of powder samples, each Each powder sample is weighed separately, and the magnetic iron powder in each powder sample is absorbed by a Gaussian magnetic rod, and then the remaining sample is weighed, and then the coefficient of variation of the mixing uniformity of the material is calculated according to the formula; If the obtained coefficient of variation CV is less than 10%, the dry mixing uniformity of the lithium-ion battery slurry powder is good; and the smaller the coefficient of variation, the more uniform the dry-mixing of the lithium-ion battery slurry powder. Defects in testing the homogeneity of mixtures containing magnetic materials in samples

[0005] Although the above-mentioned documents disclose some test methods for testing the mixing uniformity of materials, there are still problems that the test process is complicated and only applicable to the test of mixtures containing magnetic materials. Therefore, it is simple to develop a test method with high accuracy. And the test method suitable for the mixing uniformity test of lithium battery anode materials is still of great significance

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