Positive Electrode Active Material Purification by Carbon Classification
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Solution Overview
Problem
Existing methods for recycling positive electrode active materials from waste electrode plates result in the adherence of solid carbon to the positive electrode active material, leading to degradation of capacity and output characteristics due to the response of solid carbon and charge carriers during the baking process.
Innovation Solution
A method involving an alkaline liquid immersing step to dissolve the positive electrode current collector, followed by a solid-liquid separation, classification into fine and coarse particle fractions, and a baking step to remove solid carbon, thereby suppressing the response of solid carbon and charge carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the positive electrode active material is collected by crushing, grinding, and mixing with alkaline solution to remove aluminum impurities, then the aluminum impurity is selectively removed, but solid carbon adheres to the crushed current collector and remains as impurity in the positive electrode active material
Solution Approach 1:
The patent extracts solid carbon impurities from the positive electrode active material through a classification process. The mixture is classified into fine particle fraction (containing most solid carbon) and coarse particle fraction (containing most positive electrode active material), thereby separating and removing the harmful solid carbon impurity while preserving the valuable active material.
Solution Approach 2:
The patent changes the particle size parameter by classifying the mixture into different size fractions. By controlling the particle size distribution and separating fine particles (where solid carbon predominantly exists) from coarse particles (where positive electrode active material predominantly exists), the method effectively removes solid carbon impurities while maintaining the integrity of the active material.
2Ease of manufacture
If the solid carbon and positive electrode active material are baked together, then the material is processed, but the solid carbon and charge carrier respond and the capacity characteristic and output characteristic deteriorate
Solution Approach 1:
The patent performs preliminary classification before the baking process. By separating the mixture into fine and coarse particle fractions prior to baking, and selectively removing the fine particle fraction (which contains most solid carbon), the method prevents the harmful response between solid carbon and charge carrier during subsequent baking, thereby preserving capacity and output characteristics.
Solution Approach 2:
The patent converts the potentially harmful presence of solid carbon into a beneficial separation process. By utilizing the particle size difference between solid carbon (fine particles) and positive electrode active material (coarse particles), the classification process effectively removes the harmful solid carbon while preserving the valuable active material, turning a manufacturing challenge into an effective purification opportunity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively suppresses the degradation of capacity and output characteristics of the positive electrode active material by physically removing solid carbon, resulting in improved performance.
Implementation Method 1
an alkaline liquid immersing step for immersing the end material into an alkaline liquid
Implementation Method 2
a solid-liquid separation step for performing a solid-liquid separation on the alkaline liquid after the alkaline liquid immersing step so as to collect a solid substance
Implementation Method 3
a classifying step for classifying the collected solid substance into a fine particle fraction and a coarse particle fraction
Implementation Method 4
a baking step for baking the coarse particle fraction
Data Source
AI summary
The present disclosure has an object to provide a method for manufacturing a positive electrode active material in which performance degradations of a capacity characteristic and an output characteristic are suppressed. The herein disclosed method for manufacturing the positive electrode active material includes a preparation step for preparing an end material of a positive electrode plate containing a positive electrode active material that has never been performing intercalation and deintercalation of a charge carrier, an alkaline liquid immersing step for immersing the end material into an alkaline liquid, a solid-liquid separation step for performing a solid-liquid separation on the alkaline liquid after the alkaline liquid immersing step so as to collect the solid substance, a classifying step for classifying the collected solid substance into a fine particle fraction and a coarse particle fraction, and a baking step for baking the coarse particle fraction.