Positive Electrode Composite Uniform Conductive Coating
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Solution Overview
Problem
The existing wet process for manufacturing positive electrodes in lithium secondary batteries faces challenges such as solvent removal issues, environmental pollution, and limitations on electrode thickness, while the dry process struggles with uniform dispersion of conductive materials.
Innovation Solution
A positive electrode active material composite is developed with a conductive material uniformly applied on the surface of the active material, using a solvent with a boiling point of 120°C or less, and a specific drying process to achieve a residual solvent content of 0.18 to 1.0 wt%, enabling uniform dispersion without the need for additional solvents during electrode manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wet process is used to manufacture the positive electrode, then the slurry can be uniformly applied on the current collector, but solvent removal causes defects and requires high energy consumption
Solution Approach 1:
The patent extracts and removes the solvent component from the traditional wet process slurry formulation. By using a solvent-free dry mixing process where conductive material is directly mixed with binder and active material particles, the patent eliminates the need for solvent evaporation entirely, thereby removing the energy consumption issue while maintaining uniform distribution through intensive mixing
Solution Approach 2:
The patent changes the fundamental parameter of solvent content from present (wet process) to absent (dry process). This parameter change transforms the process from requiring high-temperature evaporation to a low-energy dry mixing and forming process, achieving both uniform application and low energy consumption
2Quantity of substance
If the electrode thickness is increased beyond a certain value, then the energy storage capacity increases, but the wet process flowability limitations prevent further thickness increase
Solution Approach 1:
By removing the solvent component from the process, the patent eliminates the flowability constraints that limited electrode thickness in wet processes. The dry mixing process allows for the formation of thicker electrodes without relying on slurry flow properties, as the material is formed through direct particle mixing and binding rather than liquid carrier flow
3Object-affected harmful factors
If a dry process is used to manufacture the positive electrode, then solvent-related problems are eliminated, but uniform dispersion of conductive material becomes difficult
Solution Approach 1:
The patent applies preliminary action by pre-mixing the conductive material with the binder in specific proportions before combining with the active material. This preliminary mixing ensures that conductive material is evenly distributed on particle surfaces through intensive mixing, achieving uniform dispersion without requiring solvent as a medium
Solution Approach 2:
The binder serves as an intermediary substance that facilitates uniform distribution of conductive material during dry mixing. The binder coats particles and carries conductive material uniformly, replacing the solvent's dispersing function with a solid-phase binding mechanism that achieves similar uniformity without solvent-related drawbacks
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 composite allows for the production of electrodes with low powder resistance and excellent electrical characteristics, overcoming the limitations of traditional processes by ensuring effective conductive material dispersion and reducing solvent-related issues.
Implementation Method 1
a residual solvent content is 0.18 to 1.0 wt%
Data Source
AI summary
The present invention relates to a new positive electrode active material composite in which a conductive material is uniformly applied on a surface of a positive electrode active material. The positive electrode active material composite according to the present invention has excellent electrical characteristics due to low powder resistance, and is particularly suitable for using in manufacturing a dry electrode due to the conductive material uniformly dispersed on the surface of the positive electrode active material.