Granulated Cathode Material for Lithium-Ion Battery
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Solution Overview
Problem
Lithium-ion secondary batteries face challenges in maintaining high lithium ion conduction rates and reducing interface resistance when using granulated cathode active materials, as increased welding pressure can cause excessive collapse of granulated bodies, leading to decreased porosity and conduction rates.
Innovation Solution
The cathode material is composed of granulated bodies with an average particle diameter of 0.90 μm to 2.00 μm and 90% of particles within 0.25 μm to 3.50 μm, which suppresses excessive collapse under increased welding pressure, maintaining porosity and enhancing lithium ion conduction rates, and includes a carbonaceous film for improved electron conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If granulated bodies are used to improve electrode coating property, then coating quality is enhanced, but excessive collapse under pressure reduces lithium ion conduction rate
Solution Approach 1:
The patent uses parameter changes by optimizing the particle diameter distribution of granulated bodies to achieve both good coating properties and maintained porosity. The specific size range (average 0.90-2.00 μm) ensures that granulated bodies provide excellent coating quality while resisting excessive collapse during electrode fabrication, thereby preserving lithium ion conduction pathways.
2Ease of manufacture
If flat surface electrode current collector is selected to reduce manufacturing cost, then cost is decreased, but interface resistance increases compared to roughened surfaces
Solution Approach 1:
The patent applies parameter changes in the granulated body characteristics (particle diameter 0.90-2.00 μm average, specific size distribution) to compensate for the lack of surface roughness. This optimization enables the use of cost-effective flat surface current collectors while maintaining low interface resistance, as the controlled granulated body morphology ensures adequate contact area without requiring expensive surface treatments.
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
This configuration results in lithium-ion secondary batteries with excellent input and output characteristics by maintaining high lithium ion conduction rates and reducing interface resistance, ensuring efficient charge and discharge performance.
Implementation Method 1
the lithium ion conduction rate through an electrolytic solution can be improved by appropriately adjusting pores in the granulated bodies
Implementation Method 2
the electron migration resistance between the electrode current collector and the cathode mixture layer is decreased by coating the surface of the electrode current collector with porous carbon
Data Source
AI summary
A cathode material for a lithium-ion secondary battery including: granulated bodies in which primary particles are aggregated, wherein an average particle diameter of the granulated bodies is 0.90 μm or more and 2.00 μm or less, particle diameters of 90% or more of the granulated bodies are 0.25 μm or more and 3.50 μm or less, wherein particle diameters of the granulated bodies are evaluated such that 300 granulated bodies are randomly selected from a view of the granulated bodies using a scanning electron microscope, a plurality of diameters of each of the 300 granulated bodies that pass through a central point thereof are evaluated, and a maximum diameter selected from said plurality of diameters is considered as a particle diameter of each of the granulated bodies.