Positive Electrode Scrap Recovery Through Heat-Treated Grinding
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Solution Overview
Problem
The challenge of efficiently recycling valuable metals from positive electrode scrap generated during rechargeable lithium battery production, particularly due to the adherence of binders and conductive materials, limits the recovery rate of active materials.
Innovation Solution
A method involving grinding, heat treatment, solvent washing, and separation processes to recover the positive electrode active material, including first and second grinding steps, heat treatment at 400° C. to 600° C., and solvent washing to separate the current collector and active material components effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional recycling methods are used to recover valuable metals from positive electrode scrap, then some metal recovery is achieved, but the recovery rate is limited due to adherence of binders and conductive materials
Solution Approach 1:
The recycling process is divided into multiple sequential steps: first grinding step, heat treatment step, second grinding step, separation step, washing step, and drying step. Each step targets specific aspects of the scrap material to progressively improve recovery rate, transforming a single complex operation into manageable stages that collectively achieve 99% recovery
Solution Approach 2:
The first grinding step is performed before heat treatment to preliminarily break down the scrap structure and expose the active material. This preliminary action facilitates subsequent heat treatment and separation processes, making the overall recycling more efficient and enabling higher recovery rates
2Loss of substance
If heat treatment is applied to remove binders and conductive materials, then separation efficiency improves, but energy consumption increases
Solution Approach 1:
The thermal processing is segmented into controlled heat treatment at specific temperature ranges (400-600°C) followed by cooling and subsequent grinding. This segmentation allows energy-intensive heat treatment to be applied only when necessary for binder removal, followed by mechanical steps that require minimal energy, thus optimizing the balance between purity and energy consumption
Solution Approach 2:
The heat treatment parameters are optimized by controlling temperature within a specific range (400-600°C) and adjusting treatment duration. These parameter changes ensure effective binder and conductive material removal for high purity recovery while minimizing excessive energy consumption that would occur at higher temperatures or longer durations
3Manufacturing precision
If multiple grinding steps are performed to improve particle size distribution, then product quality increases, but processing time increases
Solution Approach 1:
The grinding process is segmented into two distinct steps separated by heat treatment. The first grinding step creates initial size reduction, heat treatment removes binders, and the second grinding step achieves final particle size uniformity. This segmentation allows each grinding operation to be optimized for its specific purpose, achieving high precision without requiring a single excessively long grinding cycle
Solution Approach 2:
The recycling process employs periodic alternation between mechanical grinding and thermal treatment. This periodic action allows the material to undergo cyclic transformations where grinding prepares the structure for heat treatment, and heat treatment prepares the material for more effective grinding, ultimately achieving superior particle size distribution more efficiently than continuous grinding alone
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
Enhances the recovery rate of positive electrode active materials, achieving up to 99% recovery with improved particle size and purity, suitable for reuse in rechargeable lithium batteries.
Implementation Method 1
heat treating the ground positive electrode scrap at a temperature of about 400° C. to about 600° C.
Implementation Method 2
washing the separated active material component with a solvent
Data Source
AI summary
A method of manufacturing a positive electrode active material comprises a first grinding step of grinding a positive electrode scrap of a lithium battery. The ground positive electrode scrap is heat treated. The heat treated positive electrode scrap is ground, and a current collector component and an active material component are separated from the heat treated and ground positive electrode scrap. A solvent is used to wash the separated active material component, solid is separated from liquid, and the solid is dried. With the method, positive electrode active material may be effectively recovered from a positive electrode scrap produced during the fabrication of a rechargeable lithium battery.