Positive Electrode Active Material Recycling With 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 and retention of solid carbon, leading to degraded capacity and output characteristics due to its interaction with charge carriers during the baking process.
Innovation Solution
A method involving an alkaline liquid immersion, solid-liquid separation, classification into fine and coarse particle fractions, and a baking step to remove solid carbon physically, thereby suppressing its interaction with charge carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the end material is subjected to alkaline liquid immersion and solid-liquid separation to remove aluminum impurities, then the aluminum content is reduced, but solid carbon adheres to the current collector and remains as impurity in the positive electrode active material
Solution Approach 1:
The patent divides the particle separation process into two distinct stages: first removing aluminum impurities through alkaline liquid immersion and solid-liquid separation, then removing solid carbon impurities through classification into fine and coarse particle fractions. This segmented approach allows each impurity type to be targeted and removed independently, solving the problem of solid carbon adhesion that occurs in single-stage processes.
Solution Approach 2:
The patent extracts solid carbon impurities from the positive electrode active material by classifying particles into fine and coarse fractions, where solid carbon predominantly appears in the fine particle fraction. This extraction process removes the harmful solid carbon while retaining the desired coarse particle fraction containing the active material, thereby improving purity without compromising the main product.
2Productivity
If solid carbon remains in the positive electrode active material, then the material can be collected and reused, but the capacity characteristic and output characteristic are degraded due to response between solid carbon and charge carrier during baking
Solution Approach 1:
The patent performs classification to remove solid carbon impurities before the baking step. By eliminating solid carbon from the fine particle fraction prior to heating, the harmful interaction between solid carbon and charge carrier during baking is prevented in advance. This preliminary removal action ensures that when the coarse particle fraction undergoes baking, the capacity and output characteristics are preserved without degradation.
3Object-generated harmful factors
If classification is performed to remove solid carbon, then the fine particle fraction containing solid carbon is separated, but the process complexity increases with additional classification step
Solution Approach 1:
The patent combines the aluminum removal process (alkaline liquid immersion and solid-liquid separation) with the solid carbon removal process (classification into fine and coarse particle fractions) into a single integrated workflow. By merging these functions sequentially, the patent achieves dual impurity removal without requiring entirely separate processing lines, thus managing process complexity while effectively addressing both aluminum and solid carbon contamination.
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 minimizing the presence of solid carbon, resulting in improved performance.
Implementation Method 1
an aluminum content of the solid substance is equal to or less than 0.03 mass% when a total mass of the solid substance is treated as 100 mass%
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
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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.