Positive Electrode Slurry Dispersion for Low-Resistance Battery Storage
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Solution Overview
Problem
Existing secondary batteries face challenges in reducing internal resistance and inhibiting gas release during high-temperature storage, necessitating improved conductive material dispersion liquids and slurries for positive electrodes.
Innovation Solution
A conductive material dispersion liquid with a specific Hansen solubility parameter distance (Rd) of 10.0 MPa1/2 or less is used, comprising a carbon material and dispersant, along with a slurry containing a binder, to form a positive electrode with reduced internal resistance and enhanced high-temperature storage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbon materials are used as conductive materials in electrode slurries, then electrical conductivity is improved, but carbon materials have a high tendency to aggregate which reduces dispersion uniformity
Solution Approach 1:
A dispersant is introduced as an intermediary substance between the carbon material and the dispersion medium. The dispersant adsorbs onto the carbon material surface, providing steric or electrostatic repulsion that prevents aggregation while maintaining electrical conductivity. This mediator enables both good dispersion uniformity and electrical conductivity to coexist.
Solution Approach 2:
The invention changes the chemical and physical parameters of the dispersion system by selecting a dispersant with specific Hansen solubility parameters that match the carbon material. By adjusting the HSP distance between dispersant and carbon material to be 10.0 MPa1/2 or less, the system achieves optimal dispersion while maintaining conductivity.
2Reliability
If internal resistance of secondary battery is reduced by improving conductive material dispersion, then electrical performance is improved, but gas release during high-temperature storage increases
Solution Approach 1:
The invention precisely controls the Hansen solubility parameter distance between dispersant and carbon material to be 10.0 MPa1/2 or less. This parameter optimization achieves sufficient dispersion to reduce internal resistance while avoiding excessive dispersant-carbon interaction that would cause electrolyte decomposition and gas release during high-temperature storage.
Solution Approach 2:
The invention uses the Hansen solubility parameter system as a predictive model to copy successful dispersion conditions from one carbon material system to another. By matching HSP parameters, the same dispersant can achieve optimal performance across different carbon materials without causing harmful side effects.
3Stability of the object's composition
If dispersant amount is increased to improve carbon material dispersion, then dispersion uniformity is improved, but viscosity of the slurry increases which affects processing
Solution Approach 1:
By optimizing the HSP distance parameter between dispersant and carbon material to be 10.0 MPa1/2 or less, the invention achieves effective dispersion with minimal dispersant dosage. This parameter optimization reduces the amount of dispersant needed, thereby controlling slurry viscosity and maintaining good processability.
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 solution effectively reduces internal resistance and improves high-temperature storage characteristics of secondary batteries by ensuring uniform dispersion and adherence of carbon materials, inhibiting gas release, and maintaining viscosity stability.
Implementation Method 1
a technique of premixing a carbon material and a dispersant in a dispersion medium to prepare a conductive material dispersion liquid and then combining the obtained conductive material dispersion liquid with an electrode active material, etc., to produce a slurry for an electrode has been proposed with the aim of sufficiently dispersing the carbon material
Implementation Method 2
an HSP distance (Rd) of Hansen solubility parameters (HSPc) of the carbon material and Hansen solubility parameters (HSPd) of the dispersant is 10.0 MPa1/2 or less
Data Source
AI summary
Provided is a conductive material dispersion liquid that can reduce internal resistance of a secondary battery while also ensuring good high-temperature storage characteristics of the secondary battery. The conductive material dispersion liquid contains a carbon material, a dispersant, and a dispersion medium. An HSP distance (Rd) of Hansen solubility parameters (HSPc) of the carbon material and Hansen solubility parameters (HSPd) of the dispersant is 10.0 MPa1/2 or less.